Sea Bass Aquaculture By: Eric Brown

What species are used? European seabass (Dicentrarchus labrax) Sometimes marketed as Mediterranean Sea Bass. Black Sea Bass (Centropristis striata) Spotted Sea Bass (Lateolabrax japonicus)

Reproduction

Seabass Life Cycle Spawn in groups External fertilization Eggs pelagic 2-4 year Sexual maturity Longer in Atlantic Ocean Spawn once a year Embryos develop in 3 days Larval development occurs in about 40 days Protandrous except for European (dioecious) Males in between 4-7 years and females 5-8. Spawning happens in the winter but can happen in the spring in southern areas.

Reproduction in Captivity

Feeding Open Water Eggs feed on yolk Juveniles feed on Zoobenthos (worms, crustaceans, polycheates Adults – neckton (finfish & bony fish) Aquaculture Larva – only feed on small live food (Enriched Rotifers and artemia) Adults – pellet feed (55% protein, 10% lipid) FCR – 1.7:1

Production methods used Cages (new) Lagoon Systems Intensive Semi-intensive Hatcheries Broodstock Spawning

Lagoon Systems Semi-Intensive Extensive Fisherman collect fry from coastal waters May- June Transport with oxygenated tanks to special ponds Extensive February - May Barriers – reeds,nets, cement Nomally polycultured with seabream, mullets, and eels

Hatcheries Broodstock Spawning Breeders of different ages are maintained here Parent can be farm raised or wild Females 5-8years, Males 2-4 years Induce ovulation by hormone treatments Fertilization in spawning tanks and incubation in open water Spawning Move selected breeders to spawning tanks Male:Female – 2:1 Only Females with oocytes in the late-vitellogenic stage (diameter larger than 650 micrometers) selected

Cages Made of steel 4-10m² Nets suspended 6- 8m deep Some anchored on land others in open waters Frequent net changes (15-20 days) Weekly cleaning to remove foul organisms Done by divers

Water Quality pH – between 6-8 Temperature – 20- 22 degrees Celsius Salinity – 27- 29 g/L DO – 7.5 ppm High rates of algae

Economic Importance Overfishing is a large concern and aquaculture of this species has been deemed sustainable Market price in U.S. $6.99 lb Annual Production 60,000 tons Turkey, Croatia, Spain, Italy, Greece

Advantages Disadvantages Very hardy fish Cutting back on Overfishing Easily marketed Could be inexpensive if lagoon aquacultured Long to mature Very competitive market Low filet yield Carnivorous No synthetic larval feed