Dictionary of Ichthyology

Brian W. Coad and Don E. McAllister^†

Revised: 15 November 2008

Abbreviations

The abbreviations given below can also be found in the letter files, placed as though each was a word.

A = acre (4046.9 m², 0.405 ha, 43,560 ft², 4840 yd², 0.00156 mi²).

A = anal fin (rays).

A = annual total mortality rate (the number of fish which die during a year divided by the initial number. Also called actual mortality rate, coefficient of mortality (Ricker, 1975)).

a or a = annum, meaning year. Usually used in combination, e.g. Ma, meaning million years.

a- (prefix) = lacking, absence of, not.

A-ft = acre-foot (one acre of surface covered with 1 foot of water (1,233,500 L, 1233.5 m³, 325,850 gal).

A1 = first anal fin (rays).

A2 = second anal fin (rays).

A30 = number of anal fin rays anterior to the 31st vertebra, e.g. in Carapidae.

A100 = number of anal fin rays anterior to the 201st vertebra, e.g. in Nemichthyidae.

ABC = allowable biological catch (a term used by a management agency which refers to the range of allowable catch for a species or species group. It is set each year by a scientific group created by the management agency and is the subjectively estimated amount of catch of a given species from a given region. The agency then takes the ABC estimate and sets the annual total allowable catch (TAC)).

ad. = adult.

AC = a series of ventro-lateral photophores extending between a vertical at the anal fin origin and the end on the caudal peduncle. The AC row may begin posterior to the anal fin origin if it is offset from other ventro-lateral photophores.

ac ft = acre-foot (one acre of surface covered with 1 foot of water (1,233,500 L, 1233.5 m³, 325,851 gal.). Used to measure volumes of water used or stored, such as in reservoirs).

A.D. or AD = anno domini, or Year of the Lord, the Christian dating system. Common era or CE is used as a neutral version.

ad int. = ad interim, meaning for the present, provisionally.

ADC= apparent digestibility coefficient (the value for the food absorbed from diet and not excreted in faeces; nutrient ingested - nutrient egested/nutrient ingested).

ADF = acid detergent fibre (the carbohydrates in an aquaculture feed that are not solubilised by acid detergent. This plant material is not easily used by fish).

adv. = advena, alien, introduced.

af = acre-foot (one acre of surface covered with 1 foot of water (1,233,500 L, 1233.5 m³, 325,851 gal.). Used to measure volumes of water used or stored, such as in reservoirs).

aff. = affinis (related to but not identical with, affinity, relationship, sometimes misleadingly employed as a synonym for phenetic similarity (or akin to)).

AFO = number of vertebrae anterior to the anal fin origin, e.g. in larval fishes.

al. = alii or aliorum, meaning others, of others.

AM, am or a.m. = ante meridiem or before noon; the time before 12 noon.

ami = air miles, the straight line distance between two points used when describing a specimen collection locality.

ANC = acid neutralising capacity (the property of water that reacts with an acid; formerly alkalinity).

Ant = a photophore at the anterodorsal margin of the orbit.

AO = a row of photophores along the base of the anal fin and lower side of the caudal peduncle (not including the Prc's at the base of the caudal fin) in Myctophidae. Usually divisible into AOa mostly above the anal fin base and AOp mostly on the caudal peduncle. In some older works AO refers to the antorbital photophores.

AOa = a row of photophores mostly above the anal fin base in Myctophidae.

AOp = a row of photophores mostly on the caudal peduncle in Myctophidae.

ap. = apud, meaning in the work of; used in citing the work of an author contained in another work.

Art. = an Article of the International Code of Zoological Nomenclature.

ascr. = ascriptum, meaning ascribed to.

ASPM = age-structured production model (a stock assessment programme based on a deterministic form of a stock-recruitment relationship, with non-equilibrium tuning of abundance indices).

auct. or auctt.= auctorum, meaning of authors. Used to indicate that a name is used in the sense of a number of subsequent authors and not in its different sense as established by the original author.

auct. non. = auctorum non, meaning not of authors, used when citing a misapplied name.

B = biomass (the weight, volume or energy of living material in a given area, sample, fraction such as spawners, stock or for one or more given species (species biomass) or of all the species in a biotic community (community biomass). In fisheries the weight of a fish stock or some defined part thereof (Ricker, 1975)).

B 20% B-virg = level of spawning stock corresponding to a fraction (here 20%) of the unexploited biomass. Virgin biomass is estimated as the point where the replacement line for F=0 intersects the stock-recruitment relationship or as the biomass from a spawning stock per recruit curve when F=0 and average recruitment is assumed.

B 50% R = the level of spawning stock at which average recruitment is one half (50%) of the maximum of the underlying stock-recruitment relationship.

B 90% R, 90% Surv = spawning stock corresponding to the intersection of the 90th percentile of observed survival rate (R/S) and the 90th percentile of the recruitment observations.

B₀ = virgin or unfished biomass (B zero). Rarely known. Using mathematical models, it is generally calculated as the long-term average biomass value expected in the absence of fishing mortality. In production models, B₀ is also known as carrying capacity. It is often used as a biological reference point in fisheries management.

BC, B.C. = before Christ. Used to designate years before the birth of Christ. Used in scientific dating for relatively recent events, e.g. fish remains in sub-fossil sites. Note there was no year 0.

BC = buoyancy compensator (buoyancy control device).

BCD = buoyancy control device (an expandable bladder in the form of an expandable vest used with scuba apparatus. It can be inflated with air from the scuba tank to increase buoyancy while diving and is used for resting, swimming or lending assistance to others under water. It is deflated by special air-dump valves or hoses. Also called a buoyancy compensator (BC)).

BCE = before the common era. Used to designate years before the birth of Christ in a non-Christian countries. Used in scientific dating for relatively recent events, e.g. fish remains in sub-fossil sites. Note there was no year 0.

B.P. = before present, conventionally before 1950 A.D. for dating.

bland FPC = bland fish protein concentrate (concentrate with lipids, odour and flavour removed under hygienic conditions (see fish protein concentrate)).

B_lim = limit biomass, the minimum level of spawning stock biomass. Below this level there is a higher risk that the stock will suffer a severe reduction in productivity. See also precautionary approach, F_pa, B_pa and F_lim.

Bloss = biomass at the lowest observed stock size.

B_MSY = biomass at MSY (the long-term average biomass value expected if fishing at F_MSY (the fishing mortality rate which, if applied constantly, would result in maximum sustainable yield. Can be estimated from simple biomass-aggregated production models or from age-structured models that include a stock-recruitment relationship)).

BOD = biological oxygen demand, q.v. BOD5 is the amount of dissolved oxygen consumed in five days.

B_pa = the precautionary spawning stock biomass, a higher level than B_lim (q.v.) to allow for uncertainties in assessment. See also precautionary approach, B_lim, F_pa and F_lim.

BR (or Br) = 1) photophores along the lower jaw of Myctophidae; formerly called maculae branchiostegae by some authors, or 2) branchiostegal rays.

B_threshold = minimum stock size threshold (the minimum size of the stock that is required to produce maximum sustainable yield, below which the stock would be considered overfished).

Bu = a photophore above the hind end of the upper jaw in Myctophidae. Formerly called macula buccae by some authors.

BWD = body weight daily (a measure of food requirement and/or uptake expressed as a percentage or as a decimal fraction).

C = 1) caudal fin (rays).

C = 2) Carboniferous, a period within the Paleozoic Era ca. 365-290 million years ago.

C = 3) the Roman numeral 100.

C = 4) Celsius, a measure of temperature on a metric scale used world-wide and by scientists. In North America and in older literature Fahrenheit is used. The conversion is ºF = (ºC x 9/5) + 32 and ºC = (ºF - 32) x 5/9. Usually presented as ºC or ºF but strictly 3ºC is an actual temperature while 3Cº is a range of three degrees.

c. = 1) cum, meaning with.

c. = 2) circa, meaning approximately, about.

c & s = cleared and stained ( a specimen with some tissues rendered transparent by various chemical treatments while others are stained to enhance their visibility. In fish osteological studies, the flesh is cleared with enzymes or potassium hydroxide and the bones stained red with alizarin red S and the cartilage blue with alcian blue).

C1 = principal caudal fin rays.

C2 = procurrent caudal fin rays.

C/E = catch per unit effort (an older term for the catch in numbers or weight taken for a given amount of fishing effort over time using specific gear, expressed as a ratio. Often considered an index of fish biomass or abundance. May be used as a measure of economic efficiency of fishing. Also called fishing success, availability, catch per effort. Also abbreviated as CPUE. The more recent form is catch/effort (C/f or Y/f) where C is catch in numbers, Y is catch in weight, taken by a defined unit of fishing effort, f).

CAGEAN = catch-at-age-analysis; the estimated number of fish caught, tabulated by fish age and year of capture, and by other factors such as gear or nation. Catch-at-age may be estimated on the basis of catch-at-size, using age-length keys or cohort slicing.

CE = common era, a non-religious way of expressing years in the calendar based on the years of the Christian era. Note there is no year 0 so the year before 1 CE (or 1 A.D.) is 1BCE (or 1 B.C.).

C_E = equilibrium catch (the catch (in numbers) taken from a fish stock when it is in equilibrium with fishing of a given intensity, and (apart from the effects of environmental variation) its abundance does not change from one year to the next (Ricker, 1975). Also called sustainable yield, equilibrium yield).

Ce = photophore at the upper end of the gill cover where it meets the lateral line in Myctophidae. Formerly called maculae cervicis.

ca. = circa, meaning approximately, about.

cf., cfr. = confer, meaning compare (with). Used with scientific names to indicate a similarity to the named species without certain identification; a provisional identification due to a damaged specimen or other problems.

cfs-day = the volume of water represented by a flow of 1 cubic foot per second for 24 hours (equals 86,400 cubic feet, 1.983471 acre-feet or 646,317 gallons).

cfsm (cubic feet per second per square mile) = the average number of cubic feet of water per second flowing from each square mile of area drained by a stream, assuming that the runoff is distributed uniformly in time and area.

CHV = cyprinid herpesvirus I (one of the oldest known fish diseases found in cultured carp, other cyprinids, pike-perch and aquarium fishes. It is caused by Herpesvirus cyprini. Also known as carp pox, carp papillomatosis, epithelioma papulosum, and fish pox.. Skin lesions appear as the water temperature drops in winter as small milky-white spots that merge and cover large skin areas).

CITES = the Convention on International Trade in Endangered and Threatened Species. Regulates trade in live and dead animals and plants in an effort to conserve those species in danger of extinction.

Cl = chlorinity, the total amount in grams of chlorine, bromine, and iodine contained in one kilogramme of seawater, assuming the bromine and iodine to be replaced by chlorine. Salinity in parts per thousand (‰) = 1.80655 x Cl (‰).

cm^{3 =} cubic centimetre (0.0338 fl oz, 0.00211 pt, 1.0 mL).

CNS = central nervous system, the brain and spinal chord.

coll. = collector (a person or institution who finds and secures specimens). Abbreviation often occurs on labels and is scientific descriptions of species.

comb. nov. = combinatio nova, meaning new combination.

comb. rev. = combinatio revivisco, meaning combination revived when a combination is reinstated, e.g. from an earlier synonymy.

comm. = communicavit, meaning (s)he communicated.

cons. = conservandum, meaning to be conserved.

COR = coronal pore.

corr. = correctus, meaning corrected (by).

CPR = catch, photograph, release, a management tool for preserving angling stocks.

CPUE = catch per unit effort (an older term for the catch in numbers or weight taken for a given amount of fishing effort over time using specific gear, expressed as a ratio. Often considered an index of fish biomass or abundance. May be used as a measure of economic efficiency of fishing. Also called fishing success, availability, catch per effort. Also abbreviated as C/E. The more recent form is catch/effort (C/f or Y/f) where C is catch in numbers, Y is catch in weight, taken by a defined unit of fishing effort, f).

CPY = current potential yield (the catch that can be taken given the current resource abundance and prevailing ecosystem considerations).

CR = critically endangered (in the IUCN Criteria for threatened species, a taxon is Critically Endangered when it is facing an extremely high risk of extinction in the wild in the immediate future).

ctmax = critical thermal maximum (in fish exposed to a constant rate of heating, the temperature at which there is a loss of equilibrium or onset of muscle spasm).

ctmin = critical thermal minimum (in fish exposed to a constant rate of cooling, the temperature at which there is a loss of equilibrium or onset of muscle spasm).

cusec = cubic foot per second. Used outside North America where the equivalent is cfs.

CWT = coded-wire tag (a small (0.25 mm diameter x 1 mm length) wire etched with a distinctive binary code and implanted in the snout of a fish (usually a salmonid) for mark-recapture studies).

cwt = hundredweight (50.802 kg (long), 45.359 kg (short)). Abbreviated as cwt, long and cwt, short respectively.

CyHV-1 = cyprinid herpesvirus I or carp pox (one of the oldest known fish diseases found in cultured carp, other cyprinids, pike-perch and aquarium fishes. It is caused by Herpesvirus cyprini. Also known as carp papillomatosis, epithelioma papulosum, and fish pox. Skin lesions appear as the water temperature drops in winter as small milky-white spots that merge and cover large skin areas).

CyHV-2 = cyprinid herpesvirus II, a haematopoietic necrosis herpesvirus which affects goldfish and is closely related to carp pox or CyHV-1 and koi herpes virus or CyHV-3. A member of the family Herpesviridae as above.

CyHV-3 = cyprinid herpesvirus III, also known as koi herpes virus (KHV). This is a deadly virus affecting carp including koi. A member of the family Herpesviridae as above. There is no cure for the disease and it is difficult to detect.

D = 1) dorsal fin (rays).

D = 2) Devonian, a geological period within the Palaeozoic Era ca. 413-365 million years ago; called the Age of Fishes.

Dº = day-degree (a unit taking temperature and time in days into consideration to indicate degree of development. Calculated by adding the average daily temperature for each day, e.g. if the average daily temperatures that a 3-day-old trout egg has been subjected to are 11, 12 and 13 degrees centigrade, the eggs are at the 36 day degree stage. This is abbreviated 36 D).

D1 = first dorsal fin (rays).

D2 = second dorsal fin (rays).

D3 = third dorsal fin (rays).

D30 = number of dorsal fin rays to the 31st vertebra, e.g. in Carapidae.

D200 = number of dorsal fin rays to the 201st vertebra, e.g. in Nemichthyidae.

DD = data deficient (in the IUCN Criteria for threatened species, a taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution is lacking. Data Deficient is therefore not a category of threat or Lower Risk. Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate. It is important to make positive use of whatever data are available. In many cases great care should be exercised in choosing between DD and threatened status. If the range of a taxon is suspected to be relatively circumscribed, if a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified).

descr. = descriptione, meaning description.

det. = determinavit, meaning (s)he identified or determined. Often used for identification notes in collections. Also the abbreviation for determiner.

DFO = number of vertebrae anterior to the dorsal fin origin, e.g. in larval fishes.

dGH = degrees of water hardness (water hardness expressed in degrees of hardness. 0-4 is very soft, 5-8 soft, up to 30 which is extremely hard water). Also a degree of water hardness in Britain and the U.S.A. is measured in Clark degrees which equal 14.3 p.p.m. (1 part of calcium carbonate per 70,000 parts of water or 17.1 mg/L). In France 10 p.p.m. is used and in Germany 17.8 p.p.m.).

DH (dh or dH) = hardness, expressed in degrees (Germany). 1 DH = 17.86 p.p.m. Also used, confusingly, for water hardness generally as there are English, American and French measures too (see degrees of water hardness).

DHA = docosahexaenoic acid (an omega-3 fatty acid found in fish which protects ageing rodent brains from the clumping seen in Alzheimer's disease. May account for the reduction in risk of dementia and stroke in humans as a diet of fish replaces DHA lost in ageing).

DLS = double-layered spiral (a material made by rolling up a polyester pad and plastic wire mesh. It is used in both biological and mechanical filters in aquaria).

DMSP = dimethylsulphoniopropionate (a chemical released by phytoplankton and benthic algae, associated with coral reefs, when eaten. Planktivorous reef fishes use this chemical as a foraging clue).

Dn = a photophore in front of and above the eye and the olfactory capsule of Myctophidae.

DO = dissolved oxygen (the amount of oxygen freely available in water and necessary for aquatic life and the oxidation of organic materials. For fish, ideal levels are about 7-9 mg/l and most fish cannot survive levels below 3 mg/l).

DS = dissolved solids (very small pieces of organic and inorganic material contained in water. Excessive amounts make water less habitable for fish, unfit to drink or limit its use in industrial processes).

DSL = deep scattering layer (a layer in mid-depths of the sea detected by echo sounders, which rises at night and sinks during the day. Composed of organisms, many of which have a gas filled chamber, such as certain jellyfish and fishes. Also called false bottom).

DWT = dressed or dressing weight, the weight of a dressed fish (a fish with viscera, head and tail removed (some fish may have the tail on) but with skin and bone retained).

dz = doppel zentner (100 kg).

E = 1) exploitation rate (the proportion of a population at the beginning of a given time period that is caught during that time period (usually on a yearly basis). Also the ratio of fish caught to total mortality (= F/Z when fishing and natural mortality take place concurrently (Ricker, 1975)). Also called rate of exploitation).

E = 2) electivity index (an index showing the degree of choice a predator shows in its feeding behaviour, e.g. of a predator on plankton; E is derived from r_i - p_i / r_i + p_i where r_i is percent composition of plankter i in the gut contents and p_i is percent composition of plankter i in the plankton sample. Values for E range from -1 to +1 with -1 meaning complete avoidance, 0 meaning no active selection, and +1 meaning complete selection).

e.g. = exampli gratia, meaning for example.

e.p. = ex parte, meaning in part, partly.

EA = enterprise allocation (a quota from a particular fishery stock allocated to one company operating more than one vessel. Must be fished during the year allocated although timing is up to the company and the allocation can be transferred to another company).

EC = effective concentration (the concentration of a substance in water needed to produce a specific effect to a portion of test animals, e.g. EC₅₀ is the concentration producing an effect in 50% of the test fish).

EEZ = Exclusive Economic Zone (waters out to 200 nautical miles (370.40 km) from shore where international waters begin. Reserved to that country for exploitation and management of resources. Also called the 200-mile limit).

EFL = eye-fork length (straight or curved-body length between the posterior orbit and the fork of the tail; used in measuring billfish species).

EFZ = Exclusive Fishing Zone (the exclusive fishing zone out to 200 nautical miles, replaced by the EEZ).

EIS = Environmental Impact Statement.

emend. = emendatus, emended or altered (by); used where the author has changed the original spelling of a taxon without excluding the type of the name. The abbreviation precedes the name of the author effecting the change.

EN = endangered (said of a species facing imminent extirpation (nationally) or extinction (world-wide), in the IUCN Criteria for threatened species, a taxon is Endangered when it is not Critically Endangered but is facing a very high risk of extinction in the wild in the near future).

EPA = eicosapantaenoic acid, an omega-3-fatty acid, q.v., found in fish oil; its chemical name is all-cis-5,8,11,14,17-icosapentaenoic acid. Also called icosapentaenoic acid and timnodonic acid.

ERM = enteric redmouth disease (a systemic bacterial disease caused by Yersinia ruckeri found mostly in salmonids. Symptoms are severe congestion, septicaemia and haemorrhage in head tissues such as the palate and operculum with the lower jaw being eroded. Internal organs can also be infected. Abbreviated as ERM. Also called Hagerman redmouth disease).

err. typogr. = errore typographico, meaning typographical error.

ESU = evolutionarily significant unit (a population or group of populations inhabiting a defined geographical area that comprises a unique segment of the species; a distinct population, reproductively isolated from other conspecific populations and is an important evolutionary legacy of the species).

et al. = et alii meaning and others; used in author citations where the initial author's name is followed by et al. to indicate there are more authors.

etc. = et cetera, and so on.

EW = extinct in the wild ( in the IUCN Criteria for threatened species, a taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalised population (or populations) well outside the past range. A taxon is presumed extinct in the wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form).

EX = extinct (in the IUCN Criteria for threatened species, a taxon is Extinct when there is no reasonable doubt that the last individual has died).

ex aff. = ex affinis, meaning of affinity.

ex gr. = ex grupo, meaning of the group of.

excl. = exclusus, meaning excluded. Used to indicate those components included in a given taxon by one author but excluded by the present author.

excl. gen. = excluso genere, meaning with the genus excluded.

excl. spec. = exclusa speciei, meaning with the species excluded.

excl. specim. = exclusis speciminibus, meaning with the specimens excluded.

Extra E = the highest grade of freshness in the European community.

EW = extinct in the wild (in the IUCN Criteria for threatened species, a taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalised population (or populations) well outside the past range. A taxon is presumed extinct in the wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form).

F = 1) the fishing mortality rate in a particular stock. It is roughly the proportion of the fishable stock that is caught in a year.

F = 2) Fahrenheit, a measure of temperature used in the U.S.A. and in older literature. The conversion is ºF = (ºC x 9/5) + 32 and ºC = (ºF - 32) x 5/9. Usually presented as ºF (or ºC) but strictly 3ºF is an actual temperature while 3Fº is a range of three degrees. Water freezes at 32°F and boils at 212°F.

F = instantaneous rate of fishing mortality (used to describe 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). Also called rate of fishing; instantaneous rate of fishing mortality, force of fishing mortality).

f (or f) = fishing effort (effective fishing effort (Ricker, 1975), e.g. hooks per day, adjusted or standardised, when necessary, so that each increase in the adjusted unit causes a proportional increase in instantaneous rate of fishing (Ricker, 1975). Controls purported to limit effective effort imply that the fishing mortality rate is to be limited. Also abbreviated as F/q or F/q).

f. = forma or form (i.e. a neutral term for a single individual, phenon, or taxon; a group; or an infrasubspecific group, or in the past, a subspecies (not recommended usage)). According to the International Code of Zoological Nomenclature the use of the term "form" before 1961 is not to be interpreted as an express statement of either subspecific or infrasubspecific rank and after 1960 it is to be regarded as of infrasubspecific rank). Also used as an abbreviation for figura, meaning figure or illustration.

(f) = female.

F0.1 or F _0.1 (F zero point one) = the fishing mortality rate at which the marginal yield-per-recruit, i.e. the increase in yield-per-recruit in weight for an increase in one unit of fishing mortality, is only 10 percent of the marginal yield-per-recruit on the unexploited stock. The fishing mortality rate at which the slope of the yield-per-recruit curve is only one-tenth the slope of the curve at its origin. It is an approximation to the level of fishing mortality that will generate the maximum sustainable yield when a more accurate estimate is not possible.

F₁ = the offspring resulting from a parent cross, the first generation (F₂ is the second generation).

F10% = the level of fishing mortality, F, at which an average female in the population will produce 10% of the eggs that would be produced by a female that was left to live out her natural life span, i.e. unfished.

F30%SPR = F corresponding to a spawning stock biomass per recruit (SSB/R) which is 30% of the SSB/R obtained when F=O.

F/O = fish only, a saltwater aquarium that only contains fish with non-living rocks, corals, shells, and other decorative items. Abbreviated also FO.

F/q or F/q = effective fishing effort (fishing effort, e.g. hooks per day, adjusted or standardised, when necessary, so that each increase in the adjusted unit causes a proportional increase in instantaneous rate of fishing (Ricker, 1975). Controls purported to limit effective effort imply that the fishing mortality rate is to be limited).

F-ratio = the ratio of fishing mortality on the oldest age group to the fishing mortality of the preceding age group. Annual F-ratios are estimable parameters in many tuned virtual population analysis assessments.

FAD = 1) fish aggregating device (artificial or natural floating objects placed on the ocean surface, often anchored to the bottom or drifting, to attract several schooling fish species underneath, thus increasing their catchability. Used with tuna, for example. Also called fish attracting device).

FAD = 2) fish attracting device; variant on FAD (1).

fath = fathom (a measure of water depth, 1.8288 metres, 6 feet or 2 yards).

FCZ = Fishery Conservation Zone (the area from the seaward limit of state waters out to 200 nautical miles. The term is used less often than the current term, Exclusive Economic Zone).

fh = a French measure of water hardness, 10.0 p.p.m. calcium carbonate.

FL = fork length (the distance from the most anterior point of the body to the deepest point of the fork in the caudal fin. Mostly used in fishery biology and not in systematics).

fl oz = fluid ounce (29.573 g water).

fl oz_BI = Imperial fluid ounce (28.413 millilitres or cm³).

fl. = floriat, flourished, referring to the period of greatest success and diversity of a taxon.

F_lim = limit fishing mortality, a value above which fishing should be avoided. See also precautionary approach, F_pa, B_pa and B_lim.

Floss or F_loss = fishing mortality corresponding to an expected lifetime contribution to the spawning stock biomass for the average recruit to the fishery (SSB/R) equal to the inverse of R/SSB at the lowest observed spawning stock (LOSS).

Flow or F_low = fishing mortality (F) corresponding to a SSB/R equal to the inverse of the 10% percentile of the observed R/SSB.

Fmax or F_max = the rate of fishing mortality for a given exploitation pattern, rate of growth, and natural mortality that results in the maximum yield per recruit; the point that defines growth overfishing.

Fmed = the fishing mortality rate corresponding to an equilibrium spawning potential ratio (SPR) equal to the inverse of the median observed survival ratio (ratio of recruits to parental spawning biomass). Such a stock exploited at Fmed should be able to replace itself close to historical abundance.

FMP = Fishery Management Plan (a plan to achieve specified management goals for a fishery. It includes data, analyses, and management measures for a fishery).

FMSY or F_MSY = the fishing mortality rate which, if applied constantly, would result in maximum sustainable yield. Can be estimated from simple biomass-aggregated production models or from age-structured models that include a stock-recruitment relationship.

FO = fish only, a saltwater aquarium that only contains fish with non-living rocks, corals, shells, and other decorative items. Abbreviated also F/O.

fopt = the effective fishing effort corresponding to FMSY (q.v.). Also called fMSY.

F_pa = the precautionary fishing mortality, a lower level than F_lim (q.v.) to allow for uncertainties in assessment. See also precautionary approach, B_lim, B_pa and F_lim.

FPC = fish protein concentrate (a flour comprised of dried and powdered fish used as a food supplement. It is odourless, tasteless and has more protein than in the original fish flesh).

FRT = fast repetitive tick = a high-pitched sound caused by a stream of air bubbles expelled from the anus of herring (Clupea pallasii). Apparently used in communication (http://www.newscientist.com/news/news.jsp?id=ns99994343, downloaded 29 November 2003).

ft = foot (0.305 m, 12 inches).

ft/min = feet per minute (0.5080 cm/s, 0.0167 ft/s).

ft/s = feet per second (30.48 cm/s).

ft³ = cubic foot (957.5 fl oz, 59.84 pt, 28.317 mL, 0.0283 m³⁾.

ft³/s = cubic feet per second (28.317 L/s, 7.841 gal/sec).

F_threshold = maximum fishing mortality threshold (the rate of fishing mortality, that if exceeded, will result in overfishing and jeopardize the capacity of a stock to produce maximum sustainable yield on a continuing basis).

FX% = the fishing mortality that will reduce the equilibrium spawning potential per recruit to X% of what it would be without any fishing. It is also the F that results in X% equilibrium spawning potential ratio. Also called FX%SPR.

G (or g) = instantaneous rate of growth (a measure of the weight increase, the natural logarithm of the ratio of final weight to initial weight of a fish in a unit of time, usually a year. When applied collectively to all fish of a given age in a stock, the possibility of selective mortality must be considered (Ricker, 1975). The formula is g = [Ln(Wt) - Ln(W0)]/(t1-t0) where Wt is the weight of the fish after t1 days and W0 is the initial weight).

g = gram(me) (0.0022 lb).

G.S.I. = gastrosomatic index (weight of gut in grammes x 100/weight of fish in grammes (Desai, 1970)).

gal = gallon (U.S., 3.785 L).

gal_BI = gallon (Imperial, 4.454 L).

gal/min = gallon per minute (3.875 L/min).

gen. = genus, meaning genus

gen. et sp. nov. = genus et species nova, meaning new genus and speceis.

gen. nov. = genus novum, meaning new genus.

gen. rev. = genus revivisco, meaning genus revived for a reinstated genus from an earlier synonymy.

GH = general, total or permanent hardness. A measure of the overall concentration of calcium, magnesium and other ions. One degree equals about 17.9mg/l. The degree symbol is often replaced with a "d" (i.e. 6dGH). The harder the water, the higher the GH.

GIS = Geographic Information System (a computer system based on geographical coordinates (latitude and longitude) linked to various data such as temperature, habitat type, depth, catches, etc. used in zoogeographical analyses).

Gloss = the replacement line corresponding to the lowest observed spawning stock (or loss). The slope of the replacement line joining the origin of the stock-recruitment plot to the point given by the fitted recruitment value Rloss, at the lowest observed spawning stock biomass, Sloss. The slope is calculated from Gloss = Rloss/Sloss.

GPS = global positioning system (a hand-held electronic system that uses satellite signals to give exact locations on the earth's surface as latitude and longitude. Variously used for locating fisheries, favourite angling spots and scientific sampling locations. Takes all the fun out of getting lost with maps).

GSI = gonosomatic index (gonad weight expressed as a percentage of whole body weight).

h (or h) = annual growth rate (the increase in weight of a fish over one year (final weight divided by initial weight) (Ricker, 1975).

h and g = headed and gutted. Factory ships often remove the head and guts of fish before freezing them.

ha = hectare (107,640 ft², 10,000 m²).

HNV = high nutritional value (a term used to describe baits in angling, especially boilies).

HSL = hepatosomatic index ( liver weight as a percentage of the whole body weight (Htun-Han, 1978)).

i.e. = id est or that is.

IBI = index of biotic integrity (the use of fish sampling data to indicate the overall health and integrity of a stream. Measures of fish species composition, trophic composition, reproductive behaviour and abundance and condition are used. Sites with high biotic integrity have relatively high numbers of total species).

ib. = ibidem, meaning in the same place; used to indicate same reference or author.

ibid. = ibidem, meaning in the same place; used to indicate same reference or author.

IC = the entire, ventral row of photophores running from the anterior end of the isthmus to the posteriormost photophore on the caudal peduncle.

ich = ichthyology.

ICZN = International Commission on Zoological Nomenclature, the judicial body empowered to enforce and interpret the International Code of Zoological Nomenclature (which presumably has the same acronym).

iex = ion exchange (a process used in aquaria to treat the water, softening it or removing pollutants).

IFQ = individual fishing quota (a quota, e.g. a percentage, of a total allowable catch assigned to an individual, a vessel or a company. Also called individual quota).

IGFA = the International Game Fish Association which records and maintains capture data on angled fishes.

IHN = infectious haematopoietic necrosis (an acute Rhabdovirus-group viral disease of salmonids transmitted from fish to fish and by eggs in western North America, e.g. in chinook and sockeye salmon and rainbow trout. The disease destroys the haemotopoietic tissues in the kidneys. Particularly affects fish less than 5 cm long in water below 10°C. Potentially dangerous to humans).

in. = inch (2.54 cm).

in adnot. = in adnotatione, meaning in an annotation.

in litt. = in litteris (in correspondence or communicated in writing. Used for an unpublished source of information. NOT in literature).

in syn. = in synonymis, meaning in synonymy.

inc. sed. = incertae sedis (of uncertain seat, meaning of uncertain taxonomic position or affinities).

incl. = inclusus, meaning included.

INM = an international nautical mile (1.852 kilometres, 1.151 miles or 1 minute latitude of the great circle of the earth. Three nautical miles make one league. The British nautical or Admiralty mile was 6080 feet (1853.18 m) while the U.S. nautical mile was 6080.2 feet (1853.24 m)).

IO = infraorbital canal (the cephalic lateral line canal (q.v.) extending from behind and below the eye to behind the upper lip).

IP = initial phase in diandric fishes (possessing two different types of males, a large, brightly-coloured and aggressive terminal phase (TP) and a smaller, drab and relatively non-aggressive initial phase (IP), e.g. in Thalassoma lunare (Labridae). The TP has priority access to food and spawning females. On the death or removal of a TP, the first-ranking IP becomes the next TP (after first checking the reef thoroughly to make sure the TP is gone)).

IQ = individual quota (a quota, e.g. a percentage, of a total allowable catch assigned to an individual, a vessel or a company. Also called individual fishing quota).

iqf = individually quick frozen.

ISA = infectious salmon anaemia (a viral disease of salmonids such as Atlantic salmon, sea-run brown trout and rainbow trout. The anaemia leaves fish open to other diseases and the kidneys may haemorrhage and the spleen swell. The disease is transmitted from fish to fish and from sea lice to fish).

ITQ = individual transferable quota (assigning a fixed share of the catch to each fisherman as a tradable right, one that can be sold or leased to others).

IUCN = International Union for Conservation of Nature and Natural Resources.

IUCN Criteria = criteria developed to assess the threatened status of species using numerical measures of populations, their levels, range, decline, etc.

IUU = illegal, unregulated and unreported fishing vessels.

IV = a row of ventral photophores running from the anterior end of the isthmus to the origin of the pelvic fin.

J = Jurassic, a geological period of the Mesozoic Era ca. 210-140 million years ago.

K = Cretaceous, a geological period of the Mesozoic Era ca. 140-65 million years ago.

ka = thousands of years ago.

kaf = 1000 acre-feet. Used in reservoir management in the U.S.A.

kg = kilogram(me) (2.2046 lb).

KH = buffering capacity, temporary or carbonate hardness, measured in degrees (K is from the German word karbonate). KH makes up a component of GH, q.v., so boiling will also reduce GH slightly. One degree KH is equal to 17.9 mg/l CaCO₃. The degree symbol may be replaced with a d e.g. 2 dKH).

KHV = koi herpes virus (a viral infection of both ornamental koi and fish-farmed common carp (Cyprinus carpio) and therefore of considerable effect on economically valuable populations. First isolated in 1998, there is no test for it during the asymptomatic period which can be lengthy).

km = kilometre (0.621 mi).

kn = knot (speed in nautical miles per hour, 1.0 INM/h, 1.15 m.p.h. or 1.8532 km/h).

ky = 1000 years.

L = litre (33.81 fl oz, 0.264 gal).

L₁ = total length at formation of first winter annulus in the scale or otolith.

l₁ = total length at formation of first winter annulus in the scale or otolith as determined by back calculation from the formula l₁ = Lv/V where v is the linear dimension of the scale within the first winter annulus and V is the linear dimension of the scale.

L₅₀ = length at first maturity (length at which 50% of the individuals of a given sex are considered to be reproductively mature. Usually based on females and estimated by fitting a logistic curve to the relationships between proportion mature and length).

L/min = litres per minute (0.264 gal/min).

lat. = latus, meaning wide or broad.

lb = avoirdupois pound (0.454 kg).

lb tr = troy pound (0.373 kg).

LD₅₀ = lethal dose–50 or the dose of a toxicant that is fatal to 50 percent of the fish tested over a specified time.

leg. = collector from the Latin lego to gather, collect and legulus, a collector. A person or institution who finds and secures specimens. Abbreviation often occurs on labels and is scientific descriptions of species. See also coll.

loc. cit. = loco citato, place cited (publication and page), meaning cited above; used to avoid repetition of a reference.

LR = lower risk (in the IUCN Criteria for threatened species, a taxon is Lower Risk when it has been evaluated, does not satisfy the criteria for any of the categories Critically Endangered, Endangered or Vulnerable. Taxa included in the Lower Risk category can be separated into three subcategories: 1) Conservation Dependent (cd). Taxa which are the focus of a continuing taxon-specific or habitat-specific conservation programme targeted towards the taxon in question, the cessation of which would result in the taxon qualifying for one of the threatened categories above within a period of five years, 2) Near Threatened (nt). Taxa which do not qualify for Conservation Dependent, but which are close to qualifying for Vulnerable and 3) Least Concern (lc). Taxa which do not qualify for Conservation Dependent or Near Threatened).

LRP = limit reference point (indicates the limit beyond which the state of a fishery and/or a resource is not considered desirable. Fishery development should be stopped before reaching it).

LTPY = long-term potential yield (the largest average harvest that can be taken from a fish stock on a sustainable basis, allowing for variable environmental conditions).

M = instantaneous rate of natural mortality (when natural and fishing mortality operate concurrently it is equal to the instantaneous total mortality rate, multiplied by the ratio of natural deaths to all deaths (Ricker, 1975). Also called force of natural mortality).

m = annual mortality rate (the ratio between the number of fish which die during a year from causes other than fishing and the number alive at the beginning of that year. Also called annual natural mortality rate, conditional natural mortality rate, seasonal natural mortality rate). Also abbreviated as n.

m (or m) = conditional fishing mortality rate (the fraction of an initial stock which would be caught during the year (or season) if no other causes of mortality operated (Ricker, 1975). Also called annual or seasonal fishing mortality rate).

m = metre (1.094 yd).

m. = muscle.

m. = musculus.

m. = mihi, meaning to me, of me, used to show the writer's responsibility for a statement or proposal.

(m) = male.

m.s.l. = mean sea level.

Ma = million years ago.

maf or Maf = million acre-feet.

masc. = masculus, meaning male.

max = maximum.

MCS = monitoring, control and surveillance (activities by the fisheries enforcement system to ensure compliance with fishery regulations).

MEC = maximum equilibrium catch (maximum sustainable yield (the average or maximum catch that can be removed under existing environmental conditions over an indefinite period without causing the stock to be depleted, assuming that removals and natural mortality are balanced by stable recruitment and growth. Also called maximum equilibrium catch, maximum sustained yield, sustainable catch).

MEI = morphoedaphic index (an index of potential fish production in lakes. Calculated by total dissolved solids (mg/l)/mean depth in metres).

MEY = maximum economic yield (the total amount of profit that could be earned from a fishery if it were owned by an individual).

mho = abbreviation for conductivity, q.v., measured in micromhos (siemens is the metric version).

mi = mile (1.609 km, 0.870 INM).

min. parte = pro minore parte, meaning for the smaller part.

mm = millimetre.

mm. = muscles.

MS (MSS plural) = manuscript (a text, either handwritten or typed, but not available in multiple copies. Used for the copy of a scientific paper submitted to a journal for publication).

MS-222 = tricaine methanesulphonate, a fish anaesthetic applied by immersion in dosed water.

MSDS = Material Safety Data Sheet (documents form the manufacturer of a chemical outlining its toxicity, volatility, flammability and other safety related information. Posted in laboratories where such chemicals are used; formalin is probably the commonest and most toxic chemical encountered by ichthyologists).

MSP = maximum spawning potential of a fish stock (spawning potential ratio, q.v., or % MSP (the ratio of spawning potential per recruit under a given fishing regime relative to the spawning potential per recruit with no fishing)).

MSST = B_Threshold or minimum stock size threshold or MSST. At stock sizes below B_Threshold, the stock is considered to be overfished.

MSY = maximum sustainable yield (the average or maximum catch that can be removed under existing environmental conditions over an indefinite period without causing the stock to be depleted, assuming that removals and natural mortality are balanced by stable recruitment and growth. Also called maximum equilibrium catch, maximum sustained yield, sustainable catch).

MT = metric ton (tonne; 1000 kilogrammes, 0.984 long tons, 1.1023 short tons or 2204.6 pounds).

mt = metric ton (tonne; 1000 kilogrammes, 0.984 long tons, 1.1023 short tons or 2204.6 pounds).

mtDNA = mitochondrial DNA (a form of DNA, the chemical basis of heredity, found in the mitochondria (or energy producing structures within cells) and used to identify and relate fish species).

mut. char. = mutatis characteribus (with the characters changed (by); emend., emendatus).

my = million years (ago).

MYA = million years ago.

mybp = million years before present.

myr = million years (ago).

N = number of fish studied; n is often used.

n = annual mortality rate (the ratio between the number of fish which die during a year from causes other than fishing and the number alive at the beginning of that year. Also called annual natural mortality rate, conditional natural mortality rate, seasonal natural mortality rate). Also abbreviated as m.

n = the haploid chromosome number.

n. = nobis, meaning to or of us; nomen, meaning name; novus, meaning new; nudum, meaning naked.

n.b. = nota bene, take notice, note well. Also NB.

n. g. = new genus.

n. n. = nomen novum, q.v., or new name; or nomen nudum, q.v.

n. nov. = nomen novum, q.v., or new name.

n. sp. = nova species, meaning new species.

n. v. = non visus, meaning not seen.

NAFO = Northwest Atlantic Fisheries Organization, responsible for setting quotas for some stocks that are outside Canada’s 200-mile limit, straddle the line, or are of mainly foreign interest.

NB = nota bene, take notice, note well. Also n.b.

nei = not elsewhere included. In fisheries catch statistics, refers to catch data that cannot be linked directly to a State or fishing entity, for whatever reason.

NL = notochord length (the distance from the snout tip to the posterior tip of the notochord).

no. = numero, meaning number.

nob. = nobis (to or of us; used after a scientific name to indicate the author's responsibility for its description, or for an action or proposal).

nom. = nomen, meaning name.

nom. abort. = nomen abortivum (a name contrary to the International Code of Zoological Nomenclature as the Code existed at the time of publication).

nom. ambig. = nomen ambiguum (an ambiguous name, one used by different authors for different taxa over so long a period that is has become a persistent cause of error and confusion).

nom. conf. = nomen confusum (confused name a name based on elements of more than one species from which it is impossible to select a lectotype).

nom. confus. = nomen confusum (confused name a name based on elements of more than one species from which it is impossible to select a lectotype).

nom. cons. = nomen conservandum (a name preserved by the International Commission on Zoological Nomenclature and entered on their Official Lists even though it strictly contravenes one or more provisions of the Code).

nom. conserv. = nomen conservandum (a name preserved by the International Commission on Zoological Nomenclature and entered on their Official Lists even though it strictly contravenes one or more provisions of the Code).

nom. dub. = nomen dubium (a doubtful or dubious name not certainly applicable to any known taxon; a name which cannot be recognized because of inadequate description, figure, etc. May possess availability conducive to uncertainty and instability).

nom. hybr. = nomen hybridum (hybrid name, formed by combining words from different languages).

nom. illeg. = nomen illegitimum (illegitimate name, a validly published name that must be rejected for the purposes of priority in accordance with the International Code of Zoological Nomenclature).

nom. illegit. = nomen illegitimum (illegitimate name, a validly published name that must be rejected for the purposes of priority in accordance with the International Code of Zoological Nomenclature).

nom. inq. = nomen inquirendum (a name which should be investigated).

nom. inval. = nomen invalidum (invalid name, a name that is not validly published or is unavailable).

nom. legit. = nomen legitimatum (legitimate name, a valid name published in accordance with the provisions of the International Code of Zoological Nomenclature).

nom. monstr. = nomen monstrositatum (a scientific name based on a monstrosity (a physically abnormal specimen)).

nom. non rite public. = nomen non rite publicatum (not properly published name, used to indicate that a name has not been validly published according to the provisions of the International Code of Zoological Nomenclature).

nom. nov. = nomen novum (a new name which is published to replace an earlier name (and valid only if the latter is preoccupied) and which is expressly proposed as a replacement name; a new name, not to be confused with a new species, or a new genus, etc., which represent new taxa. Commonly applied to names proposed to replace junior homonyms).

nom. nud. = nomen nudum (a naked name, a name that, if published before 1931, was not accompanied by a description, definition, or indication, or if published after 1930, is not accompanied by a statement that purports to give characters differentiating the taxon; or is not accompanied by a definite bibliographic reference to such a statement; or is not proposed expressly as a replacement for a pre-existing available name. A nomen nudum is not an available name, and therefore the same name may be made available later for the same or a different concept; in such a case it would take authorship and date from that act of establishment, not from any earlier publication as a nomen nudum).

nom. oblit. = nomen oblitum (a forgotten name, an unused senior synonym rejected under the provisions of the International Code of Zoological Nomenclature. Formerly a senior synonym not once applied to a particular taxon as its presumably valid name for the immediately preceding 50 years (other than in a synonymy, listing in an abstracting publication or a nomenclator) and to which taxon has been currently been applied a junior synonym by at least 5 different authors in at least 10 publications during the immediately preceding 50 years. Such a name, unless otherwise ruled, is to be rejected for the purposes of the Law of Priority but not for those of the Law of Homonymy. No longer recognised. After 1 January 2000 applied to a name, unused since 1899, which as a result of an action taken under the Code does not take precedence over a younger synonym or homonym in prevailing usage; the younger name which takes precedence over the nomen oblitum may be called a nomen protectum. A nomen oblitum remains an available name).

nom. provis. = nomen provisorium (provisional name, a name proposed provisionally in anticipation of the acceptance of the taxon concerned at a future date).

nom. rejic. = nomen rejiciendum (1) rejected name, any name (other than the valid name of a taxon) which has been officially rejected under the provisions of the International Code of Zoological Nomenclature, 2) a family or genus name that should replace another well-known name but which is rejected in favour of a nomen conservandum, q.v.).

nom. non planta = nomen sed non planta (used to indicate that a author has applied the name to a taxon other than that to which the type of the basionym, q.v., belongs).

nom. rev. = nomen revivisco (name revived, used of a name revived or reinstated, e.g. from an earlier synonymy).

nom. superfl. = nomen superfluum (superfluous name, a name incorrectly applied to a taxon. When first applied the taxon included the type of another name which should have been used under the provisions of the International Code of Zoological Nomenclature).

non al. = non aliorum (not of other authors).

nov. = novum, meaning new.

nov. n. = nomen novum (a new name which is published to replace an earlier name (and valid only if the latter is preoccupied) and which is expressly proposed as a replacement name; a new name, not to be confused with a new species, or a new genus, etc., which represent new taxa. Commonly applied to names proposed to replace junior homonyms)).

nov. sp. = nova species, meaning new species (species nova is to be preferred).

nr = number.

NS = new style (indicates the Gregorian or modern western calendar. Some older fish literature, especially Russian, is dated by the Julian calendar or old style. The Gregorian calendar came into use in Catholic Europe in 1582 (the day after October 4 became October 15), in England in 1752 but only in 1918 in Russia).

NTZ = no take zone ( a marine protected area where catches or removal of organisms are prohibited).

O = Ordovician, a geological period within the Palaeozoic ca. 504-441 million years ago.

OA = the upper, ventro-lateral row of photophores running above the ventral series from just behind the operculum to above the anal fin.

OP = 1) photophores just posterior to the end of the upper jaw in Myctophidae, 2) photophores on the gill cover, one near the anterior base of the preopercle, one in front of the anterior part of the subopercle, and one antero-dorsally to the operculum, also called maculae operculares, 3) opercular canal, q.v.

op. cit. = opera citato.

ORB = photophores near the eye; one antero-ventral to the eye is called the suborbital (or preorbital) and one postero-ventrally is called the postorbital.

orth. mut. = orthographia mutata (with an altered spelling).

OS = old style (time reckoned according to the Julian calendar; subsequently replaced by new style (reckoned according to the Gregorian calendar and now in use in the West). Most scientific papers operate on the Gregorian or new style calendar but Russia only adopted the Gregorian system in 1918 and some of their nineteenth century papers and records are asynchronous by 11 days. This can be confusing when attempting to validate type material since catalogues, publications and labels with the types in jars can have different dates. Abbreviated as OS. See also new style).

oz = ounce (28.3495 g avoirdupois).

oz tr = troy ounce (31.103 g).

P = 1) abbreviation for pectoral fin.

P = 2) Permian, a geological period of the Palaeozoic ca. 290-245 million year ago.

P = 3) symbol for the (parental) generation in which fertilization produces hybrids.

P1 = pectoral fin.

P2 = pelvic fin; V is an alternate abbreviation.

p = probability.

pm or p.m. = post meridiem, for after noon indicating time after 12.00 noon.

p. p. = pro parte (in part, used in author citations to show that only part of a taxon, as defined by a previous author, is being referred to by the writer).

p.p.m. = parts per million.

p.p.t. = parts per thousand.

PAH = polycyclic aromatic hydrocarbons, chemicals found in fish products as environmental contaminants, usually at low concentrations, much higher where there is contamination from petroleum and petroleum products. Found in smoked fish at 10 times or more than unsmoked fish. Some PAHs are carcinogenic.

pb = personal best, the largest fish of a particular species caught by an angler. Seen particularly in British fishing magazines.

pers comm. = personal communication (unpublished information communicated to the author verbally).

pers. obs. = personal observation (information or data obtained by the actions of the author).

PFD = personal flotation device.

pH = a measure of how acidic or alkaline a solution is, i.e. the concentration of hydrogen ions in a solution (log to base10 of the reciprocal of the hydrogen ion concentration). pH 7.0 is neutral, lower values are acidic and higher values are alkaline. Acid rain decreases the natural pH of rivers and lakes. Some fish require a specific pH, others will live at wide range of values.

pit = PIT.

PIT = Passive Integrated Transponder tags (an integrated microchip that is programmed to include specific fish information and inserted into the body cavity of the fish and decoded at selected monitoring sites. Used for identifying individual fish for monitoring and research purposes. The tag is activated by passing a hand-held scanner over the fish).

PKD = proliferative kidney disease (a temperature-dependent disease of salmonids caused by a myxosporean protozoan causing gross changes in the kidney).

PLO = maculae suprapectorales (a photophore above the base of the pectoral fin in Myctophidae).

PM = hyomandibular canal (or preoperculo-mandibular canal, the cephalic lateral line canal extending along the preoperculum and lower jaw. The preopercular and mandibular parts of the canal may be disconnected).

P_MAX = the probability of re-building a fish stock by T_MAX. A higher P_MAX probability is associated with a lower fishing mortality rate.

PO = maculae pectorales (a row of photophores on the breast in front of the pelvic fin in Myctophidae).

Pol = maculae posterolaterales (ventrolateral photophore(s) above the AO series which lie along the base of the anal fin but below the lateral line in Myctophidae).

ppb or p.p.b. = parts per billion.

ppm or p.p.m. = parts per million.

ppt or p.p.t. = parts per thousand.

Prc = maculae praecaudales (photophore(s) on the lower half of the caudal peduncle at the base of the caudal fin in Myctophidae).

PSU or psu = practical salinity unit (the ratio K of the electrical conductivity of a sea water sample of 15°C and the pressure of one standard atmosphere, to that of a potassium chloride (KCl) solution, in which the mass fraction of KCl is 0.0324356, at the same temperature and pressure. The K value exactly equal to one corresponds, by definition, to a practical salinity equal to 35. In this definition, salinity is a ratio and parts per thousand (‰) is therefore no longer used, but an old value of 35‰ corresponds to a value of 35 in the practical salinity. Practical salinity is a ratio and strictly no units should be used but often PSU or psu is added to the value).

pt = pint (473.17 cm³, U.S. liquid).

pt_BI) = pint (568.26 cm³, Imperial).

pt, dry = pint (550.6 cm³, U.S. dry).

PUFA = long-chain polyunsaturated fatty acids (omega-3-fatty acids) found in fishes.

PVA = 1) population viability analysis (a quantitative analysis which estimates the extinction probability of a species or population based on the known life history and specified management or non-management options),

PVA = 2) polyvinyl alcohol, a water soluble plastic used by anglers in Europe as bags to hold ground bait or as string for tying on boilies, q.v., or pellets. The bags or strings dissolve gradually in water and release the baits to attract fish. See PVA bag and PVA tape.

PVO = maculae subpectorales (photophores below the pectoral fin and above the PO row in Myctophidae).

Q = Quaternary, a geological period of the Cenozoic Era ca. 1.6-0 million years ago comprising the Pleistocene and Holocene (or Recent).

q (or q) = catchability (the extent to which a stock is susceptible to fishing, the part of a stock that is caught over a defined unit of time or fishing effort; quantitatively, the proportion of the stock removed by a defined unit of fishing effort. In pelagic fishes, an inverse function of stock biomass. When it is 0.01 or less it can be used as an instantaneous rate in measuring population change (Ricker, 1975). Also called catchability coefficient, force of fishing mortality).

Q₁₀ = temperature coefficient (the quantitative increase or decrease in fish metabolic rate for each ten degree change in body or environmental temperature).

q.e. = quod est, meaning which is.

q.v. = quod vide, meaning which see.

ql = quintal (1) an old measure of dried, salt cod for sale, 112 pounds or 50.8 kg, 2) a hundredweight, either 112 or 100 pounds, according to the scale used, 3) also a modern measure equal to 100 kg or 220.46 pounds).

r or r = 1) 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), 2) intrinsic growth rate (how much a population can grow between successive time periods when not slowed down by competition. Often estimated with production models and plays an important role in evaluating the sustainability of different harvest levels and the capacity to recover after depletion).

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.

recent. = recentiorum, meaning of recent authors.

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

rkm = the distance between two points along a river.

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

ROV = 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).

S = 1) survival rate (number of fish alive after a specified time interval, divided by the initial number, usually on a yearly basis (Ricker, 1975).

S = 2) siemens, a measure of conductivity, q.v.

S = 3) Silurian, a geological period within the Palaeozoic ca. 441-113 million years ago. Most of the major groups of fishes are thought to have originated in the Early Silurian.

s = second.

S₁ = a salmon smolt that is transferred to sea water for on-growing after 1 year in fresh water (S₂ = after two years).

s.a.p. = specific action potentiality (the state of an animal responsible for its readiness to perform the behavior patterns of one instinct in preference to all other behavior patterns; level of motivation).

s. ampl. = sensu amplificato, meaning in an enlarged sense.

s. l. = sensu lato meaning in the broad sense.

s. lat. = sensu lato (in the broad sense; using a taxon inclusively to embrace two or more taxa which other authors consider distinct).

s. n. = sine numero, meaning without a number, unnumbered.

s. s. = sensu stricto, meaning in the strict sense.

s. str. = sensu stricto, meaning in the strict sense, in the narrow sense.

s-g. = subgenus.

s-gg. = subgenera.

s. n. = sine numero (without number; used to indicate absence of a collector's number from a list of specimens).

s. s.= sensu stricto (in the strict sense, in the narrow sense; using a taxon restrictively, excluding taxa which other authors include).

s. str. = sensu stricto (in the strict sense, in the narrow sense; using a taxon restrictively, excluding taxa which other authors include).

SAO = maculae supraanales (a sloping, ventro-lateral row of photophores above the anal fin origin in Myctophidae.

sc. = scilicet, meaning namely.

sched. = scheda = label; used for the label on a specimen.

sec. = secundum, meaning according to.

sens. = sensu, meaning in the sense of.

sens. amplo. = sensu amplificato (in an enlarged sense).

sens. lat. = sensu lato (in the broad sense; using a taxon inclusively to embrace two or more taxa which other authors consider distinct).

sens. str. = sensu stricto (in the strict sense, in the narrow sense; using a taxon restrictively, excluding taxa which other authors include).

seq. = sequens, meaning following.

ser. = series, meaning series.

SL = standard length (the measurement from the most anterior tip of the body to the midlateral posterior edge of the hypural plate (in fish with a hypural plate) or to the posterior end of the vertebral column (in fish lacking hypural plates). It may be restricted to the tip of the snout if the lower jaw projects. The base of the caudal fin (end of the vertebral column or posterior edge of the hypural plate) is determined by flexing the tail up while the caudal peduncle is held down. The resultant wrinkle or caudal flexure indicates the caudal base. It may also be determined by probing or dissection. Sometimes the posteriormost point is the last scale, the last pored scale or the beginning of the caudal fin rays. It is the usual scientific measurement for length of a fish except in Amphioxi, Myxini, Petromyzontiformes, Elasmobranchii and Holocephali. This measurement is used because long-preserved fish often lose the tips of the caudal fin rays through breakage after the desiccation effect of alcohol. See total length and fork length. In Holocephali the length is usually taken from the tip of the snout to the origin of the upper caudal fin because the caudal filament breaks off frequently. In Scaridae it is taken back to the rear margin of the second to last lateral line scale {because the large scales obscure the point of caudal flexure. Also abbreviated as sl or Sl.).

SO = supraorbital canal (the cephalic sensory canal (q.v.) extending from above the eye to the nostrils).

sp. (spp. plural) = species (singular and plural) (biologically, a group of populations of actually or potentially interbreeding organisms which are reproductively isolated (by behavior, ecology, morphology or physiology) from other such groups. Taxonomically, the name of a category of organisms below the genus-group; an individual taxon of the category "species", e.g. Perca fluviatilis. Morphologically, the smallest group of animals that can always be separated (+95% of the specimens or all of the specimens) from other such groups by morphological characters (other than sex or individual genes) – does not include sibling species. A species is a subjective unit insofar as it is based on only a sample of the population and insofar as the point of separation where there is some overlap must be arbitrary. A nominal species is a named species, objectively defined by its type-specimen).

sp. indet. or sp. ind.= species indeterminata (an indeterminate species; one which cannot be recognized from its original description).

sp. nov. or sp. n. = species nova (new species; given after the scientific name instead of the authority (who as author of the article is assumed to be the authority)).

SPA = sequential population analysis (methods of back-calculating stock sizes, recruitment levels, and fishing mortality for different ages or years using catch-at-age data. The past history and present abundance of a stock).

spm = specimen.

sqm = scales counted along the side of the body as if in a lateral line, from the Latin squama for scale.

SPR = spawning potential ratio (the number of eggs that could be produced by an average recruit in a fished stock under a given regime divided by the number of eggs that could be produced by an average recruit in an unfished stock. This may also be expressed at the spawning stock biomass per recruit (SSB/R) of a fished stock divided by the SSB/R of the stock before it was fished. Also called percentage maximum spawning potential or %MSP).

SRR = stock recruitment relationship (the relationship between the level of parental biomass, e.g. spawning stock size, and subsequent recruitment level. Difficult to determine accurately).

SSB = spawning stock biomass (the total weight of the fish in a stock that are old enough to spawn; the biomass of all fish beyond the age or size class in which 50% of the individuals are mature. May be used instead of measuring egg production).

SSB/R = spawning stock biomass per recruit (the spawning stock biomass divided by the number of recruits to the stock. It is the expected lifetime contribution to the spawning stock biomass for a recruit of a specific age, e.g. per age 2 individual).

ssp. = one subspecies.

sspp. = more than one subspecies.

ST = occipital canal (supratemporal canal (the cephalic lateral line canal (q.v.) running across the top of the head joining the lateral canals).

st. = status, meaning rank.

stat. = status, meaning rank.

stat. nov. = status novus, meaning new status or new rank.

stat. rev. = status revivisco, meaning status revised.

STP = sodium tripolyphosphate (an additive used on fish to retain moisture).

subgen. = subgenus (1) a category of the genus-group subordinate to genus, 2) an individual taxon of the category "subgenus", e.g. Clupea).

subsp. = subspecies (1) a category of the species-group subordinate to species; the lowest category recognized by the International Code of Zoological Nomenclature, 2) an individual taxon of the category "subspecies". Allopatric populations of organisms differing genetically from other such populations and tending because of barriers not to interbreed with other such populations, although capable of doing so. Defined variously as differing at a level of 75-90% or 93% from (all or any) other such adjacent populations).

Suo = maculae supraorbitalis (the photophore on the posterodorsal border of the orbit in Myctophidae).

supra cit. = supra citato, meaning cited above.

syn. = synonym or synonymy (each of two or more names with different spelling applied to one and the same taxon. The junior synonym is that with the later, the senior synonym is that with the earlier, publication date. Objective synonyms are the two or more synonyms used on the same type. Subjective synonyms are the two or more synonyms based on different types, but which are regarded as referring to the same taxon by those zoologists who hold them to be synonyms).

syn. nov. = synonymum novum (new synonym, used when a name is treated as a synonym for the first time).

T = Tertiary, a geological period of the Cenozoic Era ca. 65-16 million years ago comprising the Palaeocene, Eocene, Oligocene, Miocene and Pliocene.

T_R = Triassic, a geological period of the Mesozoic Era ca. 245-210 million years ago.

t = tonne ( metric ton, 1000 kg, 2204.62 pounds (lb), 0.984 long tons, 1.102 short tons. Often spelled ton, confusingly).

t. = teste, meaning according to, on the evidence of; and for tomus, meaning volume.

t. c. = tomus citate, meaning in the volume cited.

tab. = tabula, meaning table.

TAC = total allowable catch, the weight of fish of a given species or type caught by commercial fishing in any year. The TAC is set by a government in an effort to manage the resource.

TACC = total allowable commercial catch; same as above.

TDS = total dissolved solids, a measure of water quality ( the total residue remaining after evaporation of a water sample filtered to remove suspended matter larger than 1.0 mm; inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates) and small amounts of organic matter that are dissolved in water, not suspended like wood pulp particles).

TED = turtle excluder device (any device used to exclude turtles from nets where they may drown; a grid of bars fitted to the mouth of the net allows fish and shrimps to enter but deflects the larger turtles).

ThRP = threshold reference point (indicates that the state of a fishery and/or a resource is approaching a target reference point (TRP) or a limit reference point (LRP), and that a certain type of action (usually agreed beforehand) needs to be taken. Fairly similar to a LRP in their utility, the ThRp specific purpose is to provide an early warning, reducing further the risk the the LRP or TRP are inadvertently passed due to uncertainty in the available information or inherent inertia of the management and industry systems).

TL = 1) total length (the greatest length of the whole body between the most anterior point of the body and the most posterior point, in a straight line, not over the curve of the body. Sometimes, when there are two equal lobes, the caudal rays are squeezed together and their tip is taken as the most posterior point, or the longest lobe is squeezed to the midline (maximum length or extreme tip length). Also an imaginary line may be drawn between the two lobe tips and length to its mid-point taken as the most posterior point (total auxiliary length or bilobular length). Usually the tip of the most posterior lobe of the fin in normal position is taken as the posteriormost point (total normal length or natural tip length). Total length is used in Amphioxi, Myxini, Petromyzontiformes, usually in Elasmobranchii and sometimes in other fishes. Standard length, q.v., is usually employed with Teleostei).

TL = 2) tolerance limit (a 24 hour TL₅₀ is the concentration of a chemical which kills (or effects in other specified ways) 50% of fish in 24 hours).

Tmax = lifespan (the maximum expected age, on average, for a species, cohort, stock, or a population in the absence of fishing. Smaller than maximum age although may be used in this sense. Abbreviated as Tmax in stock assessment models).

tom. = tomus, meaning volume.

Tmax = lifespan (the maximum expected age, on average, for a species, cohort, stock, or a population in the absence of fishing. Smaller than maximum age although may be used in this sense. Abbreviated as Tmax in stock assessment models).

TP = abbreviation for terminal phase in diandric fishes possessing two different types of males, a large, brightly-coloured and aggressive terminal phase (TP) and a smaller, drab and relatively non-aggressive initial phase (IP), e.g. in Thalassoma lunare (Labridae). The TP has priority access to food and spawning females. On the death or removal of a TP, the first-ranking IP becomes the next TP (after first checking the reef thoroughly to make sure the TP is gone).

tr. = transverse row of scales, diagonal scale row (the almost vertical rows of scales slanting backwards and downwards across the sides of the body. Divided into scales above the lateral line starting at the front of the dorsal fin (from, but not including, the scale in the middorsal row, to but not including, the lateral line scales) and below the lateral line similarly ending at the front of the anal fin. The number of transverse rows themselves along the body may also be counted).

TRAIL = Transgenerational Isotope Labelling, a stable isotope, e.g. barium, given to a female fish just before spawning so that the young fish have a chemical signature in their otoliths and can be tracked.

trans. nov. = translatio nova, meaning new transfer, and used to indicate that a taxon has been altered in position but retains the epithet from its name in the former position.

T_TARGET = the target year set by a policy for fish stock to be completely rebuilt.

TURF = territorial use right in fisheries.

ty = a thousand years.

typ. = typus meaning type.

typ. cons. = typus conservandus, a type to be conserved.

u (or u) = 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. (Ricker, 1975). Also called; fishing coefficient).

UDN = ulcerative dermal necrosis (a disease affecting salmonids returning from the sea to fresh water with head lesions. The cause is probably viral but the lesions are typically infected by bacteria and fungi).

ueq = microequivalents, e.g. 20 ueq/l = 1 mg/l CaCO₃.

UTM = Universal Transverse Mercator = a system for indicating locations on the Earth's surface based on ground distances. Locations are designated in terms of distances in metres east of the centre of a UTM zone and north (or south) of the equator. The earth is divided into sixty zones, each 6 degrees of longitude wide. Each zone is projected onto a Transverse Mercator projection. UTM zone 1 extends from 180° to 174°W. Each zone extends from 80°S latitude to 84°N.

V = 1) abbreviation for ventral (pelvic) fins.

V = 2) abbreviation for vulnerable in the IUCN Categories, q.v.

V = 3) abbreviation for utilised stock (the part, by number, of the fish alive at a given time, which will be caught in the future (Ricker, 1975)).

v = 1) abbreviation for vide, meaning see or visum, meaning seen.

v = 2) abbreviation of volume.

v = 3) abbreviation of varietas, meaning variety.

v = 4) abbreviation of vel, meaning or.

v = 5) versus, in contrast to. Also as vs.

v. et. = vide etiam, meaning see also.

VD trawl = Vigneron-Dahl trawl (the usual rig of an otter trawl with long cables that frighten fish toward the net).

VHS = Egtved disease (an acute or chronic disease of salmonids, such as rainbow trout in farm ponds, causing loss of appetite and of schooling behaviour, darkened colour, bleeding, hyaline gills and exophthalmia. It is associated with temperature changes and with the late winter and spring seasons when temperatures are below 8°C. Also called viral haemorrhagic septicaemia).

VLO = maculae supraventrales (a photophore above the ventral fin in Myctophidae).

VMS = vessel monitoring system, a system for tracking fishing vessels electronically using satellites.

VO = maculae ventrales (a row of photophores on the abdomen behind the ventral fin in Myctophidae).

W_r = 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).

W_s = standard weight, the 75th percentile of the weights of a given species within specified length increments.

XBT = expendable bathy-thermograph, an instrument that records water temperature with depth.

Y' = surplus production (production of new weight by a fishable stock, plus recruits added to it, less what is removed by natural mortality. Usually estimated as the catch in a given year plus the increase in stock size or less the decrease (Ricker, 1975). Also called natural increase, sustainable yield, equilibrium catch.

Y_s = maximum sustainable yield (the average or maximum catch that can be removed under existing environmental conditions over an indefinite period without causing the stock to be depleted, assuming that removals and natural mortality are balanced by stable recruitment and growth. Abbreviated also as MSY. Also called maximum equilibrium catch, maximum sustained yield, sustainable catch).

Y/R = yield-per-recruit (the expected lifetime yield-per-fish of a specific age, e.g. per age 2 individual. For a given exploitation pattern, fishing regime, rate of growth and natural mortality, an expected equilibrium value of Y/R can be calculated for each level of fishing mortality (F)).

ya = years ago.

ybp = years before present.

yd = yard (0.914 m).

YE or Y_E = the yield in weight taken from a fish stock when it is in equilibrium with fishing of a given intensity, and (apart from effects of environmental variation) its biomass is not changing from one year to the next (Ricker, 1975). Also called sustainable yield, equivalent sustainable yield.

YOY = young-of-the-year (members of age group zero, from transformation to juvenile until January 1 in the Northern Hemisphere or July 1 in the Southern Hemisphere (Hubbs, 1943)).

yr = year.

yrs = years.

Z = instantaneous rate of mortality (the natural logarithm (with sign changed) of the survival rate. The ratio of number of deaths per unit of time to population abundance during that time, if all deceased fish were to be immediately replaced so that population does not change (Ricker, 1975). Also called coefficient of decrease).

Z = total mortality rate ( the number of fish which die during a year or season, divided by the initial number. Also called actual mortality rate, coefficient of mortality).

z = instantaneous rate of recruitment (number of fish that grow to catchable size per short interval of time, divided by the number of catchable fish already present at that time. Usually given on a yearly basis, i.e. the figure just described is divided by the fraction of a year represented by the short interval in question. This concept is used principally when the size of the vulnerable stock is not changing or is changing only slowly, since among fishes recruitment is not usually associated with stock size in the direct way in which mortality and growth are (Ricker, 1975)).

Z' = disappearance (the rate of decline in numbers of fish caught as fish become less numerous or less available. Often calculated from catch curves).

Zmbp = level of total mortality at which the maximum biological production is obtained from the stock.

© Brian W. Coad (www.briancoad.com)

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