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![Historical relationship (1995–2013) of observed Mexican and US Recreational (MexRec) catches and total sandbar shark stock biomass. Points plotted in black represent observations from the years 1995–2007, and red points were observed between the years 2008 and 2013. The superimposed lines demonstrate the alternate simulated relationships between MexRec catches with biomass, where the black line represents the “HiMexRec” implementation scenario while the red line represents the “LoMexRec” implementation scenario. [Colour online.]](publication/359487050/figure/fig3/AS:11431281257205645@1719599195781/Historical-relationship-1995-2013-of-observed-Mexican-and-US-Recreational-MexRec.jpg)
Historical relationship (1995–2013) of observed Mexican and US Recreational (MexRec) catches and total sandbar shark stock biomass. Points plotted in black represent observations from the years 1995–2007, and red points were observed between the years 2008 and 2013. The superimposed lines demonstrate the alternate simulated relationships between MexRec catches with biomass, where the black line represents the “HiMexRec” implementation scenario while the red line represents the “LoMexRec” implementation scenario. [Colour online.]
Source publication
Coastal sharks are challenging to manage in the United States due to their slow life history, limited data availability, history of overexploitation, and competing stakeholder interests. Furthermore, species like the sandbar shark (Carcharhinus plumbeus) are subjected to international exploitation unmanaged by the US. We conducted a management stra...
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Overfishing, habitat degradation, and climate change have caused declines in shark populations throughout the world's oceans. However, in the United States Gulf of Mexico (GoM), populations of several coastal shark species are starting to stabilize following decades of successful regulations and enforcement. The stabilization of coastal shark popul...
Citations
... Both complexes appear to be recovering Peterson, Belcher, et al., 2017;E. Cortés, personal communication) with SCS species generally recovering more quickly than LCS species, but recovery is slow due to low intrinsic rates of population growth (Musick, 1999;Peterson et al., 2022). ...
Understanding spatial ecology and predicting animal movements in response to environmental changes, such as anthropogenic climate change and multidecadal variability, is critical for effective conservation strategies. Niche structuring is key to some coastal shark species and size classes coexisting in the US Atlantic and Gulf of Mexico to limit interspecific and intraspecific interaction. Data from four fishery‐independent bottom longline surveys were used to evaluate the abiotic ecological niches of eight species of small and large coastal sharks. Gaussian mixture models separated length composition data into 14 size categories for ecological niche analysis. Generalized additive mixed effect models were fit and coupled with output from dynamic high‐resolution ocean models to predict suitable abiotic habitats, evaluate potential shifts in distribution, and explore the impacts of large‐scale climatological trends on abiotic habitats from 1994 to 2019. The abiotic niche for small coastal sharks generally tended toward warmer, high salinity, shallow bottom waters close to shore. No overarching niche was found for large coastal sharks, but appreciable ontogenetic differences were seen. Most taxa analyzed exhibited declining annual trends in higher quality habitats, particularly during fall months. The analysis provided evidence of shifts north along the Atlantic, to deeper offshore waters in the Atlantic and Gulf of Mexico, and the potential to redistribute in response to multidecadal climate variability for multiple species. The analytical framework described could aid in developing various spatiotemporal management measures, and results provide insight into the habitat characteristics of several species over broad spatiotemporal ranges and through ontogeny.
... Kaplan et al. 2021). For example, an application of MSE to the sandbar shark highlighted the significant impact that unmanaged, international exploitation may have on the management of US species (Peterson et al. 2022b). Future extensions of desk MSEs within the SEFSC may focus on developing and tuning empirical MPs, how to identify regime shifts or other indicators of nonstationarity, which management approaches would be more likely to be implemented in practice, providing additional guidance on identifying exceptional circumstances, or improving the stock assessment process (9.1-9.3). ...
... • Development of best practices for MSE within the US by the National MSE WG (e.g., Walter et al. 2023) • Sandbar shark MSE (Peterson et al. 2022b) Summary ...
Strategic plan for the use of management strategy evaluation at the NOAA Fisheries Southeast Fisheries Science Center
... Coastal sharks are vulnerable to human activities and challenging to manage over space and time. They especially suffer from overfishing and bycatch which includes both discarded and incidental catch, and from competing stakeholder interests such as those of coastal recreationalists (Peterson et al., 2022). Coastal recreational fishers, for example, compete with sharks over food resources, targeting the same prey fish. ...
... Hence, we are obliged to limit further damage to these already vulnerable species. Moreover, those species and others are subjected to international exploitation unmanaged by developed countries (as a case in point, see the sandbar shark case study from the southeast United States in Peterson et al., 2022). ...
Bycatch of non-target species is a pressing problem for ocean management. It is one of the most concerning issues related to human-wildlife interactions and it affects numerous species including sharks, seabirds, sea turtles, and many critically endangered marine mammals. This paper compares different policy tools for ocean closure management around a unique shark aggregation site in Israel's nearshore coastal waters. We provide a set of recommendations based on an optimal management approach that allows humans to enjoy marine recreational activities such as fishing, while maintaining safe conditions for these apex predators which are vital to the local marine ecosystem. To learn more about recreational fishers' derived benefits, we use a benefit transfer method. Our main conclusion is that dynamic time-area closures offer sustainable and effective management strategies. Since these closures are based on near real-time data, they might successfully preserve specific species in limited areas (i.e., small areas).
... Methot and Wetzel 2013;Methot et al. 2020) to the Sandbar Shark to explore the long-term impacts of varied stock assessment frequency on the status of the stock. The approach employed (modified from Peterson et al. 2022) is based on the Maunder (2014) MSE applied to Pacific Bluefin Tuna Thunnus orientalis. The simulation FIGURE 1. Diagram of the management strategy evaluation process, starting with conditioning of the operating models to observed data, Markov chain-Monte Carlo (MCMC) resampling of conditioned operating models to generate multiple iterations with uniquely applied process error, the cycle of applying a management procedure (comprised of the observation model, estimating model, harvest control rule, and implementation model) to the operating model repeatedly throughout the simulation period and noting that performance metrics are obtained from the operating model. ...
... The LFSR relationship makes a different assumption regarding the density-dependent compensatory mechanism, inherently assuming that offspring survival would decrease at high biomass levels, which is a more appropriate assumption for internally fertilizing species, like sharks (Taylor et al. 2013). The effect of assuming an LFSR instead of a Beverton-Holt (BH) stock-recruitment relationship was found to be reduced stock productivity and higher biomass that supports removal of maximum sustainable yield (B MSY ; Peterson et al. 2022). In addition to (1) the base operating model (OM_Base), alternative operating model configurations included (2) a BH stock-recruitment relationship (OM_BH), (3) high h (OM_Hih), (4) low h (OM_Loh), (5) high R 0 (OM_lnR0), and (6) reduced M with BH stock-recruitment relationship (OM_M_BH; Table 1). ...
... The impact of assessment interim periods varied considerably based on operating model and implementation model, following findings from a similarly structured Sandbar Shark MSE (Peterson et al. 2022). That MSE application focused on the management performance of various configurations of a threshold harvest rate control rule, and we refer to that study for additional information on the effect of the structure of the HCR, more detailed analyses on the impact of each implementation modeling scenario, and factors that impact recovery potential for the stock. ...
Stock assessments are particularly resource-intensive processes. Demand for assessments typically exceeds capacity , stimulating interest in reducing stock assessment frequency for suitable species. Species with slow population growth rates, low economic importance, and low recruitment variability, like coastal sharks in the USA, have been identified as appropriate candidates for long-interim assessment periods. We conducted a Stock Synthesis-based management strategy evaluation with a threshold harvest rate control rule within the southeastern USA to assess the impact of stock assessment frequency for the slow-growing Sandbar Shark Carcharhinus plumbeus. Stock assessments for the Sandbar Shark in the southeastern USA have been conducted or updated every 4-6 years since 1998. The Sandbar Shark proved to be a particularly good candidate species for reduced assessment frequency, as noted by unaffected management procedure performance across interim periods of 1, 5, and 10 years. Management objectives, including probability of stock recovery, relative biomass level, cumulative U.S. commercial catch, and probability of overfishing, were minimally adversely impacted with interim periods equal to 15 years. Based on our findings, assessment frequency for large coastal shark species could reasonably be reduced in the future to once every 10 or more years without compromising management success.
