chapter  Chapter 7
17 Pages

The Effects of Modeled Dispersed and Undispersed Hypothetical Oil Spills on Red Snapper, Lutjanus campechanus, Stocks in the Gulf of Mexico

WithBenny J. Gallaway, Wolfgang J. Konkel, John G. Cole

The present study evaluated the effects of a large, hypothetical oil spill on Red Snapper, Lutjanus campechanus, stocks in the western Gulf of Mexico. Three response actions (no dispersants used, 70% of the spilled oil dispersed, and 100% of the spilled oil dispersed) were modeled, with the SIMAP™ model to determine the volume of water in which total dissolved polycyclic aromatic hydrocarbons (TPAH) 124concentrations exceeded 1 or 50 μg/L for a 1 h period during the spill. We conservatively assumed that these values caused 100% mortality to fish eggs and larvae after only 1 h of exposure. Red Snapper egg and larval densities for the selected spill zone were calculated from the National Marine Fisheries Service’s Southeast Area Monitoring and Assessment Program (SEAMAP) data and multiplied by the volume associated with the 1 or 50 μg/L toxic levels. These estimated losses were compared with the egg standing stock size as reported in recent stock assessments and the number of females required to produce this number of eggs. The estimated egg stock reductions from the total volumes at these toxic TPAH levels were far lower than the reductions that would have to occur for the losses not to be compensated for, based on the steepness and other stock/recruitment attributes assigned to Red Snapper in the stock assessments. The present study indicated little to no effect from the hypothetical oil spill on the Gulf of Mexico Red Snapper population.