Abundance estimates and morphometric measurements of Red Snapper larvae collected in the northern Gulf of Mexico

These data were included in analyses of larval red snapper abundance and condition in relation to the Deepwater Horizon oil spill (DWHOS) and environmental conditions within the study region. Ichthyoplankton samples were collected once a month (May through October) along a cross-shelf transect off the coast of Alabama (USA) during years prior (2007–2009) and after (2011, 2013) the DWHOS, and twice a month during the DWHOS (2010). Samples were collected during daylight hours using a Bedford Institute of Oceanography Net Environmental Sampling System (BIONESS; Open Seas Instrumentation, Inc., Musquodoboit Harbour, Nova Scotia, Canada). The BIONESS had a 0.25-m2 mouth opening fitted with 333 μm or 202 μm mesh nets. All Red Snapper larvae used in the morphometric analyses were imaged under a dissecting microscope fitted with a high-resolution digital camera (Canon EOS Rebel T3i, Canon Inc., Tokyo, Japan). Body dimensions were measured using i-Solution Lite imaging software (IMT i-Solution, Inc., Rochester, New York). Web-based and open sources of environmental data used in the analyses are also reported here.