Condition of larval Spanish mackerel Scomberomorus maculatus in relation to the Deepwater Horizon oil spill

The Deepwater Horizon oil spill (DWHOS) coincided with the pelagic larval stages of many valued commercial and recreational fishes in the northern Gulf of Mexico. Larval fish survival and eventual recruitment into adult populations may have been impacted directly through toxicity or indirectly through changes in the planktonic food web caused by the release of oil and chemical dispersants during the DWHOS event. Using samples from a long-term ichthyoplankton survey off the coast of Alabama, USA, in a region impacted by the DWHOS, the abundance and condition of larval Spanish mackerel Scomberomorus maculatus were compared during summer months in years before (2007-2009), during (2010) and after (2011) the DWHOS. Changes in larval quality were examined using morphometric and weight-based body condition indices, whereas potential trophic impacts were quantified using stable C and N isotopes. Larval abundance did not differ across years. However, larvae were in better body condition during the DWHOS period relative to before the spill. Larvae had generally similar isotopic values through time. Thus, larval Spanish mackerel body condition was largely resilient to the harmful effects of the DWHOS. Responses to the DWHOS are likely taxon-specific, as the resiliency of larval Spanish mackerel starkly contrast the response of another managed species (red snapper) during the same period.