Footprints of fixed‐gear fisheries in relation to rising whale entanglements on the U.S. West Coast

Feist, Blake E.; Samhouri, Jameal F.; Forney, Karin A.; Saez, Lauren E.

doi:10.1111/fme.12478

Cited by 22 publications

(15 citation statements)

References 49 publications

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“…We generated 5 km resolution gridded maps for both the acoustic-trawl and eDNA models to enable direct comparisons between models. This vector-based grid was developed and used by others [34] for interpolating various spatial models and uses a custom coordinate reference system that conserves area and distance reasonably well across the west coast of the USA (electronic supplementary material) and was a suitable resolution for the purposes of our analyses.…”

Section: Introductionmentioning

confidence: 99%

Environmental DNA provides quantitative estimates of Pacific hake abundance and distribution in the open ocean

et al. 2022

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All species inevitably leave genetic traces in their environments, and the resulting environmental DNA (eDNA) reflects the species present in a given habitat. It remains unclear whether eDNA signals can provide quantitative metrics of abundance on which human livelihoods or conservation successes depend. Here, we report the results of a large eDNA ocean survey (spanning 86 000 km 2 to depths of 500 m) to understand the abundance and distribution of Pacific hake ( Merluccius productus ), the target of the largest finfish fishery along the west coast of the USA. We sampled eDNA in parallel with a traditional acoustic-trawl survey to assess the value of eDNA surveys at a scale relevant to fisheries management. Despite local differences, the two methods yield comparable information about the broad-scale spatial distribution and abundance. Furthermore, we find depth and spatial patterns of eDNA closely correspond to acoustic-trawl estimates for hake. We demonstrate the power and efficacy of eDNA sampling for estimating abundance and distribution and move the analysis eDNA data beyond sample-to-sample comparisons to management relevant scales. We posit that eDNA methods are capable of providing general quantitative applications that will prove especially valuable in data- or resource-limited contexts.

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Section: Introductionmentioning

confidence: 99%

Environmental DNA provides quantitative estimates of Pacific hake abundance and distribution in the open ocean

et al. 2022

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“…We constructed an index of risk of entanglement in Dungeness crab fishing gear for blue and humpback whales based on overlap of whale and fishing distributions. We derived predicted whale distributions from habitat suitability and habitat-based density models [ 18 , 41 ] and fishing distributions and revenues from vessel monitoring system (VMS) data linked to California landings receipts registering Dungeness crab [ 42 ]. The VMS data contained approximately 370 000 geolocations of greater than 280 crab vessels, which we matched to greater than 16 000 landings receipts (fishing trips).…”

Section: Methodsmentioning

confidence: 99%

Marine heatwave challenges solutions to human–wildlife conflict

et al. 2021

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Despite the increasing frequency and magnitude of extreme climate events, little is known about how their impacts flow through social and ecological systems or whether management actions can dampen deleterious effects. We examined how the record 2014–2016 Northeast Pacific marine heatwave influenced trade-offs in managing conflict between conservation goals and human activities using a case study on large whale entanglements in the U.S. west coast's most lucrative fishery (the Dungeness crab fishery). We showed that this extreme climate event diminished the power of multiple management strategies to resolve trade-offs between entanglement risk and fishery revenue, transforming near win–win to clear win–lose outcomes (for whales and fishers, respectively). While some actions were more cost-effective than others, there was no silver-bullet strategy to reduce the severity of these trade-offs. Our study highlights how extreme climate events can exacerbate human–wildlife conflict, and emphasizes the need for innovative management and policy interventions that provide ecologically and socially sustainable solutions in an era of rapid environmental change.

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“…Southeast Farallon Island is one of the largest seabird breeding colonies in the Eastern Pacific and has the largest breeding population of western gulls in California (Ainley, 1990). In addition to this region containing important seabird habitat, the San Francisco Bay area contains a large port with high shipping and fishing traffic, high humpback whale density, and is a hotspot for the commercial Dungeness crab (Metacarcinus magister) fishery-the largest fixed-gear fishery in central California (Feist et al, 2021).…”

Section: Western Gull Tracking and Data Processingmentioning

confidence: 99%

“…A particularly concerning issue in the California Current system is severe whale injury or mortality as a result of entanglements in fishing gear and ship strikes (Williams and O'Hara, 2010;Redfern et al, 2013;Rockwood et al, 2021). With the urgent need to utilize ecosystem data to advise marine resource management, working groups were established to develop mitigation strategies and understand drivers of increased whale entanglement (Santora et al, 2020;Feist et al, 2021;Ingman et al, 2021) and ship strikes (Hazen et al, 2017;Abrahms et al, 2019;Blondin et al, 2020;Rockwood et al, 2020). Specifically, humpback whales (Megaptera novaeangliae) can shift between onshore and offshore foraging habitats depending on prey availability driven by upwelling conditions (see Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Western Gull Foraging Behavior as an Ecosystem State Indicator in Coastal California

et al. 2022

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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 occidentalis) breeding on Southeast Farallon Island as a proxy of ecosystem state in coastal California by investigating the interannual variability in gull foraging behavior from 2013 to 2019 in relation to upwelling conditions, prey abundances, and overlap with humpback whales (Megaptera novaeangliae) as gulls frequently feed in association with whales. Western gulls have a flexible diet and forage on land and at-sea. We combined gull GPS tracking data during the incubation phase, ecosystem survey data on multiple predator and prey species, and derived oceanographic upwelling products. When foraging at sea, gulls overlapped with cool upwelled waters. During 2015–2017, 25% more gull foraging trips visited land than in other years, where land trips were on average ∼8 h longer and 40% further than sea trips, which coincided with high compression of coastally upwelled waters (habitat compression) in 2015–2016. Gull foraging behavior was related to local prey abundances, where more foraging occurred near shore or on land when prey abundances were low. However, visual surveys indicated that ∼70% of humpback whale observations co-occurred with gulls, and the year with the most foraging on land (2017) corresponded to regionally low relative whale abundances, suggesting gull movement patterns could be an indicator of whale presence. Further, both whales and gulls forage near-shore under high upwelling habitat compression and low krill abundance. Hence, the deployment of year-round tags on gulls with the capability of near real-time data accessibility could provide important fine-scale metrics for conservation and management of the threatened yet recovering eastern Pacific humpback whale population between infrequent and coarse surveys. Entanglement in fishing gear and ship strikes are major inhibitors to whale recovery and have increased concomitantly with human use of ocean resources. Moreover, as climate variability and change increase, novel indicators should be explored and implemented to inform marine spatial planning and protect species across multiple scales from new risks.

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Footprints of fixed‐gear fisheries in relation to rising whale entanglements on the U.S. West Coast

Cited by 22 publications

References 49 publications

Environmental DNA provides quantitative estimates of Pacific hake abundance and distribution in the open ocean

Environmental DNA provides quantitative estimates of Pacific hake abundance and distribution in the open ocean

Marine heatwave challenges solutions to human–wildlife conflict

Western Gull Foraging Behavior as an Ecosystem State Indicator in Coastal California

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