Spatial Distribution Changes and Habitat Use in Red Porgy in Waters off the Southeast U.S. Atlantic Coast

Abstract

AbstractDespite 30 years of relatively strict management measures, the Red Porgy Pagrus pagrus population off the southeast U.S. Atlantic coast has not met rebuilding goals and was still categorized as overfished over a decade after a moratorium (SEDAR 2020). The lack of recovery indicates that limiting fishing pressure is not enough to effectively manage population levels. Population size may be driven by spatial or habitat associations independent of fishing pressure. We defined spatial distribution and habitat associations of Red Porgy adults and recruits by using a 23‐year, fishery‐independent trap catch time series (1996–2019). Abundance of recruits was below the long‐term average, and adults were declining for the last 8 years of the time series. In addition, the spatial distribution of recruits tended to contract to deeper waters in the center of the region when abundance was low, whereas adults remained relatively consistent in their spatial and depth distribution regardless of abundance. The independence between effective area occupied and adult abundance supports that adults persisted throughout the region, whereas recruit area occupied was proportional to abundance. Recruits and adults overlapped spatially, but there was some partitioning of habitats: recruits were more abundant in less‐complex habitats (low benthic biota coverage and low availability of hard substrate) relative to more complex habitats, and adults were more abundant in more complex or warm habitats than in less‐complex or cooler habitats. When overall abundance was reduced, adult abundance in more complex habitats became more similar to abundance in less‐complex habitats, while there was little to no change in recruit habitat use. The center of the region had a high overlap of adults and recruits, particularly in times of reduced recruitment. If fishers cannot target adults only, there is high potential for bycatch mortality or reduced fitness for recruits, which would further reduce the likelihood of recovery.