Growth Rates in Gulf of Mexico Red Snapper Following the 2010 Deepwater Horizon Blowout

Red snapper, Lutjanus campechanus, is a long-lived, reef finfish and important both commercially and recreationally to the Gulf of Mexico (GOM) region. Mature individuals between ages 2 and 8 inhabit much of the shallow-water oil infrastructure in the northern GOM, which makes them particularly vulnerable to oil contamination. Consequently, much of their range overlaps the surface oil distribution from the 2010 Deepwater Horizon (DWH) blowout. Previous research on acute oil contamination in juvenile fish has shown significant decreases in weight, growth and condition indices- all factors tied to population productivity. The goal of this study is to understand annual growth rate variation in GOM red snapper before and after 2010 through increment analysis of sagittal otoliths collected via scientific demersal long-line sampling in years 2011-2013. The measured annual growth increments, along with ancillary environmental data, will be treated with an ANCOVA to determine the significance of variation in annual growth rates by year and age. Preliminary results show dominant 2005, 2006 and 2007 year classes with poor post-DWH cohorts and a 10-20% decline in otolith increment width occurring in 2010. Corresponding declines in weight at age are equivalent to a 38% reduction in reproductive output.