Species Accounts
Petromyzontidae - Lampreys - Lamproies
Lampreys are found in cooler waters of the northern and southern hemispheres. There are 41 species with 11 recorded from Canadian freshwaters and along all three coasts. There are 4 species in the NCR.
Lampreys are jawless fishes, lacking bone in the skeleton and having 7 pairs of pore-like gill openings. The eel-like body has no pectoral or pelvic fins. There are 1 or 2 dorsal fins and a caudal fin. An anal fin-like fold develops in spawning females. Eyes are large. The mouth is a suctorial disc armed with rows of horny teeth. There are also teeth on the tongue. The median nostril, or nasohypophyseal opening, is not connected to the mouth. There is a light-sensitive pineal organ or "third eye" behind the nostril. The skin is covered in mucus which is poisonous to fishes and humans. Lampreys are edible if the mucus is cleaned off. Lampreys have a body form similar to the more familiar but unrelated eels (Anguillidae). Occasionally there are references in articles to lamprey-eels, but there is no such fish; there are lampreys and there are eels, quite distinctive organisms.
Their origins lie at least 300 million years in the past. Their tooth arrangement is used in classification and identification along with the number of myomeres (muscle blocks along the body). Both tooth counts and the number of cusps are used in particular those on the supraoral lamina (bar above the "mouth", the oesophageal opening), the infraoral lamina (bar below the "mouth") and the row of teeth on both sides of the "mouth". There are various series of smaller teeth and of course teeth on the tongue. Larval lampreys lack teeth and are particularly difficult to identify and their determination often requires specialist knowledge. Characters for the larvae include counts of myomeres and pigmentation patterns.
Lampreys have an unusual life cycle. Adults die after spawning and the eggs develop into a larva, known as an ammocoete, which lacks teeth, has an oral hood, eyes covered by skin, a light-sensitive area near the tail, and is a filter-feeder while buried in mud and silt. Fleshy tentacles in the oral hood are used to extract minute organisms from the water, such as algae (desmids and diatoms) and protozoans. After several years (up to 19 but usually 7 or less), the ammocoete transforms into an adult with enlarged eyes, teeth, a different colour and pronounced dorsal fins. The body shrinks during this metamorphosis and adults are only larger than ammocoetes if they feed. The adult may be a parasite on other fishes and marine mammals, or non-feeding. Individuals of a species may or may not be parasitic and different species may be parasitic or non-parasitic. The non-parasitic species are believed to have evolved from a parasitic species so there tends to be closely related parasitic/non-parasitic species pairs.
Parasitic adults feed mostly on other fishes, attaching to their bodies by suction and using their toothed tongue to rasp through the skin and scales to take blood and tissue fragments. Prey is detected by sight but some lampreys attach to hosts during the night. Perhaps this reduces their own predation risks and enables them to approach their quiescent hosts more easily. Lampreys tend to select larger fish as these survive longer and ensure a good food supply. The flow of blood is aided by an anti-coagulant in lamprey saliva called lamphedrin which also serves to break down muscle tissue. Large, anadromous lampreys are usually attached ventrally near the pectoral fins while small, freshwater species, such as the Chestnut Lamprey and the Silver Lamprey, are usually attached dorsally. Dorsal attachment reduces abrasion of the lamprey in shallow water. Ventral attachment results in greater food intake for the lamprey. Lamprey attacks leave a characteristic round scar and can be a major problem for commercial fisheries by damaging food species and leaving them too unsightly to market. The attack may weaken or even kill the host. Weakened fishes are more prone to diseases and the wound provides an easy path of entry for them. Even fishes with heavy scales like Gar Family members are attacked. A single 16 kg Lake Sturgeon has been recorded with 61 Silver Lampreys parasitising it, although it was estimated that this would not kill the host by draining its blood.
Lampreys may move into or up streams to spawn. The scientific name of the family means "stone sucker" and the adult mouth is used to hold or suck onto stones as well as on prey. This suction enables the lamprey to maintain position in fast-flowing streams when spawning and even to climb over rapids and small waterfalls. Usually spawning occurs in shallow water with a moderate current, a bottom of gravel and nearby sand and silt for the ammocoetes to live in. Either or both sexes build a nest by moving gravel around with their sucking mouths and by thrashing their bodies. A shallow depression is formed, about 0.5-1 metre long. Spawning often occurs in groups and several males may attach to a female with the sucking disc. The process takes several days as only a few white to yellow eggs are laid at a time. The eggs are adhesive.
Adult lampreys are usually caught when attached to a host or when spawning. Electro-shocking will force ammocoetes out of their u-shaped burrows to the surface and immobilise adults. They sometimes attach to boats and occasionally to swimmers when their skin is cool but are easily removed, perhaps because nobody has left a lamprey on their skin long enough to see if the tongue starts rasping flesh!
Lampreys have been used for food by various native peoples in Canada and are popular in Japan. They have been considered a delicacy and can be smoked, set in aspic or cooked in a variety of ways. Henry I of England is said to have died of a "surfeit of lampreys".
Chestnut Lamprey / Lamproie brun
Ichthyomyzon castaneus Girard, 1858
Taxonomy
Other common names include Western, Northern, Silver, and Brown Lamprey, Hitchhiker, Seven-eyed Cat and Bloodsucker. Ichthyomyzon is from the Greek ichthys for "fish" and myzon for "sucking" and castaneus is Latin for "chestnut-coloured".
Key Characters
This lamprey is distinguished by having a single, notched dorsal fin, by having 1 or more lateral disc teeth with 2 cusps (1-10 bicuspid circumorals, usually 6).
Description
There are 47-57 trunk myomeres, usually 51-54. Teeth are sharp, strong and curved. The band of teeth below the mouth is a broad, curved bar with 6-11 tooth cusps. There are 4 pairs of inner lateral teeth, usually bicuspid and sometimes tricuspid.
Colour
Adults are dark grey to olive, or yellow-brown, sometimes mottled, occasionally a chestnut colour which gives them their name. The lateral line organs are black in adults, though only weakly in young adults. They become blue-black when spawning. Ammocoetes are overall lighter in colour. Ammocoetes are paler and have no pigment, or are only weakly pigmented, on the lateral line organs.
Size
Attains 38.0 cm.
Distribution
Found in central North America from southeastern Saskatchewan, west-central Manitoba and eastern Lake Huron tributaries of Ontario south to the Gulf of Mexico centred on the Mississippi-Missouri basin.
Origin
This species entered the NCR from a Mississippian refugium.
Habitat
Found mostly in medium-sized streams although adults may be found in large rivers and dams. Ammocoetes prefer vegetated areas with current unlike other species.
Age and Growth
Ammocoete life span is unknown, but is presumed to be 5-7 years with a maximum age for the species of about 8 years.
Food
Transformed adults do not feed over their first, and one subsequent, winter and feed most heavily from April to October. They spawn and die the following summer. This species has been caught attached to a Lake Sturgeon or a Northern Pike in Brewery Creek in the NCR (the data were uncertain), most probably the latter given the locality (Renaud and de Ville, 2000). The eggs of this lamprey are eaten by darters, minnows and crayfishes.
Reproduction
Peak spawning is in early to mid-June at 15.6-22.2°C in Michigan and takes place at night in small to large groups (up to 50). A female attaches to a stone and begins rapid quivering motions. A male attaches to the head of the female and wraps its tail around her body. Up to 5 lampreys can attach, each to the head of the one before it. Up to 50 lampreys can be found in a single nest as nests tend to merge during excavation. The nest sites are in small streams. A single nest can be 2.8 m long and 1 m wide. The spawning continues through the night but by the afternoon of the following day, lampreys have left the nest. A large female had 42,000 eggs. Eggs are elliptical, 0.64 mm by 0.56 mm.
Importance
This lamprey was accorded a status of "vulnerable", now "Special Concern", in 1991 by the Committee on the Status of Endangered Wildlife in Canada. It is not as economically significant as the Silver Lamprey because of its habitat, size, abundance and distribution in Canada. Elsewhere it is known to attack Brook Trout and can stay attached for over 18 days, killing the host. Trout destruction has been reported as reaching 23.5 kg/ha or about one-third of the trout available to anglers. They are a favoured food of Burbot and trouts as well as other fishes.
Northern Brook Lamprey / Lamproie du nord
Ichthyomyzon fossor Reighard and Cummins, 1916
Taxonomy
Other common names include Michigan Brook Lamprey and Blood Sucker.
Key Characters
This species is distinguished from other Canadian lampreys by having a single dorsal fin, teeth along the side of the mouth with 1 cusp, 2 knob-like and blunt cusps on the bar above the mouth, 6-11 knob-like and blunt cusps on the bar below the mouth, and lateral lines organs unpigmented.
Description
Trunk myomeres number 47-58, usually 51-54. The sucking disc is narrower than the body.
Colour
Adults are dark slate grey to brown above, pale grey, silvery or white on the belly. The area under the gill pores may be orange. Fins are grey to yellow or brown. The eye is bluish. Lateral line organs lack black colouration. In ammocoetes, the caudal fin and head are weakly pigmented.
Size
Attains 28.2 cm and 9.9 g, but usually no larger than 16.0 cm (Fortin et al., 2009).
Distribution
Found in the Hudson Bay drainage of Manitoba, the Great Lakes basin of Ontario and the upper St. Lawrence River basin in Québec south to Kentucky and Missouri. The presence of this species in the NCR is uncertain (Coad, 1986b). Adults are not easily caught with nets because of their elongate shape and, being non-parasitic, cannot be found attached to fish. Ammocoetes can be caught in mud or sand by electroshocking but are very difficult to identify and distinguish from the Silver Lamprey. Spawning adults would be readily identifiable but attempts to catch them have failed as spawning takes place in early spring when water levels are high, conditions are difficult of access in flooded areas of uncertain depth. Lanteigne (1981; 1992) mapped the Northern Brook Lamprey at Ottawa but Rohde and Lanteigne in Lee et al., (1980) did not.
Origin
This species entered the NCR from a Mississippian refugium (Mandrak and Crossman, 1992).
Habitat
This is a non-parasitic species found in warmer streams and smaller rivers than the American Brook Lamprey or along the margins of larger rivers. It is reported as common in turbid streams. Ammocoetes prefer a soft bottom over firm sand but not the extremely soft mud of backwaters. They are most numerous at 15-61 cm depths. They move only if their habitat is disturbed or food becomes short. This movement takes place mostly at night when predators are less active. Low fertility and relatively low mobility as a non-parasitic species make it vulnerable to natural and man-made habitat changes.
Age and Growth
Ammocoetes live 3-7 years and may "rest" for a year without feeding before transformation to the adult in August to September. Maximum life span is about 8 years.
Food
Ammocoetes filter feed on desmids, diatoms and protozoans. Food may also be taken from the sediment. The gut degenerates at the beginning of transformation from ammocoete to adult and for a period of 8-9 months no food is taken. Various predatory fish will take ammocoetes and spawning adults on nests are most vulnerable.
Reproduction
Spawning occurs from late May to mid-June at 12.8-23.3°C in Michigan without a migration. The nest is constructed among large stones or gravel to create a cavity. Unusual vertical body movements, and transport of gravel using the sucking disc, excavate a 10 cm long nest. Up to about 2,000 eggs of 1.0-1.2 mm diameter are produced and adhere to silt-free sand. Incubation takes 9 days at 18°C. The post-spawning period lasts only a few days and then all the spawning adults die.
Importance
Ammocoetes have been sold as bait in Quebec but this now prohibited. This species was accorded the status of "Special Concern" in 1991 by the Committee on the Status of Endangered Wildlife in Canada (Lanteigne, 1992; COSEWIC, 2002). Fortin et al. (2009) review its status in Quebec and found that its low fecundity and low dispersal ability make it poorly adapted to withstand changes in the environment.
Silver Lamprey / Lamproie argentée
Ichthyomyzon unicuspis Hubbs and Trautman, 1937
Taxonomy
Other common names include Northern Lamprey and Brook Lamprey. The Northern Brook Lamprey is its non-parasitic relative.
Key Characters
This species is distinguished by having a single dorsal fin, all teeth along the sides of the mouth with 1 cusp, (0-2 bicuspid circumorals, usually none), a sharp bicuspid tooth on the bar above the mouth, and 5-11 sharp, triangular cusps on the bar below the mouth.
Description
Teeth are sharp and yellow. Trunk myomeres number 47-57, usually 49-52. The sucking disc is wider than the body.
Colour
Adults are brown, blue-grey or bluish with silvery overtones and with a blue-grey or silver belly. Lateral line organs are black in specimens greater than 150 mm length. Adults become darker as the spawning season approaches and are blue-back near the end of spawning. Ammocoetes are pale although the caudal fin and head are strongly pigmented.
Size
Attains 38.1 cm.
Distribution
Found from Manitoba, through southern Ontario around the Great Lakes to western Québec and as far south rarely to Mississippi. In the NCR this species is known only from the Ottawa River and mouths of tributary rivers. Small (1883) reports Icthyomyzon Argenteus (sic) (= I. unicuspis) from the "Rideau, Gatineau, the Lievres, and streams running into these rivers" but this has not been borne out by field work since then
Origin
Silver Lampreys entered the NCR from a Mississippian refugium.
Habitat
This is a parasitic species found in the larger rivers and lakes. Ammocoetes live in burrows in soft bottoms.
Age and Growth
Ammocoetes live 4-7 years before beginning transformation in late fall. Adults live 12-20 months and may migrate to a lake to feed. Females grow faster than males and attain a larger size.
Food
Ammocoetes filter-feed phytoplankton and other small organisms from the water. Adults are parasites on Lake Sturgeons, Brown Bullheads, American Eels, White Suckers, Silver Redhorses and Shorthead Redhorses (McAllister and Coad, 1975), on Northern Pike (attached to the inside of the branchial cavity of one pike, C. B. Renaud, pers. comm., 2002) and on Muskellunge (Renaud, 2003) in the NCR. Marks per host based on 15 Muskellunge from the Ottawa River from Ottawa to Hawkesbury varied between 1 and 31, with a mean of 10.6. 84.6% of the Muskellunge had marks on the dorsal surface, 46.2% laterally and 15.4% ventrally. The position of attachment was thought to be a consequence of the predatory behaviour of the Muskellunge, lying in concealment with the belly less exposed than in pelagic species, and perhaps to avoid detachment or injury by abrasion on the substrate. The wounds on the Muskellunge suggest blood feeding as they were shallow, rather than flesh feeding. The lampreys fed actively from at least 21 June to 30 October when captures with fresh marks were made.
Reproduction
Both sexes construct the nest in gravel in running water. Spawning occurs in May-June, peaking in early June, at 12.8-22.8°C in Michigan. Up to 65,000 eggs of 1.0 mm diameter may be produced. The eggs hatch after 7-10 days, depending on water temperature.
Importance
The ammocoetes are used as bait for sport fish.
American Brook Lamprey / Lamproie de l'est
Lampetra appendix (DeKay, 1842)
Taxonomy
Also called Brook Lamprey or Small Black Brook Lamprey. Scientific names used in other works that may be this species are Lampetra lamottenii Le Sueur, 1827 and Lampetra wilderi Jordan and Evermann, 1896. The former name has priority but there is some confusion over Le Sueur's application of this name and L. appendix is the next available name. Lampetra is from the Mediaeval Latin for "lamprey" and appendix is Latin for "appendage", probably referring to the prominent urogenital papilla of adult males.
Key Characters
This species is distinguished by having 2 dorsal fins, the bar above the mouth with 2-3 pointed cusps, and teeth along each side of the mouth bicuspid and pointed.
Description
Trunk myomeres number 63-74. The bar below the mouth has 6-10 cusps. Teeth are generally blunt and not as sharp as in the parasitic Silver Lamprey. Shrinkage of adults over winter from non-feeding almost closes the gap between the dorsal fins.
Colour
Adults are blue-grey when spawning with orange tinges on the head, back, tail and fins. Otherwise brown or lead-grey is the overall colour, the belly is white to light grey or silvery and clearly set off from the flanks. Fins are yellowish with the caudal fin darkest near the base, becoming lighter towards the margin. Ammocoetes are pale brown and have a whitish band above the branchial openings.
Size
Attains 31.7 cm (perhaps 35 cm) but these were "giants" which may have fed parasitically. Usually up to about 21.7 cm.
Distribution
This species is found from the Great Lakes basin of Ontario and the Upper St. Lawrence River basin in Québec southwards to Virginia, Tennessee and Missouri.
Origin
This lamprey entered the NCR from possibly a Mississippian refugium or Atlantic coastal refugium (Mandrak and Crossman, 1992).
Habitat
This is a non-parasitic species found in cooler (9-12°C) small streams and rivers than the Northern Brook Lamprey. It is sensitive to environmental change and prefers water that is clean and free of silt. Around Kettle Island and Upper and Lower Duck Islands in the large Ottawa River it is found unusually in sandy areas at 13-25°C (Lanteigne et al., 1981). It does not migrate.
Age and Growth
Ammocoetes live 4-6 years (perhaps 7.5 years) and transformation begins in the fall and continues over winter. The adult shrinks without food from parasitism.
Food
Adults do not usually feed and ammocoetes filter fine particles from the water.
Reproduction
Spawning occurs in mid-May to early June in Québec at 17°C and in Ontario in April-May. In Minnesota it occurs during late April and early May at 8.7-15.5°C. In Delaware spawning occurs in March-April at 6.8-12.0°C and in Michigan at 6.7-20.6°C in early May. Nests up to 30 cm long are built to a depth of 4 cm below the stream bottom. Current velocity in a Minnesota study was 14 cm s-1. The male begins construction and the oval to circular nests are in gravel and cobble between larger rocks or just upstream of riffles. Up to 25 lampreys may spawn in one nest with 5 times as many males present as females. The male uses his sucker to attach to the female's head, arching his body to bring his cloacal region close to the female's. Nests tend to be larger in deeper water, slower current and where larger spawning groups are found. Up to 5185 pale yellow to light green eggs about 1.2 mm in diameter are produced by each female. The eggs hatch in 9 days at 68°F.
Importance
Ammocoetes have been sold as bait for sport fish in Québec but this is no longer permitted.
© Brian W. Coad (www.briancoad.com)