Fishes of Canada's National Capital Region
Species Accounts
Lepisosteidae - Gars - Lépisostés
Gars are found in freshwaters of North and Central Americac and Cuba, sometimes entering brackish water and rarely the sea. There are 7 species with 2 in Canada and 1 in the NCR.
Gars have elongate jaws ("gar" is Old English for spear) filled with needle-like teeth. The ganoid scales are heavy, peg and groove hinged, non-overlapping, rhombic and plate-like, forming an effective armour. The tail is abbreviate heterocercal, externally appearing symmetrical but heterocercal internally. An upper tail lobe disappears with growth. There are 3 branchiostegal rays. The swimbladder has a rich blood supply enabling the fish to breathe air through a connection to the gut. A school of gars will break the water surface to breathe air at the same time and reduce the chances of attack by predators. Vertebrae are peculiar in having an opisthocoelous shape - anterior end convex, posterior end concave, a kind of ball and socket joint - which is almost unique in fishes and more usually associated with amphibians and reptiles. Dorsal and anal fins are near the tail. They lack spines but have fulcra (angled scales) on their anterior edge. The alligator gar of the southern U.S.A. and central America is the largest species at 3 m and over 158 kg.
Cretaceous and Eocene fossil gars are known from North America, Europe, India and West Africa. Fossil gars have been reported from Ellesmere Island in the Canadian Arctic Archipelago, well north of their modern distribution. An Upper Cretaceous coprolite (fossil faecal matter) from Alberta contained remains of gar scales and vertebrae. The gar was probably eaten by a crocodile, an indication of the different faunas that Lepisosteus species have lived with in Canada.
Gars favour shallow, weedy areas of lakes and rivers. They are ambush predators, lying still or quietly stalking prey until it can be seized by a sudden rush. Their food is almost entirely fishes. They make excellent subjects for home aquaria when young and for public aquaria when large. Gars are not sought after by anglers since they are hard to hook in their elongate, bony jaws, but a few enthusiasts specialize in their capture. They are not a commercial fishery item. Gar scales and skins are occasionally made into jewelery, picture frames, purses and boxes. The scales can be highly polished.
Longnose Gar / Lépisosté osseux
Lepisosteus osseus (Linnaeus, 1758)
Taxonomy
Other common names include Garpike, Northern Longnose Gar, Billy Gar, Billfish, Needlenose, Northern Mailed Fish, Pin-nose Gar, Bonypike, Scissorbill and Poisson armé.
Key Characters
This species is the only gar in the NCR and is readily identified by the very elongate snout armed with needle-like teeth.
Description
This species is distinguished by the long, narrow snout 14-18 times longer than minimum width, 57-66 lateral line scales and spots only on the body from the pelvic fins to the caudal peduncle and on the dorsal, anal and caudal fins. Gill rakers 14-31. Dorsal fin rays 6-9, anal rays 7-10, pectoral rays 10-13 and 6 pelvic rays. Young fish have dorsal and ventral filaments on the caudal fin. The swimming young fish appears to be moved by a propeller as these filaments vibrate rapidly.
Colour
Adults are grey or olive-brown to dark green fading to pale green or silver on the flanks and white on the belly. Colour is variable with habitat. Flank scales often outlined in black. The dorsal, anal and caudal fins are pale brown to yellow and spotted. Pectoral and pelvic fins are dusky without spots. Young have a narrow reddish-brown or black stripe on the back, and one on the mid-flank which has a wavy upper edge. Above the flank band they are brown to black, below brown with white or cream areas.
Size
Reaches over 2 m and possibly over 22.8 kg. The world, all-tackle angling record weighed 22.82 kg and came from the Trinity River, Texas in 1954, but this may have been another species, probably an Alligator Gar. A gar weighing 16 lbs (7.3 kg) and measuring 40 inches (1.02 m) in length was caught near Rideau Falls in the Ottawa River (Anonymous, 1974b), a 13.9 lbs (6.3 kg) gar from the Ottawa River on 3 July 1973 ( www.canadian-sportfishing.com/NationalFishRegistry/Catch_And_Keep1.asp), a 15.2 lbs (6.9 kg) fish was caught by Scott Thibeault in the Ottawa River on 1 June 2001 (www.ofah.org/Registry/fish.cfm?RecID=23, downloaded 14 May 2004), a 51 inch fish with a 16 inch girth was caught by Jeff Cyr in the Ottawa River on 6 October 1994 ( www.canadian-sportfishing.com/NationalFishRegistry/Live_Release1.asp, downloaded 13 June 2003), and gar about 20 lbs and 54-57 inches long are reported form the Ottawa River (G. Barnardo, in email, 10 June 2004).
Distribution
In Canada found from the St. Lawrence River basin, the Great Lakes, but rare in Lake Superior, across southern Ontario. In the U.S.A. found in the Mississippi River, Great Lakes and southern Atlantic coastal basins, absent from the eastern American mountains. In the NCR it is found in the Ottawa River and mouths of tributary rivers.
Origin
This species entered the NCR from a Mississippian or possibly an Atlantic coastal refugium (Mandrak and Crossman, 1992).
Habitat
It is usually found in quiet, weedy shallows of lakes and larger rivers and, because of its air-breathing ability, enters hot stagnant waters to feed where other predators could not survive. The preferred temperature is said to be 33.1°C. Gars can be seen in summer hovering motionless at the surface although they dive rapidly out of sight if disturbed. They can also be seen at night in summer when canoeing in Shirley's Bay, the most common mid- to large-sized fish in the bay (Eric Snyder, pers comm., 7 January 2008).
Age and Growth
Maximum age is 27 years for males and 32 years for females. Females grow faster and the sex ratio of males to females changes from about 262 to 100 in early life to only 8 males per 100 females after age 10.The growth of young is the fastest of any North American freshwater fish. These gar are mature at 6 years and 50.0 cm.
Food
Food is usually all fishes of suitable size, more rarely frogs, crayfish and even small aquatic mammals. Prey is seized by a sideways slash of the snout after a dart or drift from cover. The prey, impaled on the teeth, is manoeuvred so that is can be swallowed head first.
Reproduction
Spawning occurs in spring and summer at 20°C or warmer usually in weedy shallows. Ripe gar that were presumed to be spawning were caught in the lower Carp River, Fitzroy Harbour Provincial Park on 10 June 1964 (McAllister and Coad, 1975). Water temperature was 23°C and the current medium over a rocky bottom. Gar are also reported as spawning in a large pool in the Ottawa River at the end of Woodroffe Avenue in June (www.ottawariverkeeper.ca/riverkeeper/ecology/@200_river/phen.html) and on 13 June 2008 in the Quyon River at the lower bridge (see below). The female is approached by up to 15 males which she leads in an elliptical path. The males nudge the female's belly area with their snouts while oriented head down. Males and female quiver and eggs and sperm are released. The eggs are scattered and attach to vegetation. The eggs are dark green, perhaps as camouflage, and measure 3.2 mm in diameter. The number of eggs may be as high as 77,156. Eggs are poisonous to birds, mammals and humans, and can kill smaller mammals. In Ontario gar eggs have been found in the nests of Smallmouth Bass and such nests had a higher success rate than nests with only bass eggs. Whether gar are deliberately spawning over bass nests is uncertain, they may merely be in the same area. However they do gain an advantage because the bass defends the nest against predators. Curiously, gar eggs are eaten by other fish despite being reputedly poisonous to mammals. The bass may benefit by having larger gar eggs and larvae in the nest to distract predators from the smaller bass eggs and larvae. Also more eggs and larvae of whatever species lessens the chance of individual loss to a single predatory attempt. Conversely, the male bass has more eggs to guard and the larger gar eggs are more attractive to predators, but on balance both fish species benefit. The young gar have an adhesive pad on the snout tip which attaches them to weeds. After about 9 weeks the yolk-sac is absorbed, the gar no longer hangs vertically from vegetation and is free-swimming. They grow very rapidly, as much as 3.9 mm a day, much faster than most other Canadian freshwater fishes.
Importance
Gar are considered a pest because they eat other fishes and are often killed by fish. They have been pursued in the NCR by anglers who specialise in trying to catch this species with its narrow bony mouth. They are edible, better tasting when smoked, although they are hard to clean because of the bony armour. The flesh must be carefully cleaned of the eggs before eating as these are thought to be poisonous although there is some dispute about this.
© Brian W. Coad (www.briancoad.com)