Estimation of Potential Impacts from Offshore Liquefied Natural Gas Terminals on Red Snapper and Red Drum Fisheries in the Gulf of Mexico: An Alternative Approach

Abstract

As of October 1, 2005, seven offshore liquefied natural gas (LNG) terminals have been proposed to be sited in offshore waters of the Gulf of Mexico. Six of these facilities have opted to use open-rack vaporizers (ORVs) to heat and regasify the LNG and one plans to use a combination open-closed-loop system. Each of the terminals would require on the order of 100-200 million gallons (380-760 × 10⁶ L) of seawater per day to vaporize the LNG. The potential impact on fishery stocks resulting from the entrainment of fish eggs and larvae has emerged as the foremost issue associated with the LNG terminals. The U.S. Coast Guard (USCG) and the Maritime Administration (MARAD) have used forward-projecting equivalent adult models (EAMs) to evaluate the expected levels of impacts from entrainment and have concluded that the effects, while adverse, are minor. The results of these analyses have, however, predicted losses of a magnitude that have been interpreted by resource managers to represent significant reductions in important, overfished stocks of red drum Sciaenops ocellatus and red snapper Lutjanus campechanus. In this paper we show that the forward-projecting EAMs are probably inappropriate and describe a fecundity hindcasting approach that is used in conjunction with the existing stock assessment models to estimate the impacts of entrainment on stocks and yields. The results of these analyses suggest that the effects on red drum yields are 387-fold lower than the impacts on red drum yield estimated by the USCG and MARAD using the forward-projecting EAM. For red snapper the impacts on yield using the fecundity hindcasting approach are 19-fold lower than the effects estimated by the USCG and MARAD using the forward-projecting approach. If our estimates are correct, the proposed LNG terminals will have minor adverse impacts on the subject stocks.