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Lake Sturgeon |
Scientific:
Acipenser fulvescens Rafinesque Description:
Adult Length 1000-2000 mm (40-80 in), Immature Size: 21-1000 mm (8.4 –
40 in). Brown to grey on back
and sides, white underside. 30-40 bony plates on each side, 10-20 bony
plates on back, 5-15 bony plates on each underside. No scales, but very
tough skin. 4 short barbells (whiskers) in front of a sucker-like
downward protruding mouth. Juveniles are similar but snout appears
longer and more pointed; bony plates much sharper, black blotches on
head and body. Fry:
8mm. Similar to
juveniles. Eggs:
3.5mm. Eggs are round and black in colour. Habitat:
Locally in Lake Nipissing, French and Ottawa Rivers. Fry remain in spaces
between rocks from 2 weeks post hatch. Fry are then transported
downstream by current. Juveniles spend early years in shallow waters at
river mouths/deltas. Larger juveniles and adults live in deeper water
(>5m). Spawning
Habitat: Shallow sections of
fast-flowing rivers in rapids or under waterfalls. May also take place
on windswept shoals in lakes. Life History: Eggs are laid mid-May to mid-June (water temperatures 13-18°C) in fast-flowing waters. Eggs adhere to rocks and incubate for 5 days. Fry hatch and remain between rocks in current for a further 10-20 days, until the large yolk sack is digested. Fry then drift downstream by the current and come to rest at shallow river mouths or deltas, remaining for 3-5 years. Fish migrate to deeper,
cooler waters until reaching sexual maturity at age 15-20 for males and
20-25 for females. Males migrate upstream in the spring before females,
and congregate on spawning areas. Females are ripe for a short period of
time, migrate upstream, spawn and migrate downstream quickly. Males
spawn once every 3 years, and females once every 5 years. Lake Sturgeon
is very long-lived; the oldest fish from Lake Nipissing estimated at 97
years old. The largest recorded from Lake Nipissing was 2m.
Similar
Species: None in the area. Ecological
Role: Control abundance of benthic organisms (insects, molluscs,
etc.) through consumption. Threats:
Spawning habitat loss due to dam construction, and alteration of
flows during spawning. Over-fishing,
both commercial and recreational fishing for Lake Sturgeon in Lake
Nipissing is not permitted. What
you can do: Report to
the Natural Heritage Information Centre: http://nhic.mnr.gov.on.ca/nhic_.cfm.
Compiled
by: Scott Kaufman OMNR.
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