Best practices for assessing forage fish fisheries-seabird resource competition

Sydeman, William J.; Thompson, Sarah; Anker‐Nilssen, Tycho; Arimitsu, Mayumi L.; Bennison, Ashley; Bertrand, Sophie; Boersch‐Supan, Philipp H.; Boyd, Charlotte; Bransome, Nicole C.; Crawford, Robert J. M.; Daunt, Francis; Furness, Robert W.; Gianuca, Dimas; Gladics, Amanda J.; Koehn, Laura E.; Lang, Jennifer; Logerwell, Elizabeth; Morris, Taryn L.; Phillips, Elizabeth M.; Provencher, Jennifer F.; Punt, André E.; Saraux, Claire; Shannon, Lynne J.; Sherley, Richard B.; Simeone, Alejandro; Wanless, Ross M.; Wanless, Sarah; Zador, Stephani G.

doi:10.1016/j.fishres.2017.05.018

Cited by 64 publications

(74 citation statements)

References 124 publications

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“…), managing forage fish landings to ameliorate competition with seabirds (Sydeman et al. ), reducing human consumption of wild meat to promote terrestrial carnivores (Ripple et al. , Foster et al.…”

Section: Discussionmentioning

confidence: 99%

“…As complex issues in wildlife conservation become increasingly apparent, so does the importance of evaluating how wildlife and human needs can be balanced through ecosystem-based management. Some studies have evaluated or proposed decreases in harvest to enhance wildlife populations, such as decreasing salmon harvest for killer whale (Williams et al 2011, Chasco et al 2017 or brown bear conservation (Levi et al 2012), managing forage fish landings to ameliorate competition with seabirds (Sydeman et al 2017), reducing human consumption of wild meat to promote terrestrial carnivores (Ripple et al 2015, Foster et al 2016, and limiting krill harvest for ecological concerns (Nicol and Endo 1999). Direct observation of prey intake is often difficult.…”

Section: Discussionmentioning

confidence: 99%

“…, Sydeman et al. ). Consequently, a multispecies, ecosystem‐based approach is needed to fully evaluate the effects of fisheries.…”

Section: Introductionmentioning

confidence: 98%

“…Effort has been made to reduce the direct effects of harvest on nontarget species (e.g., bycatch reduction), but harvest may also indirectly affect both predators and prey of the organism being captured. This problem has been recognized in studies evaluating competition between harvest of fishes and their consumption by marine mammals (Trites et al 1997) and between krill and seabirds (Karpouzi et al 2007, Sydeman et al 2017). Consequently, a multispecies, ecosystem-based approach is needed to fully evaluate the effects of fisheries.…”

Section: Introductionmentioning

confidence: 99%

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Managing salmon for wildlife: Do fisheries limit salmon consumption by bears in small Alaskan streams?

Lincoln

Hilborn

Wirsing

et al. 2020

Ecological Applications

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Ecosystem‐based management requires consideration of overlapping resource use between humans and other consumers. Pacific salmon are an important resource for both fisheries and populations of wildlife around the Pacific rim, including coastal brown bears (Ursus arctos); salmon consumption has been positively linked to bear density, body size, and reproductive rate. As a case study within the broader context of human–wildlife competition for food, we used 16–22 yr of empirical data in four different salmon‐bearing systems in southwestern Alaska to explore the relationship between sockeye salmon (Oncorhynchus nerka) availability and consumption by bears. We found a negative relationship between the annual biomass of salmon available to bears and the fraction of biomass consumed per fish, and a saturating relationship between salmon availability and the total annual biomass of salmon consumed by bears. Under modeled scenarios, bear consumption of salmon was predicted to increase only with dramatic (on the order of 50–100%) increases in prey availability. Even such large increases in salmon abundance were estimated to produce relatively modest increases in per capita salmon consumption by bears (2.4–4.8 kg·bear−1·d−1, 15–59% of the estimated daily maximum per capita intake), in part because bears did not consume salmon entirely, especially when salmon were most available. Thus, while bears catching salmon in small streams may be limited by salmon harvest in some years, current management of the systems we studied is sufficient for bear populations to reach maximum salmon consumption every 2–4 yr. Consequently, allocating more salmon for brown bear conservation would unlikely result in an ecologically significant response for bears in these systems, though other ecosystem components might benefit. Our results highlight the need for documenting empirical relationships between prey abundance and consumption, particularly in systems with partial consumption, when evaluating the ecological response of managing prey resources for wildlife populations.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…, Sydeman et al. ). Consequently, a multispecies, ecosystem‐based approach is needed to fully evaluate the effects of fisheries.…”

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Managing salmon for wildlife: Do fisheries limit salmon consumption by bears in small Alaskan streams?

Lincoln

Hilborn

Wirsing

et al. 2020

Ecological Applications

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show abstract

“…The potential impacts of fisheries include the indirect effects of prey removal upon the predators of fished species, particularly "forage" species such as anchovies (Engraulidae), sardines (Clupeidae) and krill (Euphausiidae) (Hilborn et al, 2017;Pikitch et al, 2014;Sydeman et al, 2017). The majority of predation on forage species is due to other species of fish (Furness, 2002) but public interest tends to be more concerned with seabirds and marine mammals, which have significant value as flagship species (sensu Zacharias & Roff, 2001), as an economic and cultural resource (e.g., as the focus of ecotourism), and as indicators of the state of the wider ecosystem (Croxall et al, 2012;Schipper et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Reference points for predators will progress ecosystem‐based management of fisheries

et al. 2020

Self Cite

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Ecosystem‐based management of fisheries aims to allow sustainable use of fished stocks while keeping impacts upon ecosystems within safe ecological limits. Both the FAO Code of Conduct for Responsible Fisheries and the Aichi Biodiversity Targets promote these aims. We evaluate implementation of ecosystem‐based management in six case‐study fisheries in which potential indirect impacts upon bird or mammal predators of fished stocks are well publicized and well studied. In particular, we consider the components needed to enable management strategies to respond to information from predator monitoring. Although such information is available in all case‐studies, only one has a reference point defining safe ecological limits for predators and none has a method to adjust fishing activities in response to estimates of the state of the predator population. Reference points for predators have been developed outside the fisheries management context, but adoption by fisheries managers is hindered a lack of clarity about management objectives and uncertainty about how fishing affects predator dynamics. This also hinders the development of adjustment methods because these generally require information on the state of ecosystem variables relative to reference points. Nonetheless, most of the case‐studies include precautionary measures to limit impacts on predators. These measures are not used tactically and therefore risk excessive restrictions on sustainable use. Adoption of predator reference points to inform tactical adjustment of precautionary measures would be an appropriate next step towards ecosystem‐based management.

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Predicting the distribution of foraging seabirds during a period of heightened environmental variability

Evans

Lea

Hindell

2021

Ecological Applications

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Quantifying the links between the marine environment, prey occurrence, and predator distribution is the first step towards identifying areas of biological importance for marine spatial planning. Events such as marine heatwaves result in an anomalous change in the physical environment, which can lead to shifts in the structure, biomass, and distribution of lower trophic levels. As central‐place foragers, seabirds are vulnerable to changes in their foraging grounds during the breeding season. We first quantified spatiotemporal variability in the occurrence and biomass of prey in response to an abrupt change in oceanography as a result of a marine heatwave event. Secondly, using multivariate techniques and machine learning, we investigated if differences in the foraging technique and prey of seabirds resulted in varying responses to changes in prey occurrence and the environment over a 2.5‐yr period. We found that the main variables correlated with seabird distribution were also important in structuring the occurrence and biomass of prey; sea‐surface temperature (SST), current speed, mixed‐layer depth, and bathymetry. Both zooplankton biomass and the occurrence of fish schools exhibited negative relationships with temperature, and temperature was subsequently an important variable in determining seabird distribution. We were able to establish correlations between the distribution of prey and the spatiotemporal distribution of albatross, little penguins and common‐diving petrels. We were unable to find a correlation between the distribution of prey and that of short‐tailed shearwaters and fairy prions. For high‐use coastal areas, the delineation of important foraging regions is essential to balance human use of an area with the needs of marine predators, particularly seabirds.

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Best practices for assessing forage fish fisheries-seabird resource competition

Cited by 64 publications

References 124 publications

Managing salmon for wildlife: Do fisheries limit salmon consumption by bears in small Alaskan streams?

Managing salmon for wildlife: Do fisheries limit salmon consumption by bears in small Alaskan streams?

Reference points for predators will progress ecosystem‐based management of fisheries

Predicting the distribution of foraging seabirds during a period of heightened environmental variability

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