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Atlantic Sturgeon fish identification, its habitats, characteristics, fishing methods.
The Atlantic sturgeon is a long-lived, estuarine dependent, anadromous fish, which can reach 60 years of age, 14 feet (4.3 m) in length and over 800 lbs (370 kg) in weight, but they typically grow to be 6 to 8 feet and no more than 300 pounds. This is among one of the oldest fish species in the world; they have been here on earth since the Cretaceous period more than 120 million years ago The species name of Atlantic sturgeon “oxyrhinchus” means "sharp snout". They are bluish-black or olive brown dorsally on their back with paler sides and a white belly. They have five major rows of dermal scutes instead of true scales. The species is also known for its occasional “leaping” behavior, during which the fish will emerge completely out of the water in a forceful motion.
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The Atlantic sturgeon (Acipenser oxyrinchus) is a member of the Acipenseridae family. Its range extends from New Brunswick, Canada to the eastern coast of Florida in Western Atlantic, Baltic Sea in Europe. They occur occasionally in Bermuda and French Guiana, Northern Gulf of Mexico, Great Britain and North Sea in Elbe drainage. Landlocked populations are in Lakes Ladoga and Onega in Russia.
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Description
The Atlantic sturgeon is elongate fish, pentagonal in cross section with shark-like fins and sharply long V-shaped snout, longer than other sturgeons. There are 2 pairs of short, slender barbels in transverse line midway between end of snout and anterior edge of mouth. They have double row of pre anal shields. Their bony shields are oval. Carina on dorsal shields does not have a conspicuous hook. Rather than having true scales, the Atlantic sturgeon has five rows of bony plates known as scutes.
Distinguish Characteristics
- There are no dorsal spines
- Dorsal soft fin rays: 30–46
- There are no anal spines
- Anal soft fin rays: 22–32
- 7-16 dorsal scutes
- 24-35 lateral scutes
- 6-14 ventral scutes
- Max length: 14 ft (430 cm)
- Max weight: 811 lbs (368 kg)
- Max age: 60 years
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Head and back are bluish-black or olive green and lower surface whitish in color. Viscera are pale.
Atlantic sturgeon are similar in appearance to shortnose sturgeon (Acipenser brevirostrum), but can be distinguished by their larger size, smaller mouth, different snout shape, and scutes.
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Habitats
Atlantic sturgeon inhabits shallow waters of continental shelf. Mainly they forage in brackish waters. At the sea, it occurs in coastal and estuarine areas when not spawning, generally in shallow 33-165 ft (10-50 m) depth nearshore areas on soft bottom dominated by gravel and sand substrates. In freshwaters, it is found in estuaries and large rivers. Adults are highly migratory while at sea, ascends coastal rivers to spawn for a long distance.
Atlantic sturgeons are benthic feeders and typically forage on benthic invertebrates, like crustaceans, worms, mollusks, insect larvae. Sturgeons are bottom-feeders. Their mouth is located on the underside of their head and together with barbels it make the sturgeon well designed for sensing and capturing benthic prey.
Spawning
Atlantic sturgeons are slow-growing and late maturing anadromous fish that migrate from the ocean into the coastal estuaries and rivers to spawn. Males mature in 5-20 years years old when they are approximately 4-5 feet and 90 pounds while females mature in 7-30 years at 6 feet and 160 pounds. Females spawn only once in a 2-6 year period. Mature females may remain in the estuary for 4 to 6 weeks prior to the spawning run, that starting in the spring when temperatures reach approximately 64°F (13-22°C), in February-March in the south, April-May in the mid-Atlantic, and May-June in Canadian waters, it may also occur in the fall in some areas, but actual spawning may not occur until July. Exact time of spawning depends on temperature.
Fecundity of female is associated with age and body size and could range from 800,000 to 4 million eggs in a single year (approximately 20,000 to 30,000 eggs per kg of body weight). Females release eggs during spawning over a rubble bottom in moderately flowing water (46-76 cm/s) between the salt front and fall line of large rivers, more than 10 feet deep. No nest is built, but the highly adhesive eggs stick to rocks or logs on the bottom. Once larvae begin migrating downstream they use benthic structure (mainly gravel matrices) as refuges. Eggs are black, large, measuring 2.55 mm in diameter and hatching in a 5-6 days to 1 week after spawning at 64°F (16-19°C). After hatch it is 9-11mm in length, and exogenous feeding begins after 6-10 days.
No parental care is given the eggs or young. After spawning females normally exit the rivers within 4 to 6 weeks and males may remain in the river or lower estuary until the fall when they forced to return downstream by the increasingly cold water. Juveniles move downstream and inhabit fresh or brackish waters near the river mouth where may remain until 3-5 years of age or about 30 to 36 inches (76-92 cm) long before moving out to near shore coastal and continental waters where they grow and mature.
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Used smoked and fresh. Its meat was delicious, especially when smoked, and Europeans considered its roe or eggs, which can be processed to make caviar, a delicacy.
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