Dictionary of Ichthyology

Brian W. Coad and Don E. McAllister^†

Revised: 16 November 2008

R

r = availability (the part of a fish population which lives in areas where it is susceptible to fishing during a given fishing season. This part receives recruits from or becomes mingled with the non-available part of the stock at other seasons, or in other years (Ricker, 1975). Fish become available through migration, movement in the water column, or growth).

r = r.

r-selection = a life history strategy characterised by early maturity, rapid growth, large numbers of young produced at an early age, small body size, high mortality and short life span. This strategy is an adaptation to an unpredictable environment such as that found in the Arctic.

raag = rag.

race = 1) a geographical group of populations or a population differing from others. Formerly used as a synonym of subspecies. Now used to refer to units below the subspecies level which are not given taxonomic names. An infrasubspecific category which has no status under the International Code of Zoological Nomenclature.

race = 2) a very rapid current through a narrow channel.

race = 3) the course or track of a boat engaged in ripper-fishing (q.v.)(Scottish dialect).

race-to-fish = a pattern of fishing characterized by an increasing number of highly efficient vessels fishing at an increasing pace, with season length becoming shorter and shorter; a management system where individual boats race to take as much of the total allowable catch before the fishery closes. Also called olympic fishing and derby style fishing.

raceway = concrete, elongate and rectangular fish-rearing unit generally associated with a hatchery which has a large volume of flowing water, able to sustain greater fish densities than ponds, and able to maintain a cleaner environment. Used particularly for trouts, and less often catfishes. May be 100 m long, 1-10 m wide and 0.5-1.5 m deep and made of concrete (usually), brick, tile, earth or lined with plastic.

rack = 1) wooden structures on which cod were hung to dry in winter.

rack = 2) the unit on which tuna fishermen stand, a removable outboard platform (fishing rack).

rack = 3) the remains after pressing herring for oil; used as a fertiliser. Also called pumie

rack = 4) a wooden structure placed in a river to block migrating salmon, directing them into a pound (Newfoundland).

rack = 5) a ford or a ridge of gravel in a river or tidal area.

rack rider = a young salmon or parr, from rack (4).

rackling = long, narrow (2.5 cm) strands cut from halibut sides with a fat content of about 2%. The strands are left joined at the "collarbone", brined and air-dried. Other fish with a 2% fat content may be used.

rade = raith.

radial = 1) a bony or cartilaginous support for a fin ray or spine. Usually three - the proximal, middle and distal radials. If the proximal radial is notably larger it is spoken of as a basal. Teleosts have only one row of radials between the fin rays and the supporting skeleton and these are called actinosts. More primitive fishes have more, e.g. Polyodon has 13, Acipenser has 9.

radial = 2) direction away from the axis running antero-posteriorly through the middle of the organism or structure; peripheral.

radial formula = counts of fin rays (see ray below and individual fins for counting methods).

radial intercalation = ordered cellular repacking among deep cells of the deep and shallow regions of the blastodisc, beginning during the late blastula period and perhaps continuing during gastrulation. This effects epiboly and produces a uniformly thin blastoderm.

radiation = rapid cladogenesis. Called adaptive radiation when a new feature enables a lineage to occupy a new niche or habitat.

radices caudæ = plural of radix caudæ.

radii = plural of radius.

radiograph = an x-ray plate, used to see internal characters such as vertebral counts.

radius (plural radii) = 1) ray.

radius (plural radii) = 2) grooves radiating from the centre of a scale towards the margin. Sometimes transverse in Clupeidae. Primary radii extend from the focus to the margin, secondary radii being outside of the focus. Also called sulci.

radix caudæ (plural radices caudæ) = caudal peduncle (the wrist-like portion of the posterior part of the body between the end of the anal fin and the base of the caudal fin. Its length is measured between the insertion of the anal fin and the caudal flexure (the fold shown by the hind edge of the hypural plates when the caudal fin is flexed). Depth is measured vertically at the narrowest point. Called tail wrist in angling).

raed = raith.

raft = a floating cage, box or platform.

raft fishing = 1) rafts floating on the water surface where fish become stranded. The fish may try to jump over them on moon-lit nights or fish may be scared towards the raft by noise from boats. A series of connected rafts may be used to encircle a school of fish which is then driven towards the rafts. Some rafts have nets hanging down from their edge to discourage fish from swimming under them.

raft fishing = 2) rafts constructed in open water to attract schools of such fishes as tuna so as to make them easier to catch by their concentration.

raft trap = a raft is overlain with twigs and such fish as mullet, jumping on the raft on their own volition, become trapped among the twigs.

rag = 1) to catch a fish by striking with the hook (Scottish dialect).

rag = 2) a lean or scraggy animal or fish (Scottish dialect).

raggedy = said of cod in Newfoundland that were imperfectly dried and had a rough, slightly cracked surface.

raggie = diseased fish infected with fungus (Scottish dialect).

raick = raik.

raid = raith.

raik = a stretch of river used for salmon fishing (Scottish dialect). Also spelled raike, rake, raick, rek, reck, reack and ryke.

raik dyke = a stone dam built across a dyke (Scottish dialect).

raike = raik.

rail = fishing with a hand-line over the rail of a boat.

rain shadow = a dry region on the lee side of a mountain range where rainfall is less and fish faunas may be depauperate.

rains of fishes = fishes falling from the sky like rain or in rain, the result of waterspouts and whirlwinds (see account by Gudger (1921)).

raip = rape.

raise net = a type of fixed net which rises and falls with the tide.

raise the herring = to induce herring shoals to rise to the level of the nets by magical ceremonies.

raised-pillar reel = a fishing reel with extensions on its side-plates, to which the frame pillars are attached, allowing more line to be wound on the spool.

raising = 1) estimating the total from a sample, by multiplying all the fractions in the sample by a raising factor equal to the proportion of the total which the sample represents, e.g. for a fishery by raising catch-at-size samples to the magnitude of the total catches, i.e. by multiplying the sampled numbers times the ratio of sample weight to total catch weight (or the ratio of sample numbers to total numbers).

raising = 2) growing fish by some artificial means of encouragement or assistance.

raith = a deep-sea fishing ground allocated to a particular fisherman or boat (Scottish dialect). See also raid, rade, raed and red.

rake = 1) a set of hooks attached to a structure such as an iron bar up to 8 metres wide towed behind a boat and impaling any fish encountered.

rake = 2) an implement like a large garden rake used to stir up the bottom of a lake or river. This attracts fish; used in the nineteenth century in England and effective for gudgeon (Gobio gobio).

rake = 3) raik.

rake trawl = a beam trawl with a rake or toothed structure along its lower edge to disturb and facilitate capture of flatfishes.

rakorret = freshwater trout, gutted, lightly salted and fermented (Norway).

ram ventilation = the extraction of oxygen during the passage of water over the gills owing to motion through the water rather than active, muscular pumping. Used by Echeneis naucrates when hitching a ride.

ram's horn = 1) a box with slatted sides and holes in the bottom, used for washing fish in Newfoundland. The box was lowered into the water supported by straps attached to a boat or the wharf and men would sit on the edge to scrub the fish with brushes.

ram's horn = 2) a winding-net supported by stakes, used to capture fish coming in on the tide (Newfoundland).

ramification = side branch, e.g. in barbels of Synodontidae.

ramifying = branching, dividing.

rampani net = a very long shore seine operated by 60-80 fishermen in India.

ramus = a branch; one side of the lower jaw.

ramus impar = an unpaired nerve-like structure found in Myxines formed from the two intestinal rami of the vagus nerve united dorsal to the intestine. It contains numerous ganglion cells and cholinergic and adrenergic neurons.

ranching = commercial raising of fishes. Usually juvenile fish are released to a natural habitat for growth to a harvestable size, but see tuna ranch.

ranching to the rod = raising and releasing salmon smolts which migrate to sea and return to be caught by anglers. Wild stock do not then have to compete with hatchery fish in the freshwater environment.

rancidity = fish having a rancid flavour or odour acquired during storage from oxidation or hydrolysis of fat.

range = the geographical area inhabited by a species or other group. The range may be continuous or discontinuous (with gaps).

range extension = the record of a species outside its usual range.

range of tide = the difference in height between consecutive high and low waters.

ranivore = a feeder on frogs.

ranivorous = feeding on frogs.

rank = 1) the position of a taxon in a hierarchy of classification.

rank = 2) a fishing ground (Scottish dialect).

ranksman = a member of a boat crew that has decided to fish in company with another boat and divide catches equally (Scottish dialect).

rapacious = grasping, predatory.

rapala knot = a knot used in angling to tie a lure to the line. An open loop at the lure allows free action. Various websites have animated steps showing how to tie this knot.

rape = to fix a fishing net to the head rope (Scottish dialect). Also spelled raip.

Raphael = the archangel, usually depicted in Christian art by a pilgrim’s staff, or carrying a fish, in allusion to his aiding Tobias (see Tobit) to capture the fish which performed the miraculous cure of his father’s eyesight.

raphe = in anatomy, a seam-like line or ridge between two similar parts of a body organ.

rapidograph = a trade name, often used generically for a technical pen. Such pens, with India ink (q.v.), are used to write permanent labels for immersion in jars with fish specimens.

rapids = a stretch of water in a stream or river with small waterfalls and turbulent, rapid water over coarse substrate. The gradient is about 4-8%.

rare (or vulnerable) = any indigenous species of fauna or flora that is particularly at risk because of low or declining numbers, occurrence at the fringe of its range or in restricted areas, or for some other reason, but is not a threatened species; such vulnerable species require careful watching.

Rassenkreis = a species composed of several geographical subspecies, a polytypic species (German), e.g. in Istiblennius periophthalmus (Salariidae).

rastrate = rake-like.

rat = slang for a very small fish.

rat-l-trap = original name and type of lipless crankbait, q.v. Used as a general term for crankbaits.

rat-tailed maggot = often the mousie (q.v.) used in ice fishing, the rat-tailed maggot of the hoverfly, cultured as bait. The rat-tail is a telescopic siphon used as a snorkel for breathing while submerged.

ratchet effect = the constant increase in exploitation due to the fact that positive short-term economic benefits often cannot be counterbalanced by the uncertain predictions of possible deleterious effects.

rate of exploitation = the fraction, by number, of the fish in a population at a given time, which is caught and killed by man during the year immediately following (= FA/Z when fishing and mortality are concurrent). The term may also be applied to separate parts of the stock distinguished by size, sex, etc. Abbreviated as u or u (Ricker, 1975). Also called fishing coefficient.

rate of fishing = instantaneous rate of fishing mortality (the decrease in numbers of fish over time when fishing and natural mortality act concurrently (Nt = No * e^-Zt , where No is the initial number and Nt is the number of the remaining fish at the end of time t. Z is the instantaneous total mortality rate, usually composed of M + F, where M is the natural mortality rate and F is the mortality rate caused by the fishery)). Abbreviated as F.

rate of growth = growth rate (1) the increase in weight of a fish per year (or season), divided by the initial weight; often measured in terms of K in the von Bertalanffy curve for the mean weight as a function of age (W = Wmax (1-exp (-K age)). Fish grow continuously, although more slowly as they become older. In a managed fishery, fish are allowed to grow to an age which produces good yields, neither too young (still growing rapidly) nor too old (growing slowly)).

rate of natural increase = instantaneous rate of surplus production (equal to rate of growth plus rate of recruitment less rate of natural mortality - all in terms of weight and on an instantaneous basis. In a balanced or equilibrium fishery, this increment replaces what is removed by fishing, and rate of surplus production is numerically equal to rate of fishing (Ricker, 1975)).

rate of removal = a poorly defined term that can mean either rate of exploitation or rate of fishing depending on the context (Ricker, 1975).

rate of utilisation = similar to rate of exploitation, except that only the fish landed are considered. The distinction between catch and landings is important when considerable quantities of fish are discarded at sea (Ricker, 1975).

Rathke's pouch = an embryonic invagination of the stomodeal ectoderm (roof of the embryonic mouth) which migrates dorsally to come into contact with diencephalon. It differentiates into the anterior pituitary gland or adenohypohysis. It becomes a blind naso-hypophyseal canal in some Agnatha or develops secondary opening to the outside with or without a connection to the mouth. Also called craniobuccal pouch.

ration = the amount of feed allowed in an aquaculture facility for a given fish over a day.

rational fishery = a fishery designed to catch the maximum amount of quality fish in the most efficient manner.

rattle = 1) glass or metal objects added to lures which make a noise and attract such fish as bass (Micropterus spp.).

rattle = 2) a shallow, rocky declivity in a stream, rapids or a waterfall (Newfoundland).

rattle = 3) a narrow passage, inlet or arm of the sea, swept by strong tides (Newfoundland).

rattler brook = rattle (2).

rattling = the noise made by a fast-flowing stream (Newfoundland).

raun = rawn.

ravine = a watercourse larger than a gully but smaller than a valley. Not as incised as an arroyo or gulch.

ravine pond = a pond constructed by damming a ravine, and having spillways.

raw saith = bait, such as chopped up limpets, thrown into the water to attract fish (Scottish dialect).

rawn = the roe of fish (Scottish dialect). See also raun, rowan and rouny.

rawner = a mature but not spawning salmon.

ray = 1) a ray (excluding spines) is a flexible, rod-like segmented and often branched, bilaterally paired fin support of dermal origin. Rays may be divided into soft-rays (as just described) and hard-rays or pseudacanths which are ossified, inflexible and superficially like a spine (pseudacanths are found in some Cyprinidae, all Ictaluridae, Notacanthidae, etc.). Called dermatrichs as their origin is dermal. Ray counts are given in Arabic numerals, e.g. 11-14. Simple (rudimentary) fin rays are small, unbranched, unsegmented soft rays usually found at the beginning of a fin. The term ray is sometimes used generically to include spines, which are unpaired and unsegmented, usually sharp and stiff rods supporting the membranes of the fins. Spine counts are given in Roman numerals, e.g. X-XII.

ray = 2) a common name for some members of the skate family Rajiidae in the Order Rajiformes, from the Latin raia for this type of fish.

ray length = the distance from the extreme tip to the base of that ray.

ray net = a large mesh tangle net for catching rays and shallow water anglerfishes.

rayless dorsal fin = adipose fin (a small fleshy fin lacking rays or spines but reinforced by actinotrichs posterior to the soft dorsal fins (rarely a hard ray or a few soft rays may be developed in the adipose fin of certain catfishes), e.g. in Salmonidae, Osmeridae, Argentinidae, Myctophidae, Ictaluridae, Percopsidae).

raw data = un-analysed information.

re- (prefix) = again, repeat.

re-introduction = the stocking of a species into waters where it had become extirpated.

re-spool = replacing old line on a reel with new line.

reach = 1) a section of a stream or river between two defined points, a continuous extent of water. More specifically a length of channel uniform with respect to discharge, depth, area and slope.

reach = 2) an area of a river, e.g. the upper reaches are where the river begins, the lower reaches the final stages.

reach = 3) an arm of the ocean extending into the land.

reach = 4) a straight section of restricted waterway of considerable extent, much longer than a narrows.

reach cast = a cast when fly fishing used for adding extra slack to the line, or when fishing downstream, to ensure a natural presentation.

reack = raik.

read = to interpret scale or other rings in terms of age and growth.

ready-to-eat fish = any fish, other than canned fish, that does not require preparation except thawing or reheating before consumption.

real catch = the weight of fish taken from a water body, gross catch.

reaper = in angling, a soft plastic lure resembling a leech.

rear = 1) to feed and care for in a natural or artificial environment.

rear = 2) to breed.

rear admiral = the master of the third English fishing vessel to reach a harbour in Newfoundland. This position gave the owner certain privileges for the season under the admiral and vice-admiral.

rearing = the amount of time that juvenile fish spend feeding in nursery areas of rivers, lakes, streams and estuaries before migration, or the care and support for young fish.

rearing habitat = areas where larval and juvenile fish find food and shelter.

rearing pond = 1) an artificial impoundment in which juvenile fish are raised prior to release into the natural habitat.

rearing pond = 2) all types of ponds in which fish are grown.

rearing station = an establishment for hatching and rearing stocked fishes.

reast = reest.

reballing = clatting (fishing for eels with a cluster or clot of worms, each of which has had a strong worsted drawn through the length of its body (English dialect). See also quod and clotting).

rebuilding = action allowing a stock or population to grow back to a pre-defined target level.

rebuilding analysis =use of biological data to describe the probability that a stock will rebuild within a given time under a management plan.

recall bias = faulty memory as it affects reporting of catches in angler surveys.

receiving waters = water bodies that receive treated or untreated waste waters.

Recent = a geological epoch within the Quaternary Period ca. 10,000 years BP to the present day. Also called Holocene.

recent = 1) extant, still in existence.

recent = 2) abbreviation for recentiorum.

recent colonist = a species that has extended its range recently by natural means and is reproducing.

recentiorum = of recent authors.

recessus lateralis = intercranial space into which open the major cephalic lateral line canals. It is separated by a membranous fenestra from the spaces of the ear in Clupeidae.

reck = raik.

Recommendation = an advisory statement in an Article of the International Code of Zoological Nomenclature; these are not mandatory.

reconditioned fish = mended fish (post-spawning fish that have or are recovering).

recovered fish flesh = recovered flesh.

recovered flesh = the flesh of a fish separated from skin and bones by mechanical means (see bone separator). Also called minced fish, mechanically recovered fish flesh, recovered fish flesh, boneless fish meat and deboned fish flesh.

recovery rope = lazy deckie (a rope to haul the cod end to a ship's side).

recreational fisher = one participating in a recreational fishery.

recreational fishery = fishing for personal use, entertainment, sport and challenge; does not include sale of catch but does include the businesses associated with it. Also called recreational harvest.

recreational harvest = recreational fishery.

recruit = an individual fish that has moved into a certain class, such as the spawning class or fishing-size class through growth, migration, etc.

recruit stock = the stock that each year is added to the portion of the fishable population.

recruit-to-spawner ratio = an estimate of the number of recruits (fish that are available for harvest in addition to those that escape the fishery to spawn) produced by the previous generation of spawners. The spawner-to-spawner ratio estimates the number of spawners (those fish that reproduced or were expected to reproduce) in one generation produced by the previous generation of spawners. A spawner-to-spawner ratio of 1.0 indicates that, on average, each spawner produced one offspring that survived to spawn; the size of such a population would remain unchanged over that generation.

recruitment = 1) the new members by immigration and/or numbers of fishes born in a given year, or entering a certain class, such as the spawning class or a fishing-size class. Recruitment to a fishery varies greatly from year to year, depending on all sorts of environmental variables, with a few large year classes among many small year classes.

recruitment = 2) recolonisation of a place by a species or fauna.

recruitment curve = a graph of the progeny of a spawning at the time they reach a specified age, e.g. the age at which half of the brood has become vulnerable to fishing, plotted against the abundance of the stock that produced them (Ricker, 1975). Also called reproduction curve.

recruitment level = the ultimate number of a specific year class that survives to attain sexual maturity and joins the reproductive population.

recruitment overfishing = the rate of fishing above which the recruitment to the exploitable stock becomes significantly reduced. This is characterized by a greatly reduced spawning stock, a decreasing proportion of older fish in the catch, and generally very low recruitment year after year. May lead to stock collapse if prolonged and combined with poor environmental conditions. This may take 20 years or more to recover. Species like sharks which produce few young are very vulnerable to recruitment overfishing. In species like cod, the number of spawners has little effect on recruitment as long as there is a minimum spawning stock biomass (cod release far more eggs than ever survive so a few fish can support good recruitment).

recruits = the new age group of the population entering of the exploited component of the stock for the first time or young fish growing or otherwise entering that exploitable component.

rectal gland = an evagination of the terminal portion of the intestine of Elasmobranchii. Function formerly thought to be related to digestion or excretion, but now considered to secrete high concentrations of excess sodium chloride. Found also in the coelacanth Latimeria chalumnae.

rectal valve = a thin diaphragm located in the posterior fifth of the intestine of some Centrolophidae, e.g. Seriolella punctata, Schedophilus huttoni and Psenes pellucidus, or in others a sphincter-like constriction, e.g. Seriolella brama. A deep purple fluid was confined to the valve in S. punctata, but was found throughout the intestine in the other two species referred to. The fluid might be used to void a coloured cloud to distract or deter a predator.

rectangular drainage system = a system of streams arranged around faults in the ground. See also annular, dendritic, deranged, parallel and trellis drainage systems.

rectilinear = straight-lined.

recto = any odd-numbered page of a book, on the right. Opposite of verso.

rectus abdominus = muscle along the mid-ventral line of the abdomen with longitudinal fibres.

recurved = curved upward, backward or inward.

red =raith.

red body = gas gland (a structure with numerous blood vessels (retia mirabilia) in the gas bladder that secretes gases from the blood. Also called fascis mirabilis).

red caviar = caviar made from salmon eggs.

Red Data Book = list of threatened and extinct species for a given country.

red feed count = a condition found in capelin that feed on plankton in or near the harvesting season, leaving them with a reddish coloration, unsuitable for marketing in Japan (Newfoundland).

red fish = male salmon, from their red colouration (Scottish dialect).

red fisher = a fisherman for salmon on the Scottish Tweed River.

red gland = gas gland (a structure with numerous blood vessels (retia mirabilia) in the gas bladder that secretes gases from the blood. Also called fascis mirabilis).

red herring = 1) a strongly salted and cold smoked unsplit whole herring. Smoking lasts 2-3 weeks until the fish is hard. Also called hard smoked herring.

red herring = 2) a diversion intended to distract attention from the real issue (herrings are reddish when smoked and odiferous, and have been used to lay false trails in fox hunting and by escaping criminals trying to confuse pursuing bloodhounds).

red muscle = dark meat (muscle from just under the skin on each side of a fish that is darker and richer in fat than other flesh. Also called blood meat, brown muscle, dark muscle, red muscle).

red pest = Hitra disease (a disease of farmed Atlantic salmon among others caused by certain Vibrio species active at temperatures below 10°C and producing muscular and myocardial degeneration. Red or bloody streaks appear on the body and fins and can lead to fin and tail rot with, in severe cases the tail and/or fins falling off. Also called coldwater Vibrio). See also bacterial haemorrhgaic septicaemia and pike pest.

red sore disease = a disease caused by a ciliated protozoan (Heteropolaria sp.) exhibiting as ulcers or cotton-like growths on the skin, scales and fin spines causing a red lesion, and also found on eggs. Also called "epistylis" after another genus of protozoans.

red tide = a population explosion in marine plankton such as dinoflagellates that is toxic and fatal to fish. The colour of the tide can be red, pink, yellow, green, blue, purple, black or brown. See also brevetoxin.

red worm = a type of worm used as bait in angling.

redd = the nest made by a salmonid comprising a hollow in the stream gravel, where eggs are laid and fertilized, and covered with gravel. The buried eggs are oxygenated by the current, e.g. in Petromyzontidae and Salmonidae.

redd count = the count of number of redds in a river as identified by shape, size and colour, used to compare the relative magnitude of spawning activity between years.

redefinition = emended diagnosis (change in the scope of application of a name, involving a change in the diagnosis (q.v.) of the taxon. Not the same as emendation (q.v.)).

redeposition = in taxonomy, the transfer of a taxon to a new position with or without a change in the name.

redescription = a more or less complete statement of the observed characters of a taxon, without any special emphasis on those which distinguish it from other closely related taxa, including new or altered information to that usually given in the description.

redfish oil = "ocean perch" (Sebastes spp.) oil used to tan leather, as a base for paint, for softening horses' feet, as a rust inhibitor, and for tools on oil rigs. Also reputedly poured on rough seas to calm them!

redhorse = a member of the genus Moxostoma in the family Catostomidae, large freshwater fishes of North America with about 10 species, large in size and with reddish fins.

redmouth disease = a bacterial infection with Aeromonas hydrophila. See bacterial haemorrhagic septicaemia and pike pest.

redox potential = reduction-oxidation potential of water, giving an indication of how well an aquarium would support life. It refers to an electrical charge on a molecule that has transformed in a chemical reaction. The redox potential can be altered by the use of ozone and redox additives.

reduced = a less-developed condition of character.

reduction = 1) a decline in the number of mature individuals of at least the amount stated over the time period specified, although the decline need not still be continuing. Not necessarily part of a natural fluctuation.

reduction = 2) the conversion of fish flesh into products by grinding, rendering, extracting and other processes, e.g. such products as animal, feed, fertiliser, oil.

reduction in status = see status.

reduction fishery = reduction industry.

reduction industry = the process and manufacture of products from fish flesh such as meal and oil, e.g. oil extracted from menhaden used in production of linoleum, health products, etc.

reef = 1) a deposit of skeletal carbonate material forming a complex and varied habitat for fishes and other marine life.

reef = 2) a ridge of rocks or sand lying near the surface.

reef aquarium = a fish tank with live corals and associated invertebrates, meant to showcase these organisms rather than any fish that may be included.

reef base = the area below the consolidated slope extending up to 1 km but no deeper than 50 m. Also called talus slope.

reef block = a large, isolated rock section that has been displaced (usually by storm waves) from the reef or the bedrock.

reef breakwater = a rubble mound of stones of uniform size with a crest at or below sea level which is re-shaped by waves.

reef complex = the entire reef structure, including reef surface, lagoon deposits and off-reef deposits.

reef crest = the sharp break in slope at the seaward margin or edge of a reef flat.

reef drag seine = similar to a beach seine with the float line submerged, fished on reefs and continually unsnagged by divers. Also called reef seine.

reef face = reef front.

reef fish = fish that live on or around reefs, e.g. groupers, grunts, porgies, snappers, etc.

reef flat = the area between a fringing reef and the shoreline. Covered by water at high tide but has little or no water at low tide.

reef front = the outside or seaward edge of a coral reef where diversity of habitat for fishes is greatest. Also called reef slope.

reef mound = a structure that lacks reef characteristics, such as diversification and domination stages.

reef net = a square set net used between reefs, anchored, with fish guided into the net by leads of rope, operated by two canoes, and the weighted lead line raised quickly to the surface to entrap the fish.

reef rubble = an accumulation of dead coral pieces, often colonized with macroalgae. Often found landward of well-developed reef formations.

reef safe = fishes deemed safe to introduce to a marine aquarium, these being species that do not consume other fishes or invertebrates, or aggressively compete for territory.

reef seine = reef drag seine.

reef slope = the reef seaward of a reef crest.

reef system = a cluster of reefs.

reef tank = reef aquarium.

reef top = the area comprising the reef flat and reef crest.

reeklin = the flesh of halibut cut into strips and dried in peat smoke (Scottish dialect).

reel = winder consisting of a revolving spool with a handle, attached to a fishing rod; cylindrical device attached to a fishing rod to let out or wind up the line.

reel line = the line wound on an angler's reel.

reel seat = the are behind the grip on a fly rod where the reel is attached.

reen = a deep drainage channel. A dialect word of Wales. Spelled rhyne in southwest England.

reenge = to agitate water to drive fish out of hiding places (Scottish dialect). Also spelled reinge, ringe and rynge.

reesh = reest.

reest = to smoke or cure fish (and meat) (archaic).  Also spelled reist, riest, reast, rest, rist and reesh.

reeve = attach or interweave a fish onto a sharp stick (Newfoundland).

reeving string = a draw string around a net, e.g. a castnet.

reference = a bibliographic source usually comprising author, date, year, title of article or book, name of journal, place of publication, volume, issue and pagination, or name of publisher, place of publication and pagination.

reference level = a particular level of an indicator, e.g. of fishing effort, fishing mortality or stock size, used as a benchmark for assessment and management performance.

reference plane = the plane to which sounding and tidal data are referred.

reference point = 1) a particular state of a fishery indicator corresponding to a situation considered as desirable, e.g. target reference point, TRP, or undesirable and requiring immediate action, e.g. limit reference point, LRP and threshold reference point, ThRP.

reference point = 2) a specified location to which measurements are referred.

reference station = 1) a tide or current station for which tidal or current constants have previously been determined and which is used as a standard for the comparison of simultaneous observations at a second station.

reference station = 2) a station for which independent daily predictions are given in the tide or current tables from which corresponding predictions are obtained for other stations by means of differences or factors.

referral = transfer of a subordinate taxon from one taxon to another, e.g. species removed from one genus and referred to another, genus removed from one family and referred to another.

reflex strike = a bite by a fish that was not feeding but reacted to the movement or noise of a passing lure.

reflexed = bent or turned backwards.

refreezing = freezing fish after it has been thawed or partially thawed, as in tempering, q.v.

refreshed = 1) refrozen.

refreshed = 2) frozen then thawed.

refrozen = fish frozen at sea then thawed for processing onshore and then re-frozen. Also called twice-frozen or double-frozen.

refuge = 1) a part of the range of a stock which is not accessible to fishing and therefore enables a species or stock to survive higher fishing levels outside the refuge.

refuge = 2) in aquaria a compartment within the main tank or a separate container using water taken from the main tank. Protects fish from predation.

refugia = plural of refugium.

refugium (plural refugia) = 1) an isolated locality often surrounded by a different climate or habitat; often a centre for relics; a refuge in which organisms survived during glaciation, having escaped major climatic change.

refugium (plural refugia) = 2) water where threatened fishes are stocked for safe-keeping.

refusal = the International Commission on Zoological Nomenclature may refuse to use its Plenary Powers in any given case proposed to it. In such a case the Opinion (q.v.) rendered is to specify the name(s) to be used in the case in question, and the action (if any) to be taken.

refuse cod = dried and salted cod below the grade suitable for sale (merchantable cod).

regenerated scale = a replacement scale.

regime shift = a medium- or long-term shift in environmental conditions that impacts the productivity of a fish stock.

regio occipitalis = occipital region (the posteriormost part of the neurocranium, comprising the exocciptals, basioccipital, occipital, dermosupraoccipital and supraoccipital bones, enclosing a large part of the brain and the membraneous labyrinth and connecting to the vertebral column).

regio orbitalis = orbital region (the head around the eye comprising such dermal bones as the antorbital and infraorbitals (bearing a sensory canal) and the suborbitals and supraorbitals (without a canal)).

regio otica = otic region (the skull area containing hearing and equilibrium organs and including endochondral bones (autosphenotics, autopterotics, opisthotics, epiotics), dermal bones (intercalaries, pterotics) and mixed origin bones (sphenotics, prootics)).

registrar = the person in a museum charged with the responsibility for the development and enforcement of policies and procedures related to the acquisition, management and disposition of collections. The registrar maintains records and arranges accessions and loans.

registration = the process of maintaining a means of identifying a specimen(s) for which a museum has permanent responsibility; the overall functions of the registrar.

regression = gradual contraction of a shallow sea so land emerges and rivers are extended either from a sea level fall or land level rise.

regulation = 1) a legal statement affecting fishing.

regulation = 2) controlling the flow of a river.

regulative capacity = a population’s tendency to revert towards some typical average level of abundance rather than to increase or decline indefinitely or to drift aimlessly. Also called homeostasis.

regulated fishery = any fishery with a management plan in place to maintain maximum sustainable yield.

regulative capacity = the tendency for a population to revert to a typical average number of individuals rather than to decline or increase.

regulatory amendment = an option for a fishery manager to make regulatory changes to a fishery management plan. Requires some public input but is not a full amendment.

regulatory discard = a fish thrown overboard because of the regulations as to size or species allowed to the fishery.

rehabilitation = restoration of fish stocks lost by natural or man-made events.

reinge = reenge.

reiniform = kidney-shaped.

reinstate = with reference to a name previously rejected as being a junior secondary homonym: to treat it as a valid name if the conditions of the International Code of Zoological Nomenclature are met.

reintroduction = establishing a species in waters where it has been lost, primarily for conserving the species, not to support a fishery.

reist = reest.

reister = a smoked salmon or other fish (Scottish dialect).

reject = in taxonomy, to set aside the name of a taxon in favour of another name, or to set aside a work that must not be used for nomenclatural purposes.

rejecta = egesta and excreta, both q.v.

rejected name = a name which, under the provisions of the International Code of Zoological Nomenclature, cannot be used as a valid name and which is set aside in favour of another name; a name which, as a matter of taxonomic judgment, is either treated as a junior subjective synonym of a name used as valid or is believed not to be applicable to the taxon under consideration.

rejuvenated river = a river with a gradient that is raised by the earth's movement. See also youthful, mature and old rivers.

rek = raik.

relatedness = sharing of a more recent common ancestor by two clades than they do with any other clade.

relative abundance = an index of fish population abundance used to compare fish populations from year to year. This does not measure the actual numbers of fish, but shows changes in the population over time.

relative conversion rate = quantity of food distributed divided by total production of fish in aquaculture. Dependent on food distributed but also on stocking density, health of fish, age class, competition, feeding methods, environmental conditions, etc.

relative fecundity = the number of eggs per unit weight of fish.

relative fishing power = the relative vulnerability of the stock to different boats or gears. Usually determined as the catch taken by the given apparatus, divided by the catch of a standard apparatus fishing at nearly the same time and place.

relative weight = a body condition index; from the measured weight of an individual fish (times 100) divided by a standard weight for the species at that length. Standard weight is the 75th percentile of the weights of a given species within specified length increments. Abbreviated as W_r.

release = 1) returning a fish to the water after capture, usually in a sport fishery, with as little damage as possible.

release = 2) a collective noun (a noun that denotes a collection of persons or things regarded as a unit) for anglers (coined as a joke).

releaser = the stimulus that starts an innate behaviour pattern, e.g. courting behaviour in a male stickleback is instigated by the releaser of a silver colored female (or model) with a swollen abdomen. Also called sign stimulus.

releasing stimulus = a stimulus which causes the female to shed her eggs.

reliability = the extent to which a resource, if managed properly, can be depended on to provide a reasonably constant yield. An unreliable resource is one that may fail but not through fishing.

relic = relict.

relict = 1) survivors of a formerly widespread fauna existing in certain isolated areas or habitats.

relict = 2) a phylogenetic relict, a form in an otherwise extinct taxon, e.g. Latimeria chalumnae.

remora = 1) a member of the family Echeneidae, in legend able to impede or even stop ships.

remora = 2) a hindrance or drag.

remora fishing = a captured remora is released from a boat with a line attached through its tail or to a ring through the tail. The remora then attaches to a turtle or shark which can be pulled to the boat and speared. The technique is known from the Caribbean to east Africa and China and Australia. This temporary attachment of one animal to a faster one is called phoneses. Also called sucker fishing.

remote site incubator = a lightweight, dark-colored, plastic barrel using a plastic substrate as a hatching medium. Used to incubate up to 125,000 salmon eggs.

remotely operated vehicle = a vehicle that dives in deep water to film deepsea organisms such as fishes. It is controlled from onboard ship and carries no passengers. May be equipped to capture fish or lay traps. Abbreviated as ROV.

removals = all of the fish removed from a stock by fishing, including the catch and any fish killed but not caught.

renal = pertaining to the kidney.

renal corpuscle = the kidney unit consisting of a glomerulus in a Bowman's capsule.

renal vein = paired veins draining the kidneys into the posterior cardinal veins, q.v.

renal-portal system = a circulatory system found in fishes and other vertebrates (except mammals) where blood leaving the tail passes through a venous capillary system associated with the kidneys before entering the heart.

reniform = kidney-shaped.

rensei-hin = inclusive term meaning the products made from kneaded fish meat, e.g. kamaboko (q.v.). Also called nerisei-hin.

rent = the difference between the total revenues obtained from the fishery resource and the total costs of production.

repack = 1) removal of cured fish from the original curing salt, and washing and packing in barrels into which salt and/or saturated brine are added.

repack = 2) herring which did not pass inspection until repacked.

repatriation = the return to a place normally inhabited.

repile = the rearrangement of salted fish piles by putting top layers on the bottom and bottom layers on the top.

replacement bone = endochondral bone.

replacement name = replacement name (a new name (nomen novum) published or an available synonym adopted to replace an earlier name, and valid only if the latter is preoccupied; commonly applied to substitute names proposed to replace junior homonyms). See also nomen substitutum.

replacement scale = a scale which has formed in the place of a lost scale. The centre portion of a replacement scale is equal in size to the one lost but lacks ridges and radii. Not useable for aging purposes. Also called macrocentric, regenerated or latinucleate scale.

replacement yield = the amount of yield in weight that can be removed from a population of fish without leading to biomass increase or decline. Replacement yield is high when population productivity is high under proper exploitation and it is low when the population is underexploited or overexploited. If yield taken is equal to the replacement yield, then the biomass will not change from year to year.

reported species = an introduced organism collected without evidence of reproduction.

reprint = a printed copy of an article in a serial publication or in a separate work, intended for distribution subsequent to the publication of the work that contains it; the text is identical with the original, but there may be changes in headings, pagination, or page arrangement. Also called separate or separation. See preprint.

reproduction curve = a graph of the progeny of a spawning at the time they reach a specified age, e.g. the age at which half of the brood has become vulnerable to fishing, plotted against the abundance of the stock that produced them (Ricker, 1975). Also called recruitment curve.

reproductive drain = the theory that growth and reproduction in fishes are antagonistic. Females would grow less than males because of their greater investment in egg production compared to that required for sperm production in males. Generally not true as many fish females are larger than males.

reproductive guild = a group of unrelated fishes with a similar form of reproduction, e.g. on substrates such as rocks and gravel (lithophil), in open water (pelagophil), on plants both living and dead (phytophil), on sand (psammophil), in holes and crevices (speleophil) and various (polyphil); or by behaviour such as external bearers (mouth brooding), internal bearers, guarding or non-guarding, hiders, nest builders, scatterers, etc. See reproductive style.

reproductive isolation = the inability of two or more groups of organisms to interbreed, either because of inherent or external reasons (e.g. different behavior, a geographic barrier). Inherited reproductive isolation is the basic criterion of species.

reproductive potential = potential number of a species that will attain maturity from the spawning of each adult.

reproductive products = roe and milt.

reproductive style = the methods of reproduction seen in fishes have been summarised in Balon (1990). Three ethological sections are nonguarders, guarders and bearers. Nonguarders produce eggs which are scattered into the water (reproductive guilds pelagophils, lithopelagophils, lithophils, phytolithophils, phytophils, psammophils and aerophils, all q.v.) or egg broods which are hidden (reproductive guilds aeropsammophils, speleophils, lithophils, ostracophils and xerophils, all q.v.). Guarders include clutch tenders (reproductive guilds pelagophils, aerophils, lithophils and phytophils, all q.v.) and nesters (reproductive guilds aphrophils, polyphils, lithophils, ariadnophils, phytophils, psammophils, speleophils and actiniariophils, all q.v.). Bearers include external brooders (reproductive guilds transfer brooders, auxiliary brooders, mouth brooders with and without buccal feeding, gill chamber brooders and pouch brooders, all q.v.) and internal live bearers (reproductive guilds facultative and obligate lecitrophic, embryonic cannibal, histotrophic, placentotrophic and combined live bearers, all q.v.).

research collection = a collection of museum specimens meant to be worked on by a researcher; there may be restricted access until the material has been fully worked up and it may then be added to the museum's primary collection or the material may be valuable scientifically but of poor quality or of uncertain ownership and not meant for eventual deposition in the primary collection.

reserve = a part of a quota set aside at the beginning of the fishing season to allow for uncertainties in estimating the catch.

reservoir = an area behind a dam where water is collected and stored for later use. May also include a natural water body used for control.

reservoir host = a fish that serves as a source of infection for other organisms by harbouring infections and parasites.

resident = refers to non-migratory fish, usually salmonids. May refer to fish that remain within a circumscribed area.

residuals = members of a generally anadromous species which do not migrate but remain in fresh water and do not spawn, e.g. in Oncorhynchus nerka; a juvenile that matures sexually before it smolts and goes to sea.

resilience = 1) capacity of a natural system such as a fisheries community or ecosystem to recover from heavy disturbance such as intensive fishing.

resilience = 2) a measure of how much disturbance can be absorbed before the ecosystem changes.

resorption = the loss of calcified material through a physiological process. Found in scales for example.

resource = a fishery resource is those natural components of value to a fishery, i.e. fish.

resource rent = the value to fishers of the fish in the water before they are caught. It is usually a large component of the economic rent.

resource user = any user of a fishery resource, e.g. a holder of a commercial licence, a quota holder, an aboriginal group with a communal licence, a processor who holds a fishing licence, a recreational fisher, an aquaculturist who uses wild fish stocks.

response error = errors in angler surveys caused by faulty memory, exaggeration, rounding bias, lying, misunderstood questions, misidentified species or incorrectly measured fish.

responsible fishery = the sustainable utilisation of fishery resources in harmony with the environment.

rest = reest.

rest line = a line of discontinuity within a tissue such as bone, corresponding to a temporary but complete cessation of growth.

resting egg = a fish egg that has entered a state of slowed or stopped development. May refer to eggs in diapause or those with slowed, but not the arrested, development typical of diapause.

resting stage = the period in larval development between hatching and active feeding.

restocking = adding fish as young or adults to a water body where they are few in numbers to support a fishery.

restoration = re-establishment of fish stocks lost from, or reduced in, an area through overfishing or pollution.

restricted (morphologically) = reduced, e.g. gill openings restricted (reduced in size).

retained catch = that part of the total or gross catch that is not discarded. See also total catch.

retaliator = said of fish that will only attack if accidentally disturbed or deliberately provoked.

retardation = the amount of time by which corresponding tidal phases grow later day by day (about 50 minutes).

retarding reservoir = a reservoir for temporary storage of flood water. Also called detention dam or reservoir.

retention = 1) the probability of a fish encountering a fishing gear and being retained by it after coming in contact with it. Often expressed as a function of size or age (retention curve).

retention = 2) pertaining to a character retained in an evolutionary sequence, either primitive or derived.

retention basin = a wetland or excavated basin constructed to contain excess rain or runoff, especially in urban developments where water cannot be easily absorbed into the ground. Some drain quickly and support no fish life, others have a permanent central area conducive to fish. See also detention basin.

retention curve = relationship between the size or age of a fish and its probability to be retained by the fishing gear after encountering it.

retention pond = retention basin.

retention time = the average length of time water resides in a lake. May be a few days in a small artificial impoundment to many years in large seepage lakes. Long retention times result in greater recycling and greater nutrient retention with consequent effects on the fish fauna.

retia mirabilia (singular rete mirabile) = the clump of parallel arterial and venous capillaries which supplies the gas gland with blood and is found on the outside of the gas bladder. Also a heat exchanger in Scombridae.

retiarii = plural of retiarius.

retiarius (plural retiarii) = a net man or Roman gladiator using a net or rete, hence the name, a trident and a dagger, equipment resembling that of a fisherman. He lacked armour, except for a shoulder guard protecting the face and neck and fought naked.

reticle = graticule (a network of fine lines, dots, cross hairs, or wires in the focal plane of the eyepiece of an optical instrument. Used to measure the size of such objects as eggs of fishes. Also called reticule).

reticulated = with a network, e.g. lamellae of gills of Acanthocybium (Scombridae).

reticulation = 1) network pattern, e.g. reticulations in a colour pattern.

reticulation = 2) joining of separate lineages on a phylogenetic tree through hybridisation or lateral gene transfer.

reticule = graticule (a network of fine lines, dots, cross hairs, or wires in the focal plane of the eyepiece of an optical instrument. Used to measure the size of such objects as eggs of fishes. Also called reticle).

retina = that part of the eye developing from the optic primordium; includes the neural retina and the retinal pigment layer and is continuous with the optic nerve.

retinal pigment layer = a single-cell layer of pigmented epithelium covering the neural retina and developing from the outer of the two layers of the optic cup.

retractor dorsalis = muscles associated with the pharyngeal jaws and used in swallowing food.

retrieve = 1) recovering line cast out while fishing.

retrieve = 2) various ways of working or fishing a lure.

retrieve = 3) a descriptive term for a type of fly reel, whether it has a left or right hand retrieve.

retro- (prefix) = backwards.

retroarticular = the triangular, endochondral, dermal or mixed origin bone on the back, hind corner of the lower jaw. Often called the angular, Bridge's ossicle a, lower articular or angulo-retroarticular.

retrograde = said of a structure that is located farther back than is typical of the group.

retronym = a modification of an existing word occasioned by a discovery or a new concept, e.g. herring became Atlantic herring once Pacific populations were determined to be a distinct species.

retroperitoneal space = the space behind the peritoneal cavity, housing the kidneys.

retrorse = bent or turned backward or downward.

retrospective pattern = this pattern indicates that model estimates for the most recent years change substantially and systematically as new years data is added. This indicates a potentially serious bias in stock assessment.

revalidated name = a name published before the starting date of a group but subsequently validly published.

reversal = change of normal symmetry, where dextral species occasionally produce sinistral individuals or vice versa. The reversal occurs in the eyes, head and epidermal features but does not affect the visceral organs.

reverse cast = casting across the body on the off-hand side of the stream in nymphing (the right side of the stream for a right-handed angler, and vice versa). Also called western roll cast.

reversed = a hook offset to the left when viewed from the top of the hook with the eye towards the observer, cf. kirbed. A hook that is not offset is called straight.

reversibility = the extent to which a change in a stock or ecosystem induced by exploitation will reverse itself when the causative factor is removed.

reversing falls = a name applied to falls which flow alternately in opposite directions in a narrow channel in the St. John River at St. John, New Brunswick; caused by a reversing tidal current.

reversing tidal current = a tidal current that flows in opposite directions with a slack water at each reversal of direction. Usually found in rivers and straits which have restricted channels.

revetment = structures built along river banks to prevent erosion, such as a stone facing or a retaining wall.

revision = a critical re-appraisal of a taxon systematically.

revisor, first = the person who first selects one of two or more simultaneously published names that (s)he believes represent the same taxon, or who selects which one of two or more taxa for which identical names have been simultaneously published, the name will apply to. This is done in the interest of nomenclatural stability.

revolving-spool reel = bait casting reel (a fishing reel in which the spool is not stationary during a cast but revolves).

rhabdoid = rod-shaped.

rheo- (prefix) = current, flowing.

rheocrene = a spring producing running water in the form of a stream.

rheokinesis = movement in relation to water currents.

rheophilous = having an affinity for, or thriving in, flowing water

rheophobous = intolerant or flowing water.

rheoplankton = the plankton of running water. Also called potamoplankton.

rheoreceptor = current receptor - lateral line organs.

rheotaxis = orientation to water currents. Positive rheotaxis means facing upstream, negative rheotaxis oriented downstream.

rheotropic = responsive to a current.

rhinal = related to the nose.

rhino rig = a fishing rig with two boilies, q.v., on a pop-up on the normal hair and a normal bait on an extra hair from the eye of the hook facing the wrong way.

rhinosphenoid = a small plate-like median bone forming a septum between the olfactory nerves as they issue from the orbitosphenoid, e.g. Characoidei such as Iotabrycon, Rhaphiodon.

rhipidion = the distal opening of the tube formed by the claspers when held together. Fan-shaped for dispersing sperm in a radiating spray during copulation.

rhipidocercal = tail of expanded, fan-shaped form (as opposed to one of tapering form or oxycercal), e.g. in Polyodon.

rhipidoid = fan-shaped.

rhithral = adjective for rhithron.

rhitrhral zone = the upper reaches of a river characterised by well-oxygenated water, low temperatures (less than 20°C), fast and turbulent current, clear water and a bottom of large-sized sediment.

rhithrocoa = the biotope and biocenosis of the rhithral zone.

rhithron = the organisms inhabiting the rhithral zone. upper reaches of a river characterised by well-oxygenated water, low temperatures (less than 20°C), fast and turbulent current, clear water and a bottom of large-sized sediment.

rhizobenthos = organisms rooted in the substrate and well extended into the water column.

rhombencephalon = the hindbrain, the rearmost part of the developing brain. The rhombencephalon divides into the metencephalon (anterior) and the myelencephalon. Details of the brain structure of a fish (Danio rero) may be found in Wullimann et al. (1996). See also brain.

rhombic scale = rhomboid scale.

rhomboid = diamond-shaped.

rhomboid scale = ganoid scale (a non-overlapping or partially-overlapping scale, often rhomboidal in shape, with thick outer ganoine layer (enamel-like substance), a middle layer of dentine and an inner dermal, cosmine bony layer. Grows by addition of material above and below, e.g. in Lepisosteidae, Amiidae and Polypteridae. Lepisosteidae have lost the dentine layer. The scales of Lepisosteidae are called lepisosteoid scales as distinct from paleaoniscoid scales of Brachiopterygii).

rhomboidal = shaped like a rhomboid - a non-rectangular parallelogram; wedge-shaped. Said of a caudal fin that has the middle rays longest and the fin sides roughly straight.

rhombomere = the hindbrain segment or neuromere.

rhyacium = a torrent community.

rhyacophilous = torrent-loving.

rhymes = see under Quotations as the the letter Q lacks piscine entries.

rhynchichthys = the late postlarval stage of Holocentridae characterised by the presence of rostral, preopercular, opercular and supraoccipital spines and a silvery colour.

rhyne = a deep drainage channel. A dialect word of southwest England. Spelled reen in Wales.

rib = one of a series of long, thin bony rods articulating with the apophyses of the vertebrae and supporting the trunk musculature. The ventral ends are free. They consist of two types: the dorsal, epipleural or true ribs which arise from the transverse processes and lie in the transverse septum of the epaxial muscles (homologous to those in tetrapods) and the ventral, pleural, or pleuroperitoneal ribs which lie just outside of the body cavity. Pleural ribs are found in Elasmobranchii, pleural and dorsal ribs in Teleostomi; ribs are lacking in Holocephali. The intramuscular bones of the horizontal septum are homologous with dorsal ribs. Haemal ribs (q.v.) is a misnomer for the ventral ribs.

rib wall = an artificial structure across a stream below a dam or weir used to raise the water level; fish can use this in place of a fishway as it slows down water flow.

ribbed = a surface with a series of ridges.

ribbon reef = a large, offshore and linear reef, seaward of a fringing reef, which is elongate but does not form a barrier to the land. Also called shelf-edge reef and sill reef.

ribbon tail = in angling, a plastic worm with a long tail that waggles when retrieved.

ribline = a heavy line or chain running the length of a trawl net to add strength.

rice paddy = a field for growing rice, flooded with water and often stocked with fish. See paddy-cum-fish culture.

rice the water = to throw plants and branches into a river in order to frighten salmon before using a spear or leister. The effect is to stupefy the fish so they lie motionless.

richness = the total number of species in a unit area. May be expressed as the number of species divided by the total number of individuals.

rick = to hook or pierce a fish.

Ricker curve = named for William Ricker, a Canadian fisheries biologist, this is a mathematical model of fish population dynamics. A graph of mature progeny and spawners is used to determine average maximum catches for a fishery. One line on the graph is the line of natural replacement where spawners are replaced by an equal number of progeny. The natural equilibrium point is where spawners equal progeny without fishing. Past this point crowding is a factor depressing the numbers of fish through egg loss on spawning beds. A curved line shows the maximum sustainable catch (see Ricker (1975) for details).

rictus = 1) the junction of the premaxilla and maxilla; the corner of the mouth in fishes.

rictus = 2) the expanse of an open mouth, generally.

rictus = 3) a gaping grimace, usually in humans.

rid = redd.

riddles:-

1) = the tail of the beaver was classified as fish in the Middle Ages, giving rise to the riddle "What swims like a fish, tastes like a fish, is a fish, and yet is not a fish?".

2) = Alive without breath,
       As cold as death;
       Never thirsty, ever drinking,
       All in mail never clinking.

Answer: fish (from "The Hobbit" by J. R. R. Tolkien).

3) = 1. In a street there are five houses, painted five different colours.
        2. In each house lives a person of different nationality.
        3. These five homeowners each drink a different kind of beverage, smoke a different brand of cigar and keep a different pet.

The question: who owns the fish?

Hints

1. The Briton lives in a red house.
2. The Swede keeps dogs as pets.
3. The Dane drinks tea.
4. The Green house is next to, and on the left of the White house.
5. The owner of the Green house drinks coffee.
6. The person who smokes Pall Mall rears birds.
7. The owner of the Yellow house smokes Dunhill.
8. The man living in the centre house drinks milk.
9. The Norwegian lives in the first house.
10. The man who smokes Blends lives next to the one who keeps cats.
11. The man who keeps horses lives next to the man who smokes Dunhill.
12. The man who smokes Blue Master drinks beer.
13. The German smokes Prince.
14. The Norwegian lives next to the blue house.
15. The man who smokes Blends has a neighbour who drinks water.

Answer: The German.

4) = What has cities, but no houses; forests, but no trees; and water, but no fish? Answer: a map.

ridge = the line or elevation separating two river systems.

riest = reest.

riffle = a shallow stream habitat with broken or choppy surface water and moderate to fast current. Gradient is about 1-4%.

rift = a shallow or rocky place in a stream, forming a ford or rapids.

rig = 1) the arrangement of fishing gear, the style varying between species sought. Refers to the terminal tackle (hooks, lures, etc) but may also refer to an outfitted boat. Used in both angling and commercial fishing. Angling rigs have various storage containers for transport and protection including rig bins (a round, plastic screw top container with a foam insert attached to the the middle of the lid - the rig is wound around the foam) and rig pouches (a wallet with a zipper around three sides containing plastic sleeves to place rolled up rigs in).

rig = 2) arranging the fishing gear of a rig.

rig = 3) the backbone or spine of an animal, including fish (Scottish dialect).

rig tube = silicone rubber or shrink tubing surrounding an angling rig to protect the line from sharp rocks and from becoming tangled.

right = a right to catch a specified quantity of fish, a proportion of the total allowable catch, to use a boat or any other specified fishing equipment, in a manner specified in a management plan or in fishery regulations.

right bank = the right side of a river when facing downstream.

rigor mortis = literally the stiffness of death; in fish occurring about 8-24 hours after death and resolving after about 1-3 days, varying by species, ambient temperature, nutritional status, amount of exercise by fish before death, etc.

rill = a creek, a small brook, a rivulet.

rille = rill.

rim control reel = a fishing reel with part of the spool exposed so that the angler can control drag by touch.

rin snips = to divide profits equally as in a fish catch among the crew (Scottish dialect).

rind = a large piece of bark from a fir tree used to cover fish piles in Newfoundland.

ring = 1) the British word for the North American term guide, the series of rings along a fishing rod through which the line feeds.

ring = 2) circles in the water caused by a rising and feeding fish.

ring = 3) a region of similar structure or optical density laid down during growth of hard parts used in ageing. Also called band, mark and zone.

ring of the fisherman = a gold papal seal used on documents and placed on the new pope's finger by the cardinal camerlengo. It has a representation of St. Peter fishing in a boat with the new pope's name around it.

ring intestinal valve = an intestinal valve with a radius lower than that of the gut so the valve is internally open and some food can pass through without coming in contact with the valve.

ring net = a modified lampara net with purse rings operated by two vessels (a lampara net is similar to, but much smaller than, a purse seine with no pursing action used for catching schools of small fish attracted to lights, e.g. anchovy and pilchard. There is a central spoon-shaped section and two lateral wings and the net is usually operated from a small boat. The rapid retrieval of the lead line does close the bottom of the net but it is not a true purse).

ring trawl = a coarse mesh plankton net used to collect fish larvae.

ring worm = in angling, a plastic worm with ridges said to be life-like to fish.

ringe = reenge.

ringer = 1) a dead fish embryo characterised by a dark central area and a light rim of germ cells. Used in hatcheries to pick out and discard dead embryos.

ringer = 2) a fisherman using a ring net.

rings = circular structures on scales and bones laid down annually and indicative of age and growth.

rip = 1) a stretch of broken water in a river.

rip = 2) a narrow band of current, flowing seaward through the surf.

rip = 3) the process of cutting open a fish from under the lung bones to the vent, after the throat has been cut.

rip = 4) removing the gills and intestines from herring or mackerel (Newfoundland).

rip = 5) a round pannier or basket, sometimes used in pairs and slung on each side of a horse for carrying loads, such as fish, or individually for coiled fishing lines (Kent and Scottish dialects).

rip current = rip (2).

rip-jigging = jigging in areas with thick vegetation. The jig is allowed to settle in the weeds and then a strong pull rips the jig through them, cutting the weeds, and the process repeated.

riparian = pertaining to lake, river or stream banks.

riparian rights = those rights belonging to a person owning land bordering a watercourse, concerning its bank, bed and waters.

ripe egg = a mature egg.

ripe fish = one which is ready for spawning.

ripening = 1) the process of becoming a ripe fish.

ripening = 2) maturing of small fatty fishes, e.g. anchovies and herring, in salt, sugar and spices in barrels over several months. Proteins and lipids are degraded by enzymes from the pyloric caeca of the fish and a product known as semi-preserves results that must be kept chilled.

ripper = 1) a hook or series of hooks pulled rapidly through the water to impale fish. Fish may also strike at the moving hooks.

ripper = 2) a hard fighting fish that pulls or rips line off the reel.

ripper = 3) a seller of freshwater fish at markets (archaic). The men carried baskets of fish from the coast to inland markets. Also called rippier.

ripper = 4) a sharp knife used to gut or dress fish.

ripper-fishing = fishing for cod where the boat is allowed to drift with the tide from one point to another, the distance between these being termed a scarce.

rippie = a circular net used to poach salmon (English and Scottish dialects).

rippier = ripper (3).

ripping = retrieving a fishing lure fast enough to cause it to splash at the surface. Also called burning or buzzing.

ripping hook = ripper.

ripping side = setting hooks every ten feet on a drifting line intended to snag a fish. Also called sweet jigging.

riprap = large rocks or artificial structures used to stabilise stream banks or protect areas subject to wave action against erosion.

riprap net = a modified bar net with ropes at a diagonal instead of bars (a bar net is a gill net with ropes or wooden bars attached vertically used as a gill net or a trammel net).

rise = 1) the action of a fish coming to the surface to feed. The type of rise (dimpling the water surface, splashing, etc.) can indicate the food item and therefore the type of artificial fly to use.

rise = 2) an increase in the number of meshes per row in making a fish net.

rise end = the rear portion of a cod's vertebral column, curving slightly upwards near the tail (Newfoundland).

rise line = a rope attached to the bottom of the doors of a cod-trap and used to close the entrance before the net is hauled to the surface.

riser = 1) a fish that rises.

riser = 2) in aquaculture, the vertical part of a water controlling device, e.g. a monk, q.v.

riser = 3) rizzer.

rising tide = flood tide (rising or incoming tide; the period between low water and the succeeding high water. Flow enters an estuary during a flood tide).

rist = reest.

rite = properly, correctly, according to the rules.

rival = pertaining to a stream or rivulet.

river = a flow of water in a natural channel, larger than a stream (or a large stream, see stream). Some languages have words for rivers of varying sizes; in English a river can vary from a small water body that can be waded across (especially in deserts) to channels navigable by ocean-going ships. There is no equivalent to fleuve in French which means a very large river usually running into the sea. See also youthful, mature, old and rejuvenated rivers.

river basin = total land area drained by a river and its tributaries.

river classification = rivers or sections thereof are classified by geological aging. Young river sections are usually at headwaters and have low fertility but high oxygen levels, middle-aged river sections are further downstream and more fertile while mature sections are deep, slow-moving, highly fertile and have low oxygen levels.

river continuum concept = the theory describing the physical and biological succession in a river throughout its course.

river development = the degree of departure of a stream from a straight course.

river head = the confluence of a river and the sea.

river kilometre = distance from river mouth or other known locality to a specific site. Abbreviated as Rkm. Note that rkm is the distance between two points along a river.

river mile = distance from river mouth or other known locality to a specific site. Abbreviated as rmi.

river mouth = the outfall of a river.

river plume = river water, often turbid, beyond the estuary or river channel.

river warden = a guardian of the usage of salmon and trout streams under regulatory control.

river-type fish = anadromous fish that live for a year or more in rivers before migrating. See also ocean-type fish.

riverain = pertaining to a river bank or the general vicinity of a river.

riveret = rivulet.

riverhead = the source of a river.

riverine = pertaining to a river, river-inhabiting.

riverkeeper = the lead person in an organisation devoted to the environmental welfare of a particular river. Usually a citizen-based, independent organisation fostering links with community groups, private individuals, scientists, local governments, NGOs, and others.

riverlet = a small stream or brook, though rivulet is more commonly used.

riverside = ground along a river bank.

riving = pushing a pointed rod under one gill cover and out the mouth of a small fish so it cab be carried or hung for smoking.

rivulated = marked by irregular streaks.

rivulet = a small stream or brook.

rizer = rizzer.

rizzar = rizzer.

rizzer = to dry, prtch or cure fish by exposing them to the sun (Scottish dialect).

Rkm = river kilometre ( distance from river mouth or other known locality to a specific site).

rkm = the distance between two points along a river.

roach = 1) the cyprinid fish Rutilus rutilus of Europe.

roach = 2) the upward curve in the foot of a square sail. From the convex profiles of this fish. See also roach-backed and roach-bellied.

roach = 3) used incorrectly for certain North American sunfishes (Centrarchidae).

roach-and-dace = face (rhyming slang). Roach and dace are European cyprinid fishes.

roach-backed = convex in profile, as in the body shape of a roach (Cyprinidae, Rutilus rutilus).

roach-bellied = roach-backed.

road = not usually a habitat for fishes, except possibly walking catfishes, in its terrestrial meaning. The word also means a place where ships can ride at anchor some distance from shore. Usually in the plural and occurs in place names.

roads = plural of road.

roadstead = road as defined above.

robust = strongly or stoutly built, husky; said of fish body shape and form.

robustness = the capacity of a population to persist in the presence of fishing.

rock fishing = the sport of catching fishes from rocks, cliffs and breakwaters, popular where these conditions prevail but often dangerous.

rock salmon = a commercial name for fish sold in fried-fish form in Britain. Used for fish not known to the public or the vendor, of for fish of ungainly appearance or poor reputation. Often a small shark, Squalus acanthias.

rock-hopper trawl = a demersal otter trawl with rubber disks attached to the groundrope and to a second rope off-centre. When the trawl encounters an obstruction on the sea bed, the groundrope and the second rope wind around each other and accumulate tension, eventually when the tension is too high the trawl hops free.

rock-ramp fishway = a structure allowing fish to pass a barrier. Large rocks and timbers are used to build pools and small falls that mimic natural structures. This fishway only works over short distances because of the length of the channel needed for the ladder. See also pool-and-weir ladder, vertical slot fish passage and DeNiel fishway.

rocker bone = a prominent, median, bean-shaped bone in Ophidiidae and Carapidae which is drummed against the anterior end of the gas bladder for sound production. Also called a cuneiform bone.

rockhopper disc = rubber discs cut from old car tyres on the groundrope of a trawl as protection against snagging.

rod = 1) a device to carry and project a fishing line, hook(s) and bait or lures. The construction of rods is both a craft and a science and there is an immense variety of types, often specialised for particular species. Originally made of wood (split cane), now made of fibreglass, graphite/fibreglass or kevlar.

rod = 2) an elongate, rod-shaped cell in the eye sensitive to dim light.

rod = 3) spawn of a fish. Also spelled rodd, roid, rud and rude.

rod = 4) the act of spawning. Also spelled roid and rude.

rod belt = a leather or plastic belt worn on the waist and used to fight large game fish. The rod butt sits in a belt socket and helps fight the fish by relieving strain on the arms.

rod hand = the hand used to hold the fly rod when casting; as opposed to the line hand.

rod holdall = a large waterproof bag with straps for carrying, used to transport rods, poles, ban sticks, etc.

rod holder = a device attached to a boat in which a rod can be placed, especially when trolling large baits.

rod licence = in Britain, all coarse anglers must have an annual or temporary licence.

rod pod = an adjustable metal stand allowing several fishing rods to be set up side by side. It can be set up on uneven ground or on ground that is too hard for banksticks to be pushed in. It has two forked legs joined by a central support bar. A buzz bar can be used in place of the central bar, supporting several rods with bite alarms and swing indicators.

rod rest = a system for holding a fishing rod when engaged in float fishing or ledgering. A metal bar or bankstick is pushed into the river bank and a rod rest is screwed into its top end. The rod rest can be a simple, fixed U- or Y-shape or various adjustable types. May support both the top and butt of a rod. Called sand spike in North America.

rod taper = the taper of a fishing rod determines how it bends, e.g. fast taper rods have their action in the tip, slow taper rods have a through action and compound taper rods show elements of both of these.

rod tube = stiff plastic tubes with caps for storing fishing rods.

rodd = rod (3 and 4).

rodlet cell = a pear-shaped cell with a distinct capsule found in various tissues of fishes but lacking in Elasmobranchii. It has a nucleus at the mid-end and longitudinally oriented rodlets. In epithelia it is oriented parallel to the epithelial cells with the distal end containing the nucleus, distal to the lumen; in connective tissue, no particular orientation has been noted. Has been thought to be a parasite, perhaps a sporozoan, and has even been given a scientific name (Rhabdospora thelohani). But typical nuclear stains do not take in the rodlets, so it seems unlikely that the rodlets are nuclei of a parasite. Tests show the rodlets are protein with varying amounts of attached sugars, probably in the form of a neutral glycoprotein. The function is likely secretory and is perhaps involved in ion transport.

roe = the mass of eggs in the ovary. Soft roe refers to the male gonad, hard roe to the female gonad. Roe may also be used to indicate the female of a species, e.g. roe shad is female, buck shad is male (Alosa sapidissima).

roe bag = fish eggs used as bait for such species as Pacific salmons, enclosed in a mesh bag to keep the eggs together. Also called spawn bag.

roed (adjective) = full of roe.

roen = the roe of fish (Cumberland dialect).

roid = rod (3 and 4).

roll = 1) rotation of a swimmer around its horizontal or anteroposterior axis.

roll = 2) capelin (Mallotus villosus) schooling in inshore waters and being swept onto beaches at high tide when spawning.

roll cast = a fly fishing cast where line is rolled directly off the water; used where a back cast is not possible because of overhanging trees for example.

roll line = a set line on a forked wooden prong, lightly fastened and unrolling easily when a fish bites.

rolled up pickled herring = zavinac, the term used for the @ sign in email addresses in Slovakia and the Czech Republic.

roller = male capelin (Mallotus villosus) at spawning time.

rolling = moving brine containers to prevent fish from sticking together and to evenly distribute salt.

rolling hitch = similar to a clove hitch, q.v., except that is has an extra turn ahead of one of the half hitches. Used to make one line fast to a heavier line. Various websites have animated steps showing how to tie this knot.

rolling leger = fishing with a weigh in running water such that the rig rolls and bounces along the river bed.

rolling splice = a knot used to tie a braided backing line to a fly line. Various websites have animated steps showing how to tie this knot.

rolling stones = a gene name for a zebrafish mutation affecting the ear (loose otoliths). See also einstein, half stoned, what's up, van gogh, among many others.

rollmops = marinated herring fillets wrapped around onion slices and held together with toot picks or cloves. Packed in mild vinegar and acidified brine and with spices and various sauces.

Roman numerals = used in ichthyology to indicate spines as opposed to soft rays in fish fins, and may also appear on older European literature as year of publication:-

I = 1, II = 2, III= 3, IV = 4, V = 5, VI = 6, VII = 7, VIII = 8, IX = 9, X =10, XI = 11, XII = 12, XIII = 13, XIV = 14, XV = 15, XVI = 16, XVII = 17, XVIII = 18, XIX = 19, XX =20, XXI = 21, XXX = 30, XL = 40, L = 50, LX = 60, LXX = 70, LXXX = 80, XC = 90, C= 100, D = 500, M = 1000.

ron = roun.

rone = roun.

roof = netting covering the top of an open cod trap, installed to prevent fish from escaping.

roog = a spawned fish or a poor fish in a catch (Scottish dialect). See also roogie.

roogie = the adjective for roog.

rookie = ruggie.

rookit = a ball of minced fish mixed with breadcrumbs, a rissole (Scottish dialect).

room = 1) fish room or hold (an enclosed space on a vessel for storing fish; may be insulated and/or refrigerated).

room = 2) fish room (a piece of land by the shore from which a fishery was conducted in Newfoundland).

room = 3) fish room (the stages. q.v., flakes, q.v., stores, crew and family housing, and other facilities where a fish catch was landed and processed in Newfoundland).

room holder = occupier of fishing premises or fish room.

roomer = migratory fisherman from Newfoundland who conducts a summer fishery from a room on the coast of Labrador.

root = the non-enameled tooth part, forming the junction with the jaw and providing vascularisation of the tooth (Herman et al., 1994).

root coating = the coating on the upper part of the of the tooth root, usually enameloid in Chondrichthyes (Herman et al., 1994).

root effect = the decreased ability of blood to load oxygen when the carbon dioxide tension is increased (and pH is below a certain value).

root stem = the root part of the tooth in Chondrichthyes between the crown base and the root lobe section (Herman et al., 1994).

rooting = fish feeding by probing the bottom sediments.

rootwad = a mass of roots from a tree that provide shelter and nutrients for a fish.

rope trawl = the netting of the front part of a four-seam trawl made of plaited warps running parallel for a few meters. The aim is to save energy required for towing by decreasing the resistance of the gear. Also called spaghetti trawl.

ropy brine = a defect in brine where the sugar content has been converted to a polysaccharide giving a slimy, stringy consistency.

ros = ross.

Rosa Lee phenomenon = use of comparative specimens of smaller or larger size than the test specimen results in an over-estimation or an under-estimation respectively of the total length of the fish. This influences back-calculation of fish sizes using proportional methods due to changes in relative growth rates. If mortality is higher for larger fish, population size-age relationships (i.e. growth equations) based on a single sample or repeated sampling of a single cohort will underestimate individual growth.

rosary ponds = a series of fish ponds with water flowing from one to the next.

roseate = flushed pink.

rosette = arranged in a fashion resembling a rose; rose-shaped.

ross = keeping a fishing line clear of the bottom by lowering it to the sea floor and then raising it a short distance, or to move it up and down to attract fish (Scottish dialect). Also spelled ros.

rostra = plural of rostrum.

rostral = 1) relating to the snout or rostrum.

rostral = 2) towards the snout or rostrum. usually means anterior.

rostral bar = an anterior extension of the skull in some members of the Rajidae.

rostral bone = 1) the paired superficial dermal bone covering the ethmoid anterior to the eye in Holostei.

rostral bone = 2) a tooth bearing bone modified from an illicium on the tip of the snout of Lynophrinidae.

rostral cartilage = an element in the olfactory region skeleton.

rostral fin = subrostral fin (a shelf-like projection extending forward under the rostrum of Myliobatidae).

rostral fold = a groove between the lip and the snout.

rostral hook = the hooked section of the snout overhanging the mouth in Cynoglossidae.

rostral plate = a small plate on the anterior tip of the snout, e.g. in some Agonidae.

rostral spine = a spine of the rostral plate.

rostral teeth = tooth-like projections on the sides of the snout of Pristidae and Pristiophoridae. They lack a basal plate typical of other elasmobranch teeth and are made of orthodentine and vitrodentine with a pulp cavity filled with osteodentine.

rostral tubule = a network of branching canals which may carry either nerve fibres to surface sensory organs or capillary blood vessels in dipnomorph Sarcopterygii.

rostrum (plural rostra) = 1) any projecting snout or beak.

rostrum (plural rostra) = 2) produced anterior part of the skull, e.g. in Elasmobranchii and Acipenseridae.

rostrum (plural rostra) = 3) the bony shelf overhanging the cavity where the esca of Ceratiidae is housed.

rostrum (plural rostra) = 4) the longer lip of the ostium of the sagittal otolith. Generally longer than the antirostrum.

rot oil = cod liver oil processed by decomposition.

rotational fishery = exploitation by means of alternatively open and closed areas, i.e. high fishing intensity followed by a fishing ban.

rotenone = a fish poison derived from the roots of the jewel vine plant, Derris ellipitca, D. lagensis, D. malaccensis, and D. uliginosa (Leguminosae). Lacepod (Lonchocarpus utilis and L. uruca), the yam-bean (Pachyrhizus erosus) and hoary pea (Tephrosia spp.) are also used. Often used to eliminate unwanted fishes from waters before stocking with game fish and by ichthyologists as a a collecting tool. It acts as a respiratory toxin, adversely affecting mitochondrial action by blocking electron transport - the fish asphyxiate. Available under many trade names. Other piscicidal plant chemicals include callicarpone, huratoxin, ichthyothereol, inophyllolide, juglone, justicidin, maingayic acid, and vibsanine, all q.v.

rotskjae = fish split in two except for a short section of the tail ready for hanging and air drying (Norway).

rotted = cod-liver oil rendered by decomposition of the livers in a barrel.

rotting nose disease = the formation of small, grey, pin-hole abrasions around the nose that eat at the flesh, leave the fish open to secondary infections, and eventually can kill the fish. Attributed to malnutrition and found in ssuch fishes as oscars (the cichlid Astronotus ocellatus).

rouelle = thin slices of fish cut perpendicular to the backbone. Usually mackerel (France).

rough fish = those fish which are not sought for sport or food because of a perceived poor fighting or eating quality.

roughage = in aquaculture, a feed containing a high percentage of indigestible constituents such as cellulose.

roughie = ruffie.

round = a single row of netting going the full extent of the cod trap (Nrwfoundland).

round cure = salt round fish (whole ungutted fish cured with salt). Also called round salted fish, bulk cure, kench cure, salt bulk and bulk salted fish).

round dan leno = dan leno hoop (a hoop-shaped dan leno made of bent wood with short rigging ropes wired to the outer circumference. Also called dan leno ring, geer, hoop, hoop bridle and yoke hoop).

round fish = fish in the "round" - not cleaned, without the head, the fins and guts removed.

round haul seine = a wall of seines arranged in an arc or semi-circle, the two ends being brought together and the bottom being at least partially closed to capture and concentrate the school, and the fish transferred on board a boat.

round salted fish = salt round fish (whole ungutted fish cured with salt. Also called round cure, bulk cure, kench cure, salt bulk and bulk salted fish).

round strap = one of a series of ring-shaped ropes encircling the codend or the strengthening bag of a trawl. Used to restrict stretching of the codend.

round-tail =a small cod gutted, headed and salted but not split.

round weight = the weight of the whole fish before processing or removal of any part. Same as fresh weight or live weight.

round-bend hook = a hook with a wide gape used for large baits.

rounder = 1) a demersal fish landed before being gutted; usually it is gutted at sea.

rounder = 2) dried and salted cod split insufficiently towards the tail (Newfoundland).

roundhauler = an endless trolling line (a slowly moving looped trolling line. The line is carried down to a specific depth, returned to the surface, passes over the vessel so that the catch can be removed and hooks re-baited, and then on down again).

rounding bias = a bias arising from the tendency of people to round off numbers to end in 0 or 5; important in angler surveys where catches are recorded from interviews. Also called digit bias.

roun = the role of a fish (archaic). Also spelled rowin, roune, ron and rone.

roune = roun.

rouny = consisting of roe (Scottish dialect).

rouse salt upon salt = to change the pickle in curing fish.

roused fish = fish mixed with dry salt before further handling and processing.

rousing tub = a container in which preliminary salting is carried out.

ROV = abbreviation for remotely operated vehicle.

rovack = the tail piece of a fish, especially a dried strip from the back of a dogfish, Squalus acanthias (Scottish dialect). Also spelled rovek and rovik.

rovek = rovack.

rovik = rovack.

row = fish teeth arranged in the mesial-distal direction across the jaw, e.g. in sharks. Such teeth are all at the same development stage. In a dentition with imbricated/pavement teeth, adjacent teeth in a row may have slightly different ages, cf. file, diagonal file and tooth row.

rowan cast = a part of a river where roe is favoured as a bait (Scottish dialect).

rowan gatherer = a name for the brown trout, Salmo trutta, because of its fondness for salmon roe.

rowboat = a boat propelled by oars.

rowin = roun.

royal Wulff dry fly = a series of fly patterns designed by Lee Wullf; bushy and high floating flies visible in rough water and at twilight.

rubber = false belly or chafing gear (any materials attached to wear points on nets). Attached below the belly of a trawl.

rubbish = any marine fish other than salmon and cod (Newfoundland).

rubble = stones of small or medium size, 76-305 mm diameter.

rubble = 1) irregular-shaped rock fragments of varying size.

rubble = 2) substrate particles in streams between 64 and 256 mm in diameter.

rubble zone = the shallowest part of a reef crest landward of the palmata zone. It consists of broken pieces of coral washed back by storms.

rubric = a section of a key; two rubrics form a couplet.

ructus = eructation (burping or belching is the release of gas from the digestive tract. In fishes this may be from the vent, or from the gas bladder connected to the gut via the pneumatic duct, and thence the mouth. Some eructations may be just emptying the gas bladder but others appear to be a deliberate sound production as it does not vary over time, e.g. in certain eels and catfishes).

rud = rod (3 and 4).

rude = rod (3 and 4).

rudimentary = very small and poorly formed; undeveloped; imperfectly developed.

rudimentary ray = a simple fin ray usually an unbranched, unsegmented soft ray, often too small or obscure to include in counts.

ruffie = a torch made from a brand of log fir or a wick of rag smeared with tallow and used for salmon fishing at night (Scottish dialect).

ruffy = ruffie.

rug = a pull or tug on a fishing line when a fish has been hooked; a bite (Scottish dialect).

ruga (plural rugae) = a ridge or fold, e.g. of the digestive tract that permits expansion and contraction.

rugae = plural of ruga.

rugg = rug.

ruggie = an undersized cod (Scottish dialect). Also spelled ruggy or rookie.

ruggy = ruggie.

rugose = wrinkled, corrugated, rough.

rugosity = a ridge or fold.

rule = in taxonomy, a mandatory Article of the International Code of Zoological Nomenclature.

ruling = a decision by the International Commission on Zoological Nomenclature published in an Opinion (q.v.), Declaration (q.v.) or Direction (a term no longer used in the code).

rumbal whitings = an old tradition at Folkestone where eight of the largest and best whitings were chosen out of every boat and sold separately. The money from this sale funded a Christmas feast, called a rumbal, for each boat crew. May originally have been an offering for St. Rumwold, to whom a chapel was dedicated near Folkestone.

run = 1) transitional segments of streams, between a riffle and a pool, with moderate to fast current and depth, little or no turbulence and a smooth water surface.

run = 2) seasonal migration undertaken by fish, usually as part of their life history.

run = 3) increased catches of fish, a usage often independent of their migratory behavior.

run = 4) the direction in which netting is braided.

run = 5) the regular movement of vessels between ports.

run = 6) the movement of a hooked fish trying to escape and the line pulled out in the process.

run = 7) a school of fish.

run = 8) a collective noun (a noun that denotes a collection of persons or things regarded as a unit) for fishes.

run = 9) a collective noun (a noun that denotes a collection of persons or things regarded as a unit) for salmon.

run = 10) a narrow strait or extended navigable passage between the coast and an island or islands.

run and gun = an angling method where only fish that strike quickly are caught, the angler fishing one area with a few casts and then "gunning" the boat motor to travel to the next area.

run clip = a plastic clip trapping the fishing line against the rod just above the reel. Used when legering. It releases when the fish runs with the bait.

run down = backwash (the seaward return of waves after they rush up onto the beach. Some fish species spawn in this wave action, e.g. capelin, Mallotus villosus. Also called backrush).

run-of-river = allowing flow of water through dam turbines at a constant speed, thus faciltating fish movements and migrations.

run-of-the-river dam = lowhead dam (a dam extending across a river of low height, usually 15 feet (about 5 metres) or less. It impounds the water behind it, has minimal effects on the downstream regime and allows water to fall over its whole width. Quite dangerous as boaters and swimmers may not see it until too late and can be caught in the backwash beneath the dam. Also called channel dam).

run reconstruction = a post-season assessment of all fish that escaped and all those that were harvested from individual stocks or management areas.

run-of-river impoundment = an impoundment having a high rate of flushing.

run-up = the rush of water up a structure such as a beach on the breaking of a wave. Also called uprush and swash.

runlet = a small stream.

runnel = a rivulet or brook, a narrow channel for water, a small stream.

runner = female sturgeon caught before the eggs are ripe.

running = 1) flowing as with water.

running = 2) current as with costs.

running lead = the British word for the North American term slip sinker (a lead or other metal weight having a hole through its centre, sliding freely up and down the fishing line).

running leger = a rig in angling where the line runs freely through the leger weight offering little resistance to the fish.

running line = a thin fly fishing line that connects at one end to a shooting head, q.v., and at the other to the backing on the reel.

running mark = a land feature lined up by a fisherman in order to locate the position of a fishing ground.

running paternoster = a paternoster rig (q.v.) where the weight is attached to a short link that runs freely on the line.

running ripe = ready to spawn as evidenced by a slight pressure on the abdomen causing eggs or milt to be shed.

running stick = a wooden device placed on the side of a dory and used as a guide for hauling trawls.

running water = any water body showing continuous unidirectional flow; water running from higher to lower elevations as in a river. Also called flowing water.

runoff = precipitation that flows across the ground and enters streams, rivers and lakes; may carry pollutants. Also used for the total discharge of a stream, both surface and subsurface, over a given time period. Defined as the depth to which a drainage area would be covered if all of the runoff for a given period of time were uniformly distributed over it.

runt = a stunted fish; one with less than usual growth for the species.

runting fish = runt.

russlet = kron-sardiner (1) small herring used as raw material for preserves, mostly in cans. The herring is eviscerated and headed and thoroughly washed (Sweden)).

russlet = kron-sardiner (2) small herring eviscerated, headed and vinegar cured for export (Norway)).

russlet = Kronsardinen ( marinated small herring or sprat, mostly from the Baltic Sea, sometimes with spices, sugar and other flavouring agents (Germany)).

rust disease = gold dust disease (an infectious disease caused by dinoflagellates evidenced by a golden or brownish dusty appearance on the fish skin through mucus production. The fish may show irritability, flashing, respiration difficulties and clamping of the fins. Very contagious and often fatal. Called velvet disease when Oodinium, coral fish disease when Amyloodinium and rust from the appearance).

rusting = yellowish or brownish discolouration often around the vent and belly and on cut surfaces causing a rancid flavour. Caused mainly by a reaction between fat oxidation products and nitrogenous substances when inadequately stored.

ryke = raik.

rynge = reenge.

© Brian W. Coad (www.briancoad.com)

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