NMFS NUMBER: 95-AKR-021
Broodstock Selection and Hatchery Development of Purple-Hinged
Rock Scallops (Crassodoma gigantea) for Marine
February 4, 2001
National Marine Fisheries Service, Alaska Region, P.O.
Box 21668, Juneau, AK 99802-1668. TELEPHONE:
acquisition and transport permits, 80 adult rock scallops
were collected by scuba divers at a southeastern Alaska
site, 500 miles from the Qutekcak Shellfish Hatchery.
The first 30 scallops were sacrificed for analysis by
the Alaska Department of Fish and Game Pathology laboratory
and revealed no organisms of transport significance. The
hatchery was permitted a maximum of 50 adults for broodstock.
Broodstock were spawned and reconditioned regularly throughout
the year. Conditioning and larval rearing methods evolved
and are described in detail in the final report for this
project. Initially, poor larval growth and survival required
development of an appropriate diet for larvae and broodstock.
Four species of microalgaeTahitian Isochrysis
galbana (tIso), Chaetoceros calcitrans (Ccal),
Pavlova lutheri (Pl), and Chroomonas salina
(Chsa) were fed at specific cell ratios and increasing
density. This diet provided (1) the essential PUFA 22:6n3
at a 22:6n3/20:5n3 ratio greater than two and some 20:4n6;
(2) the three sterols: cholesterol, stigmasterol, and
-sitosterol; and (3) carbohydrates for incorporation in
the gametes. Rock scallop larvae grow about three microns/day
at 14 C with about 25 percent survival to the eyed pediveliger
stage. The project period ended before adequate development
of setting and spat rearing methods were complete.