Fig 3 - available via license: Creative Commons Zero 1.0
Content may be subject to copyright.
Relative total change in predator abundance (A) and fishery performance (B and C) across modeled scenarios and aggregated at the scale of the full model arena. Lighter shades are at 30 years in the model run, and darker shades at 100 years. Fishery performance is measured both as relative catch (B) and the probability of a threshold violation (C). Feedback strategies are indicated in blue, and the MPA in orange. All results are relative to the No FBM or No MPA scenarios, with the dashed grey line at 1.0 indicating no impact of FBM or the MPA. https://doi.org/10.1371/journal.pone.0231954.g003
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
... abundances of krill predators were sensitive to the management strategies investigated here. For results aggregated across the model arena, FBM-Krill caused little change in the total abundances of penguins or seals relative to the No FBM scenario ("small" or no absolute changes, all < ±0.10%), but more obvious declines were projected for both species groups with FBM-Pengs (Fig 3A), with a small decline (-0.04) in penguins and a medium decline (-0.11) in ...
Context 2
... general, we projected only small changes in fishery performance. For the krill fishery, projected catches over the whole model arena were relatively unaffected by the two FBM strategies and the MPA (Fig 3B). FBM-Krill resulted in small or no change (-0.01 and +0.005 for FBM-Krill and -0.01 and +0.03 for FBM-Pengs, for 30 and 100 years, respectively), and the MPA only a small increase that did not change over time (+0.04). ...
Context 3
... resulted in small or no change (-0.01 and +0.005 for FBM-Krill and -0.01 and +0.03 for FBM-Pengs, for 30 and 100 years, respectively), and the MPA only a small increase that did not change over time (+0.04). We found comparatively greater differences between management strategies in terms of the probabilities of threshold violations, with small changes under FBM-Krill (-0.01 across time in the model), slightly larger but still small decrease with FBM-Pengs (-0.03 at 30 years and -0.05 at the end of the model run), and medium increases with the MPA (+0.15 and +0.11) (Fig 3C). ...
Context 4
... strategies that fail to conserve predator populations in the near term seem likely fail over the long term as well, even if these strategies are designed to adjust to future change. Yet our projections with FBM-Krill and the MPA also indicate that management strategies which are successful in the near term may help to mitigate negative outcomes in the long run as well (Figs 3, 4, 6 and 7). ...
Similar publications
Assessing environmental changes in Southern Ocean ecosystems is difficult due to its remoteness and data sparsity. Monitoring marine predators that respond rapidly to environmental variation may enable us to track anthropogenic effects on ecosystems. Yet, many long-term datasets of marine predators are incomplete because they are spatially constrai...
With accelerating climate variability and change, novel approaches are needed to warn managers of changing ecosystem state and to identify appropriate management actions. One strategy is using indicator species—like seabirds as ecosystem sentinels—to monitor changes in marine environments. Here, we explore the utility of western gulls ( Larus occid...
The Atlantic sector of the Southern Ocean (ASSO) has one of the highest densities of Antarctic krill ( Euphausia superba ) compared to other polar and subpolar regions, which attracts migratory baleen whale species to aggregate in this area for feeding. Humpback whales ( Megaptera novaeangliae ) also sing extensively while on the Southern Ocean fee...
The west Antarctic Peninsula is an important breeding and foraging location for marine predators that consume Antarctic Krill (Euphasia superba). It is also an important focus for the commercial fishery for Antarctic krill, managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Aiming to minimise ecosystem ris...
In Antarctica, abundant consumers rely on Antarctic krill for food, but krill are also the subject of a commercial fishery. The fishery overlaps in time and space with the foraging areas of these consumers, thus potential competition between krill fisheries and krill consumers is a major management concern. The fishery is managed by the Commission...
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.
