Sustainable Marine Aquaculture

TOLERANCE OF FLORIDA POMPANO AND BLACK SEA BASS JUVENILES TO NITRITE AT VARIOUS SALINITIES

Research Team:
Chuck Weirich (USDA) - Principle Investigator
Ken Riley (HBOI) - Principle Investigator
Dave Cerino (USDA)

Florida pompano Trachinotus carolinus and black sea bass Centropristis striata are among several marine finfish species currently being evaluated for mariculture in the US. Initial research indicates that both of these high-value finfish exhibit several desirable traits including ready acceptance of formulated feeds, rapid growth, and adaptability to various culture systems and environments, including sustainable, enclosed biofilter-based production modules operated at reduced salinities. Compared to open pond and net pen culture systems, biofilter-based production systems offer distinct advantages such as increased environmental control, enhanced biosecurity, and reduced discharge effluent. Notwithstanding these benefits, one problem inherent to biofiltration technologies is the development of elevated concentrations of nitrite-nitrogen (NO2-N), well after the establishment of ammonia-reducing Nitrosomonas populations.

To address this topic, a preliminary 96-h range finding test was conducted for both species using static, aerated 100-L circular polyethylene tanks. In each test tanks were filled with 60-L water adjusted to the desired salinity (pompano = 5, 15, and 25 g/L; black sea bass = 10, 20, and 30 g/L). Temperature was maintained at 28 C via immersion heaters (pompano) or 22 C via ambient air (black sea bass). Eight NO2-N levels (see figure) were achieved through the addition of sodium nitrite. Ten pompano (mean weight = 1.8) or black sea bass (mean weight = 16.4) were stocked per tank and mortalities were assessed every 24 h until test termination.

Results of the initial range finding tests suggest that black sea bass are considerably more resistant to NO2-N than pompano, however, tolerance of both species to this environmental toxin is compromised at reduced salinities. These preliminary values will be used to further refine NO2-N tolerance levels of both species at various salinities via determination of 24, 48, and 96-h LC 50 concentrations.