P.G. Lee, L. Walsh, and P.E. Turk Cephalopod molluscs are among the most successful taxonomic classes in the animal kingdom. In terms of biomass, fisheries scientists have estimated that there are nearly equal populations of cephalopods and fishes in the world's oceans. Cephalopods have significant commercial importance since they are eaten regularly in many regions of the world, especially the Orient and Southern Europe and they have been used extensively as biomedical research models. To date no commercial culture projects have been initiated, but limited stocking programs have been investigated in Japan and Thailand. Attempts to culture squids during the last 50 years have achieved limited success due to the organisms small hatching size, unknown dietary habits, constant swimming, and susceptibility to skin damage, resulting from captivity. The broad fin squid's (Sepioteuthis lessoniana) egg strands were collected initially from rock and seagrass substrates in mainland Japan, Okinawa or Thailand and were shipped in plastic bags secured in polystyrene boxes with equal parts fresh filtered sea water and gaseous O2. Subsequent generations (6) were spawned in the laboratory. Eggs were incubated in 1.8-m circular hatchery tanks containing natural sea water. These tanks were equipped with a screened central core where the water was withdrawn by gravity or airlift pumps to the filtration tank. The water first passed through a particle filter, a protein skimmer, an activated carbon filter and then the submerged oyster shell biofilter. Filtered water was taken from below the biofilter and flowed back to the hatchery tank through ultraviolet sterilizers. Juvenile squids were moved from the hatchery tanks to either a production raceway (6.1L x 2.4W x 0.9D m, 15,000 L or 9.2L x 4W x 1.2D m, 44,000 L natural or artificial sea water) or a circular production tank (6.5 m diameter x 1.75 m deep, 50,000 L natural or artificial sea water). The filtration systems for the production tanks were similar to those used in the hatchery tanks and airlift pumps maintained all circulation. Estuarine-collected and hatchery reared crustaceans and fishes (e.g. mysid shrimp, grass shrimp larvae and finfish fry) were the primary food organisms during the first 60 d; larger shrimps and fishes were included as the squid grew. Several engineering factors contributed to the culture success: (1) physical design (i.e. size, shape, and painted pattern) of the culture tanks; (2) patterns of water flow in the culture tanks; (3) water filtration systems (especially automated control and denitrification); and (4) spawning substrates. The noteworthy biological characteristics of S. lessoniana are (1) this species is behaviorally and morphological well suited to the laboratory environment; (2) the life cycle is completed in 4-6 months; (3) growth is rapid (>15% wet body weight/d), with adult size from 0.4-2.2 kg; (4) feeding rates are high (30% wet body weight/d) and a variety of live crustaceans and fishes are eaten; (5) crowding is tolerated (>>5 squid/m^3); (6) the incidence of diseases and cannibalism is low; and (7) reproduction in captivity allows culture through six successive generations. Initial production (a few hundred/yr) suggests that large-scale culture will be able to supply the needs of the biomedical research community and portends the eventual large-scale culture of cephalopods for human consumption, especially in the Far East and southern Europe.
(National Resource Center for Cephalopods, Marine Biomedical Institute, University of Texas Medical Branch, Galveston, TX 77555-1163, USA)