Fine-Scale Spatial and Temporal Variation in Fishing Mortality of Southern Flounder: Management Implications for a Dynamic Estuarine Fishery

Abstract

Fish demography and the behavior of fishing fleets can vary across fine spatial and temporal scales, generating dynamic patterns of harvest that can impact both fishery yield and the conservation of stock biomass. We conducted a paired tag return experiment in spatially distinct estuarine fisheries during two consecutive years to examine temporal and spatial variation in harvest of a commercially exploited flatfish, the Southern Flounder Paralichthys lethostigma, in North Carolina. Monthly rates of instantaneous fishing mortality (F) varied across the fishing season in different ways, thus generating differences in total F between the two systems despite the fact that the fishery was concentrated in the warmer months and was dominated by the same gear in both systems. Recent patterns in fishing effort among gears and water bodies throughout the state illustrated seasonal and spatial variation that was produced mainly by gear type. Although current regulations in the Southern Flounder fishery recognize the existence of spatial differences in fishery selectivity and seasonality across North Carolina, fleet behavior has shown rapid and dynamic changes over time. When combined with recently documented fine-scale spatial variation in life history traits, these spatial patterns of effort and harvest that change in response to regulatory measures and socioeconomic drivers can potentially influence—in ways that are difficult to predict—the ability of managers to achieve harvest and conservation goals.

Received March 17, 2017; accepted June 20, 2017 Published online August 22, 2017

ACKNOWLEDGMENTS

Funding for this project was provided by grants from the North Carolina Sea Grant Fishery Resource Grant Program. We thank the fishers who participated in this study by aiding in the capture and tagging of Southern Flounder, and we appreciate all individuals who reported the recaptured tags. The NCDMF, the Center for Marine Science and Technology at North Carolina State University, and the University of North Carolina Wilmington provided logistical support. We thank two anonymous reviewers for several comments that helped us to clarify the presentation of our ideas. The findings and conclusions in this paper are those of the author(s) and do not necessarily represent the views of the National Oceanic and Atmospheric Administration or any of its subagencies.