ARTIFICIAL REPRODUCTION, TRANSPORT, SPAWN INCUBATION, AND HATCH BREEDING OF ATLANTIC STURGEON ACIPENSER OXYRHYNCHUS OXYRHYNCHUS MITCHILL

Ryszard Kolman, Grzegorz Wiszniewski

Zakład Ichtiologii IRS w Olsztynie

ABSTRACT. Within the framework of research on Baltic sturgeon restitution, 80,000 fertilized spawn was flown in from Canada in July 2008. The spawn was used as the initial research material. At the first stage, the spawn was incubated on special frames places in rectangular tanks with a constant supply of fresh water at a temperature between 18-18.5^oC and oxygen saturation of about 7mg per liter and higher. On the fifth day after fertilization, the first hatch were observed, while incubation was complete two days later. In this period, the survival rate of spawn was very high at 92%. A similar high level of 91.2% was maintained at a fry survival rate at the stage from the end of incubation to the beginning of independent feeding. The first feed of the sturgeon hatch consisted of nauplius of brine shrimp (Artemia sp.) that was delivered ad libitum. Before incubation, the brine shrimp cysts were rinsed in a sodium hypochlorite solution. Decapsulation increased the percentage of Artemia sp. larva hatch out and reduced the incubation time. Additionally, from the beginning of hatch out small doses of Perla pro larvae 6.0 starter were added. The growth rate of the hatch and fry was marked on a lower level in comparison to earlier breeding. On day 55 after hatch out, the average fish weight was 212 mg per fish. The reason for the low growth rate was the low water temperature that was essential for other scientific observations. Parasitological tests were performed during the breeding of Atlantic sturgeon fry. Thanks to which, the trematode Dactylogyrus was found on fish gills. A 1% saline solution, which is safe for the fish, was used to reduce Dactylogyrus.

Key words: sturgeon, incubation, breeding, artificial reproduction, hatch