DOI: 10.5061/dryad.h58n0
title: Data from: Evaluation of Blue Crab, Callinectes sapidus, megalopal settlement and condition during the Deepwater Horizon oil spill

description: The Blue Crab, Callinectes sapidus, is a commercially, culturally, and
 ecologically significant species in the Gulf of Mexico (GOM), whose
 offshore stages were likely impacted by the Deepwater Horizon oil spill
 (DWH). To test for DWH effects and to better understand the planktonic
 ecology of this species, we monitored Callinectes spp. megalopal
 settlement and condition at sites within and outside of the spill extent
 during and one year after the DWH. We tested for DWH effects by comparing
 2010 settlement against baseline data available for two sites, and by
 testing for differences in settlement and condition inside and outside of
 the spill extent. We also developed time series models to better
 understand natural drivers of daily settlement variation (seasonal and
 lunar trends, hydrodynamics, wind) during 2010 and 2011. Overall, we found
 that neither megalopal settlement nor body weight were significantly
 reduced at oiled sites, but that high unexplained variation and low
 statistical power made detection of even large effects unlikely. Time
 series models revealed remarkably consistent and relatively strong
 seasonal and lunar trends within sites (explaining on average 28% and 9%
 of variation, respectively), while wind and hydrodynamic effects were weak
 (1–5% variation explained) and variable among sites. This study provides
 insights into DWH impacts as well as the natural drivers of Callinectes
 spp. megalopal settlement across the northern GOM.
description: Callinectes spp.
 settlement in 2010 and 2011 at various sites in the Gulf of
 MexicoThis data file has 3
 fields. "Site" is the site from which the sample was collected.
 "Date" is the date of collection (note that there were 2-4
 replicates at a site each day). "Callinectes_Meg_N" is the
 number of Callinectes spp. megalopae caught on that replicate collector.
 All megalopae samples were collected using a standard collection method as
 described in the associated manuscript. Exact coordinates (Long/Lat in
 decimal degrees) of the sites were: APALACHICOLA -84.980706, 29.726056,
 RIGOLETS -89.793158, 30.064297, DAUPHIN -88.077806, 30.251275, GALVESTON
 -94.817131, 29.312742, GRAND ISLE -89.962331, 29.262911, OCEAN SPRINGS
 -88.800297, 30.39155, PENSACOLA -87.159075, 30.337825 and RIGOLETS
 -89.634422, 30.152858. All seven sites were sampled in 2010 and in 2011
 only GALVESTON, GRAND ISLE, DAUPHIN, and PENSACOLA were
 sampled.Dryad_dataset.xlsxCallinectes sp. megalopae dry weightsThis data includes the mean dry weights of Callinectes sp. megalopae fixed in ethanol as described in the associciated manuscript. The dataset includes four fields. First is "Year", either 2010 or 2011. The second is "Site", one of 7 sites (see notes on Settlement file for site coordinates). The third field is the biweekly weight period. Period A starts on May 16th, B on May 30th, C on June 13th and so on until October 31st for a total of 12 biweekly periods each year. The "WPU_mg" field is the individual dry weight in milligrams measured for that time period.Dryad_weights.xls