Sustainable Marine Aquaculture

EFFECT OF ENVIRONMENTAL AMMONIA AND NITRITE ON FLORIDA POMPANO EGGS AND LARVAE

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

Florida pompano Trachinotus carolinus are currently being evaluated as a potential candidate for mariculture in the US. Presently, only limited information exists with respect to this species' tolerance to aquaculture toxicants such as ammonia and nitrite and no work to date regarding this topic has been conducted using early developmental stages. To address this issue, experimental trials were conducted to determine the effect of environmental ammonia and nitrite on pompano eggs and larvae.

Trials were conducted using 1.0-L glass jars filled with 500 ml sterilized seawater (temperature = 24 C; salinity = 35.0 g/L; ph = 8.1). In ammonia exposure trials a control (0 mg/L unionized ammonia-nitrogen; UIA-N) and five nominal UIA-N concentrations (0.1, 0.2, 0.4, 0.8, and 1.6 mg/L), achieved via addition of ammonium chloride, existed at four replicates/treatment level. In nitrite exposure trials five nominal nitrite-nitrogen (NO2-N) concentrations (5, 10, 20, 40, and 80 mg/L) were achieved through addition of sodium nitrite. Fertilized eggs and larvae (1 d post-hatch; DPH) were stocked at 100 individuals/jar. Advanced larvae (10 DPH) were stocked at 10 individuals/jar. Percent hatch of eggs and percent larval survival were determined after 24-h exposure.

Results (see table below) indicate that eggs are highly resistant to environmental ammonia, however newly-hatched and advanced larvae are less tolerant. Regarding nitrite, advanced larvae were found to tolerate the highest exposure level tested (egg and newly-hatched larval trials ongoing). Additional results of ongoing trials involving exposure of pre and post-metamorphic larvae (20 and 30 DPH, respectively) to ammonia and nitrite will be presented.