Evaluating the effectiveness of a large multi‐use MPA in protecting Key Biodiversity Areas for marine predators

Abstract

Aim: Marine protected areas can serve to regulate harvesting and conserve biodiversity. Within large multi-use MPAs, it is often unclear to what degree critical sites of biodiversity are afforded protection against commercial activities. Addressing this issue is a prerequisite if we are to appropriately assess sites against conservation targets.We evaluated whether the management regime of a large MPA conserved sites (Key Biodiversity Areas, KBAs) supporting the global persistence of top marine predators.Location: Southwest Atlantic Ocean. Method:We collated population and tracking data (1,418 tracks) from 14 marine predator species (Procellariiformes, Sphenisciformes, Pinnipedia) that breed at South Georgia and the South Sandwich Islands, and identified hotspots for their conservation under the recently developed KBA framework. We then evaluated the spatiotemporal overlap of these sites and the different management regimes of krill, demersal longline and pelagic trawl fisheries operating within a large MPA, which was created with the intention to protect marine predator species. Results:We identified 12 new global marine KBAs that are important for this community of top predators, both within and beyond the focal MPA. Only three species consistently used marine areas at a time when a potentially higher-risk fishery was allowed to operate in that area, while other interactions between fisheries and our target species were mostly precluded by MPA management plans. Main conclusions:We show that current fishery management measures within the MPA contribute to protecting top predators considered in this study and that resource harvesting within the MPA does not pose a major threat-under current climate conditions. Unregulated fisheries beyond the MPA, however, pose a likely threat to identified KBAs. Our approach demonstrates the utility of the KBA guidelines and multispecies tracking data to assess the contributing role of well-designed MPAs in achieving local and internationally agreed conservation targets.

Changes in prey fields increase the potential for spatial overlap between gentoo penguins and a krill fishery within a marine protected area

“…The closure of the krill fishery during summer is an important management measure for reducing spatiotemporal overlap with migratory predator species that disperse away from the maritime zone during winter (GSGSSI, 2013; Handley et al., 2020; Ratcliffe et al., 2015). However, our study confirmed previous observations that gentoo penguins remain in the shelf waters that adjoin their breeding localities throughout the winter (Clausen & Putz, 2003; Hinke et al., 2017; Tanton et al., 2004).…”

“…In 2001, 96% and 100% of gentoo penguin locations were within 10 and 17 km of shore, respectively (Tanton et al., 2004), which led to the conclusion that NTZ1 would prevent overlaps of their foraging distribution with the krill fishery during winter (Handley et al., 2020). Williams et al.…”

“…Antarctic krill Euphausia superba is an important forage species in the South Georgia food web that exhibits pronounced environmentally induced fluctuations in biomass though time (Fielding et al., 2014). South Georgia hosts globally important populations of seabirds (Handley et al., 2020), and variability in the krill stock has strong effects upon the diets, breeding success and population trends of several species (Reid et al., 2005). A fishery within South Georgia's maritime zone operates over the shelf during winter (Grant et al., 2013) and is managed by the Government of South Georgia and the South Sandwich Islands (GSGSSI) within the framework of regulations set by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).…”

“…GSGSSI designated the entire 200 NM maritime zone around South Georgia as a sustainable‐use MPA in 2012, and minimizing competition between predators and fisheries is among the key management considerations (GSGSSI, 2013; Handley et al., 2020). The original MPA regulations included a no‐take zone (NTZ) extending 12 NM (22.2 km; hereafter NTZ1) from shore to segregate fishing and nearshore predator aggregations, and an open season for the krill fishery between 1 April to 31 October when most predator species disperse away from the maritime zone (GSGSSI, 2013; Handley et al., 2020; Ratcliffe et al., 2015). These limits were revised in May 2019 following the five‐yearly MPA review process: the open season was shortened by two months (1 May to 30 September) and the NTZ was extended to 30 km (16.2 NM; hereafter NTZ2), the latter in response to the preliminary findings of this study.…”

“…As residents, gentoo penguins share the South Georgia shelf with the krill fishery during winter, but NTZ1 was believed to prevent their spatial overlap (Handley et al., 2020) based on limited tracking data from a single year that showed birds remain within 17 km of shore (Tanton et al., 2004). However, breeding macaroni penguins Eudyptes chrysolophus at South Georgia extend their foraging ranges when krill is scarce (Horswill et al., 2017).…”