Exploring the Effects of the Deepwater Horizon Oil Spill on Diet, Growth, and Condition of Larval Spanish Mackerel in the Northern Gulf of Mexico

Impacts of the Deepwater Horizon oil spill (DHWOS) on fish populations in the northern Gulf of Mexico remain largely unknown. Of special concern are the fate of fish eggs and larvae present in the water column during the event, because these are the most vulnerable life stages. Even small changes in hatching success, larval growth, and survival can drive large fluctuations in their adult populations. Using samples from a long-term (2004-2013) ichthyoplankton survey off the coast of Alabama, we seek to resolve the effects of the DWHOS on larval fishes. We compared the condition, growth, and diet of a representative species, Spanish mackerel (Scomberomorus maculatus), during summer months in years before (2007-2009), during (2010), and after (2011-2013) the event. Initial comparisons of body condition (using morphometrics and dry weights), diet (using gut contents), and growth (using otoliths) show seasonal changes in condition; however there were no differences for larvae collected before during, and after the DWHOS. Our results will fill critical information gaps needed by marine ecologists and fisheries managers to understand and predict the short and long-term effects of the DWHOS on important commercial and recreational fisheries in the northern Gulf of Mexico.