Experimental Design Modification
Sampling will end at four months rather than six months. A subsample of fish will be maintained through six months of age to determine if the fish mature.

Culture Period:120 days for offspring (subsample through 180 days).

Fate of Methyltestosterone in the Pond Environment:
Detection of MT in Pond Soil from a CRSP Site

Effluents and Pollution Research 2B (9ER2B)/Experiment

New Aquaculture Systems/New Species Research 3A (9NS3A)/Study

Note: 9NS3A did not appear as a separate work plan in the Ninth Work Plan.The modification below addresses objective 1 of 9NS3, which is being carried out under a subcontract with the University of Arkansas at Pine Bluff.

Experimental Design Modification
Additional information on nutrition of P. brachypomuswill be obtained via feeding experiments to be performed by Rebecca Lochmann at the University of Arkansas at Pine Bluff. Large juvenile fish are from research facilities in Peru; these were sent in July 2000 and are adapting to local conditions and are on feed. Small trials will be conducted to bracket the dietary requirement of this species for Vitamin C and/or E. Basic information on vitamin requirements in this species is lacking. Both of these vitamins are present at high levels in the natural diets of the species, and both are known to affect reproduction in other fish species. Bracketing the vitamin C and E requirements of large juvenile fish would provide information that would be immediately useful for grow-out diets, and could be used as baseline data for determining requirements of broodstock for these vitamins in the future.