ZEBRA SEA BREAM DIPLODUS CERVINUS A NEW SPECIES IN AQUACULTURE SUITABLE FOR RESTOCKING

Miguel Neves dos Santos*, Pedro Gil Lino, Pedro Pousão-Ferreira and Carlos Costa Monteiro Instituto Nacional de Investigação Agrária e das Pescas (INIAP/IPIMAR) Centro Regional de Investigação Pesqueira do Sul (CRIPSul) Av. 5 de Outubro s/n 8700-305 Olhão, Portugal [email protected]

The zebra sea bream (Diplodus cervinus) is a demersal species living on rocky bottoms with high commercial value in the Algarve. In 2004, we began a marine ranching pilot project using reared juveniles off the Algarve coast (Southern Portugal). Here, we report some preliminary results regarding the potential for restocking zebra sea bream.

The data available on the production of this species indicates that the standard techniques used for other Sparidae can be applied. However, it appears that the growth rates (at least at the larval and post-larval stages) of D. cervinus are higher when compared to other species of Diplodus also produced at the IPIMAR’s aquaculture station. Also, fewer fish have skeletal deformations during production than in other species of the same genus.

About 5,182 juveniles of different sizes were tagged (tag model FD94 T Anchor-Bar, FLOY TAG & Mfg, INC) and released during the summer and autumn, 2004 and 2005. Fish were released near hard artificial substrates (artificial reefs and a breakwater). One hundred and fifty fish were recovered, or 3% of those released. Recreational fishing contributed the most recaptures (>95%). The number of days at liberty ranged from 1 to 284, while the distance traveled ranged from 0 to 21.5 nautical miles. A behavioral deficit of the reared sea breams in the use of refugia and food was observed for a short period following release. However, the gut contents of returned fish shows that the reared specimen were able to search for food and feed on the available prey. The gut contents are dominated by algal remains and predominantly amphipods which is the normal diet for the wild specimens. The species showed growth rates at sea up to >0.5 g/day, but also weight loss (up to 20%) within the first month after release.

Although these are preliminary results and, to our knowledge, the first using Diplodus cervinus, it is worthy to note the potential of this species for local stock enhancement within an integrated coastal management plan for the local small scale fishery.