Spatial Patterns in Relative Abundance and Habitat Use of Adult Gray Snapper off the Southeastern Coast of the United States

Abstract

AbstractGray Snapper Lutjanus griseus is an economically and ecologically important species in the estuarine and coastal environments of the southeastern United States. Previous research has focused primarily on juvenile Gray Snapper due to their accessible inshore distribution and ecological importance, while adults, which often occur offshore and are the main focus of fishing pressure, remain poorly understood. Seven years of baited underwater video data (2011–2017; N = 8,379 videos; ~14,000 h of video) were collected along the continental shelf between North Carolina and Florida (~100,000 km2) to better understand the ways in which the relative abundance of Gray Snapper varied by space, time, habitats, and environmental conditions. Adult Gray Snapper were observed on 6.9% of the videos overall, but they were much more commonly observed in Florida (16.9% of the videos) compared with the states that are north of Florida (1.4% of the videos). We used delta‐generalized additive models to determine that adult Gray Snapper primarily occurred in high‐relief hardbottom sites south of St. Augustine, Florida, in warm water less than 50 m deep, after accounting for imperfect detection on video. Temporal variability was relatively minor despite relatively high precision (the mean annual coefficient of variation = 24%). Fifteen large aggregations of Gray Snapper (i.e., >20 individuals counted on a single frame) were observed on video, but it is unclear whether these aggregations indicated potential spawning aggregation sites. This work provides greater insight into the ecology of Gray Snapper during their important coastal‐ocean adult life stage, which will improve their management and conservation.