Data from tethering experiment to measure in-situ blue crab mortality as a function of structure

Data collected from field experiment on blue crab tethers in Wassaw Sound, Georgia. Abbreviations of variables are as follows, Site (representing general deployment area): TC= Tybee Creek; SK= Skidaway River; RM = Romerly Marsh); Position: on = on reef; off= off reef; Date: deployment date in field (treated as blocking factor in analysis); CW: Carapace width; CL: Carapace length; Crab Status: A=alive, D=dead; Shark Involved?: P=predation by shark; N=no predation by shark (based on forensics evidence and best guess. All alive crabs were automatically coded as N). To examine the mortality of blue crabs as a function of position (or habitat) , we used a generalized linear mixed effects model to analyze individual crab survival with a binary distribution and a logit link function as influenced by the fixed effect of position (i.e., on reef or off reef). Because the response of crabs within a given deployment batch may not be fully independent, deployment replicate (i.e., date) was used as a random effect.