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![Spatial structure of the ecosystem model. Subareas 48.1, 48.2, and 48.3 are labelled, and within these, smallscale management units (SSMUs; [42]) are also outlined, as well as labeled in red; the modeled MPA is in light blue. https://doi.org/10.1371/journal.pone.0231954.g001](publication/344205455/figure/fig1/AS:987078653378565@1612349298721/Spatial-structure-of-the-ecosystem-model-Subareas-481-482-and-483-are-labelled-and.png)
Spatial structure of the ecosystem model. Subareas 48.1, 48.2, and 48.3 are labelled, and within these, smallscale management units (SSMUs; [42]) are also outlined, as well as labeled in red; the modeled MPA is in light blue. https://doi.org/10.1371/journal.pone.0231954.g001
Source publication
To implement ecosystem-based approaches to fisheries management, decision makers need insight on the potential costs and benefits of the policy options available to them. In the Southern Ocean, two such options for addressing trade-offs between krill-dependent predators and the krill fishery include "feedback management" (FBM) strategies and marine...
Contexts in source publication
Context 1
... et al. [39] with updates in [41,38]), only adjusting for the FBM and the MPA scenarios considered here as described below. Spatially, the model arena covers three of the CCAMLR statistical subareas in the Atlantic Sector of the Southern Ocean, Subareas 48.1, 48.2, and 48.3 (Fig 1). These subareas are further subdivided into the SSMUs to better address the ecosystem impacts of krill fishing by providing a management mechanism to spatially distribute catches [42]. ...
Context 2
... this decision, we computed catch limits as the products of (1) the initial krill biomass across the model arena; (2) the harvest rate that CCAMLR used to establish the current total precautionary catch limit for krill in our study area (0.093); and (3) proportions that distribute the overall catch limit among SSMUs (and see Model Table 1. Species composition of krill predator groups and where they are modeled as resident by small scale management unit (SSMU , Fig 1). ...
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Citations
... almost200 years, fishery studies have focused on the species distributed in the 48 Antarctic Peninsula (Zhu et al., 2020), Weddell (Roche et al., 2019), Ross (Mormede 49 et al., 2020), and Scotia Seas (Collins et al., 2008;Klein and Watters, 2020); however, the Antarctic continental shelf (Collins et al., 2012;Donnelly and Torres, 2008;53 Donnelly et al., 2004;Gon and Heemstra, 1990), has the second-largest fish biomass 54 next to the Antarctic silverfish (Pleuragramma antarctica) in the Cosmonaut Sea and 55 Prydz Bay( Van de Putte et al., 2010). Adult N. coatsorum individuals live from0-4 habitat suitability and future habitat changes of N. coatsorum in the Southern Ocean. ...
The Southern Ocean faces many challenges under global climate change. Species distribution models (SDMs) are considered a powerful tool for predicting the potential distributions of species when evaluating the effects of climate change. We employed a partially area-under-the-curve (AUC)-based ensemble model to predict the current habitat suitability and future habitat changes of N. coatsorum in the Southern Ocean. The SDMs developed included six different predictors that contribute to the N. coatsorum distribution: depth accounted for the highest contribution of 33.8%, closely followed by the sea surface temperature (30.3% contribution). The contributions of the sea surface salinity distance from land, sea ice thickness and current velocity were 12.7%, 12.3%, 8.1%, and 2.8%, respectively. N. coatsorum has a suitable distribution area of approximately 5.63 million km² under current conditions, comprising29.8% of the Southern Ocean area. A significant expected decrease(43.0%) at the species’ northward edges, especially on the southeast Antarctic coast, may occur in the future as suggested by comparing the current model range to the suitable habitat changes predicted in 2100 under the RCP8.5 scenario, resulting in the formation of three newly gained or remaining climate refugia for N. coatsorum: areas close to the Ronne and Filchner Ice Shelves in the Weddell Sea, the Ross Sea, and along the coast of northeastern Antarctica (including in the Cosmonaut Sea and Prydz Bay). Our ensemble approach for assessing the habitat features of N. coatsorum allows the impacts of climate change on a mesopelagic fish species in the Southern Ocean to be assessed.
Global targets for area-based conservation and management must move beyond threshold-based targets alone and must account for the quality of such areas. In the Southern Ocean around Antarctica, a region where key biodiversity faces unprecedented risks from climate change and where there is a growing demand to extract resources, a number of marine areas have been afforded enhanced conservation or management measures through two adopted marine protected areas (MPAs). However, evidence suggests that additional high quality areas could benefit from a proposed network of MPAs. Penguins offer a particular opportunity to identify high quality areas because these birds, as highly visible central-place foragers, are considered indicator species whose populations reflect the state of the surrounding marine environment. We compiled a comprehensive dataset of the location of penguin colonies and their associated abundance estimates in Antarctica. We then estimated the at-sea distribution of birds based on information derived from tracking data and through the application of a modified foraging radius approach with a density decay function to identify some of the most important marine areas for chick-rearing adult penguins throughout waters surrounding Antarctica following the Important Bird and Biodiversity Area (IBA) framework. Additionally, we assessed how marine IBAs overlapped with the currently adopted and proposed network of key management areas (primarily MPAs), and how the krill fishery likely overlapped with marine IBAs over the past five decades. We identified 63 marine IBAs throughout Antarctic waters and found that were the proposed MPAs to be adopted, the permanent conservation of high quality areas for penguin species would increase by between 49 and 100% depending on the species. Furthermore, our data show that, despite a generally contracting range of operation by the krill fishery in Antarctica over the past five decades, a consistently disproportionate amount of krill is being harvested within marine IBAs compared to the total area in which the fishery operates. Our results support the designation of the proposed MPA network and offer additional guidance as to where decision-makers should act before further perturbation occurs in the Antarctic marine ecosystem.
