Ocean pout
Zoarces americanus
FAMILY
Zoarcidae
TAXONOMY
Blennius americanus Bloch and Schneider, 1801, American seas.
OTHER COMMON NAMES
English: Muttonfish, yowler; French: Loquette d'Amérique.
PHYSICAL CHARACTERISTICS
Body eel-like but rather stout in adults. Pectoral fins large and fan-like. Pelvic fins have short splints. The dorsal and anal fins are continuous with the caudal fin; the dorsal fin has about 15–25 tiny spines at its rear. Background color usually muddy yellowish, tinged with brown above and becoming darker with age. Belly usually yellowish but can be olive-green. Mottling on the sides is brown, but the pattern is individually variable. Teeth are green in northern populations owing to predation on sea urchins. Scales are minute, round, and not overlapping.
DISTRIBUTION
Southern Labrador south to Virginia.
HABITAT
Adults found on the outer shelf to about 219 yd (200 m) on sandy or muddy bottoms. Young may come into intertidal areas among seaweed and rocks. Free-swimming hatchlings sometimes found in estuaries of large rivers to the north.
BEHAVIOR
Very little is known of behavioral traits in ocean pout, mostly owing to the difficulty of observing them in their usual offshore habitat. Based on aquarium observations, they probably live passive, solitary lives without territories and seem only to congregate for spawning. Spawning consists of several copulations over many hours. Large spawning males are aggressive to smaller males at this time, as are females with non-spawning females. Parental care of the eggs occurs (see below).
FEEDING ECOLOGY AND DIET
Grazer. Feeds on invertebrates on or within the sea floor, mostly on crustaceans (amphipods, Cancer crabs, and hermit crabs especially), sea urchins, worms, bivalves (clams and scallops), sea snails, and brittle stars. Fish found in a few stomachs occasionally are probably scavenged.
REPRODUCTIVE BIOLOGY
Spawning occurs in early to mid-Autumn and consists of males approaching ripe females and rolling on their sides or even upside down under the female. Fertilization is internal and several copulations occur for 2–3 minutes each over many hours, perhaps up to half a day. Egg laying occurs around 6–17 hours after the last copulation. Large females lay a clutch of eggs in rocky areas more numerous than smaller females. A female at nearly 35.4 in (90 cm), near the maximum size, contained over 4,100 ripe eggs; another at 21.6 in (55 cm), and probably spawning for the first or second time, had 1,300 eggs. The eggs are pale yellow and measure 0.24–0.28 in (6–7 mm) in diameter. Upon laying her egg mass the female fans and wipes her skin over the eggs for around 30 minutes. This coats the mass in an antibiotic mucus. Then the female wraps herself tightly around the mass (now white in color), which helps stick it together into an egg ball. Females remain passive while guarding their eggs except for intermittent swimming in circles while fanning the eggs with their pectoral fins. Incubation lasts for three months, during which females probably do not feed much. Fry hatch in mid-winter, and yolk sac resorption occurs in seconds. Fry have a very short planktonic phase while working their way inshore, where they develop over the first few years of their lives.
CONSERVATION STATUS
Not threatened. Common in nearshore environments as young where predation is probably low. Also common offshore even on the fishing banks off New England and Nova Scotia.
SIGNIFICANCE TO HUMANS
A minor fishery for ocean pout began in Massachusetts in the 1930s, with fish being sold "round" in Boston markets. In 1943, as a war effort, a concerted attempt was made to sell whole fillets, and landings reached almost 4.4 million lb (2 million kg) in 1944. However, ocean pout are afflicted with a microsporidian (Protozoa) parasite that produces unsightly lesions in the flesh. Landings dropped to under 6,100 lb (2,767 kg) by 1948, and the fishery subsequently failed. Attempts to revive the fishery in the 1970s also failed.
