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

Understanding the life histories of amphidromous fish by integrating otolith‐derived growth reconstructions, post‐larval migrations and reproductive traits

“…The suite of factors underlying temporal variation in migration traits is not fully understood for amphidromous species, but this variation needs to be considered in the management of amphidromous fisheries. Fishing pressure can vary over time owing to constraints on fishing effort through management, behaviour of fishers or environmental conditions, and fishery‐related mortality can be selective regarding important temporal traits such as spawning and migration date (Scharf, Craig, & Smith, ; Tillotson & Quinn, ). The whitebait fishery in New Zealand is controlled by seasonal closures and gear limits, with little understanding or integration of stock structure, spatial and temporal variation in life histories or population dynamics into fisheries management (McDowall, ).…”