Forage species in predator diets: Synthesis of data from the California Current

Szoboszlai, Amber I.; Thayer, Julie A.; Wood, Spencer A.; Sydeman, William J.; Koehn, Laura E.

doi:10.1016/j.ecoinf.2015.07.003

Cited by 69 publications

(59 citation statements)

References 29 publications

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“…northern anchovy, Pacific sardine and market squid), krill and juvenile groundfish (particularly rockfish) and other epipelagic micronekton (e.g. pelagic squid and mesopelagic fishes) as forage (Sydeman et al 2001, Weise & Harvey 2008, Thayer et al 2014, Glaser et al 2015, Fleming et al 2016, as illustrated by the high rankings of these groups in a meta-analysis of forage needs throughout the California Current ecosystem (CCE) (Ainley et al 2015, Szoboszlai et al 2015. In addition, there are 3 na tio nal marine sanctuaries located in the GoF/MB: Cor dell Bank, Gulf of the Farallones and Monterey Bay (Fig.…”

Section: Study Areamentioning

confidence: 99%

“…Although no sampling gear is effective at sampling the entire suite of organisms in any given habitat, this trawl gear is effective at catching a representative sample of the epipelagic micronekton. For example, species representing 12 of the 20 most frequently occurring taxa in higher trophic level predator studies are well sampled (occur in 10% or more of trawls) in this survey, including 8 of the top 10 (Ainley et al 2015, Szoboszlai et al 2015.…”

Section: Species Selectionmentioning

confidence: 99%

“…Moreover, during El Niño and anomalous warm ocean events (such as the unusually low productivity conditions of Peterson et al 2006), the cool water community of groundfish, squid and krill is typically found at considerably lower abundance levels, and oceanic species such as the ribbonfish king-of-the-salmon Trachipterus altivelis and subtropical species, such as pelagic red crabs Pleuroncodes planipes and California lizardfish Syn-odus lucioceps, are more likely to be transported into the region (Leising et al 2015, Sakuma et al 2016. Although these species collectively represent some of the most important forage taxa available to higher trophic level predators (piscivorous fishes, marine mammals and seabirds; Ainley & Hyrenbach 2010, Kaplan et al 2013, Brodeur et al 2014, Szoboszlai et al 2015, it is unknown how variability in the diversity of this assemblage might be used to index variability in ecosystem processes and productivity resulting from anomalous ocean climate events or other impacts.…”

Section: Introductionmentioning

confidence: 99%

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Impacts of ocean climate variability on biodiversity of pelagic forage species in an upwelling ecosystem

Santora¹,

Hazen²,

Schroeder³

et al. 2017

Mar. Ecol. Prog. Ser.

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Monitoring essential marine biodiversity variables is an effective means for assessing impacts of climate change and human-related stressors such as pollution, overfishing and habitat destruction. Yet little is known about the natural variability of biodiversity in pelagic upwelling marine ecosystems, which are often subject to substantial interannual and decadal variability of ocean climate conditions. Using data from a pelagic midwater trawl survey, we quantified diversity indices of epipelagic forage species collected over 26 yr (1990 to 2015) to determine the natural variability and environmental determinants of biodiversity within the California Current upwelling ecosystem. Biodiversity time series indicate there are 2 alternate forage species assemblages that relate to differences in cool/strong and warm/weak upwelling years that vary in 3 to 5 yr cycles. Cooler years are associated with increased biodiversity of juvenile groundfish, whereas warm years coincide with increased biodiversity of coastal and mesopelagic fishes and species originating from southern and subtropical waters. During 2015, a year of anomalous warm surface ocean conditions, we observed unprecedented high levels of biodiversity and attribute it to high abundance of juvenile groundfish combined with an unusually high transport of subtropical and offshore species into neritic waters. Using a combination of remote sensing and in situ hydrographic data, we compare 2015 to previous anomalous ocean climate conditions and discuss how biodiversity of forage species may impact trophodynamics of upwelling ecosystems and predator−prey interactions. Attributing changes in marine biodiversity to productivity cycles and anomalous climate events, and detecting long-term biodiversity trends, provides a critical index toward understanding climate forcing on upwelling ecosystems.

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Section: Study Areamentioning

confidence: 99%

Section: Species Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impacts of ocean climate variability on biodiversity of pelagic forage species in an upwelling ecosystem

Santora¹,

Hazen²,

Schroeder³

et al. 2017

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Diet patterns generally shift through space and time as abundances of different prey species ebb and flow (Link and Garrison, 2002). Therefore, longer time series of diets over larger spatial scales than are currently available that include sizes of both predators and prey would help elucidate trophic relationships (Szoboszlai et al, 2015). Although improving precision substantially may involve collecting prohibitively large numbers of lingcod stomachs, collecting lingcod stomachs directly from a potential fishery could in fact provide an opportunity for adaptive management.…”

mentioning

confidence: 99%

Evaluating the effect of a selective piscivore fishery on rockfish recovery within marine protected areas

Oken

Essington

2016

ICES Journal of Marine Science

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Oken, K. L., and Essington, T. E. Evaluating the effect of a selective piscivore fishery on rockfish recovery within marine protected areas. -ICES Journal of Marine Science, 73: 2267-2277. Received 14 January 2016; revised 28 March 2016; accepted 8 April 2016Although ecosystem-based fisheries management is often associated with trade-offs between conflicting demands for ecosystem services, the holistic ecological considerations the approach promotes may sometimes lead to novel solutions that benefit both conservation and fisheries. Directed fishing on large piscivorous fish can reduce predation on prey and thereby benefit those populations, but incidental take of prey species in these fisheries may negate or even reverse the benefit. Whether benefits from reduced predation outweigh the costs of increased fishing will depend on the relative strength of each mortality source and the sensitivity of the population to mortality at different life stages. In the California Current, predatory lingcod (Ophiodon elongatus) populations recovered rapidly from fishing exploitation over the past two decades, while recovery of some rockfish species (Sebastes spp.) has been slow, mainly because of low natural productivities. One management tool has been the adoption of rockfish conservation areas (RCAs) that prohibit bottom contact fishing gear. Because lingcod also inhabit RCAs, fishers have been unable to catch their sustainable lingcod quotas. Therefore, we explored the conditions under which opening RCAs to a selective lingcod fishery might permit rockfish recovery despite the potential bycatch. We developed a joint equilibrium model of the two populations and analysed scenarios to assess the sensitivity of the model's predictions to key uncertainties. The model suggests a wide range of fishery and ecological conditions under which a lingcod fishery may not harm rockfish populations. However, a sensitivity analysis indicated that the range of fishing scenarios where rockfish are not harmed is highly sensitive to assumptions regarding the nature of the trophic linkage between lingcod and rockfish. We conclude that consideration of trophic interactions may reveal new fishing opportunities that meet both ecological and human goals, but precise predictions of the outcomes will require more detailed models and adaptive management.

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“…However, no definition of what constitutes a Bmajor^prey species is provided in the EFH regulations, and syntheses of groundfish food habits literature are limited and highly generalized (e.g., DuFault et al 2009;Szoboszlai et al 2015).…”

mentioning

confidence: 99%

Diet composition and foraging ecology of U.S. Pacific Coast groundfishes with applications for fisheries management

2016

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Determining the prey composition and foraging habitats of U.S. Pacific Coast groundfishes are specified management directives that have not received much scientific attention. To address this knowledge gap, we conducted a meta-analysis of the feeding ecology of 18 commercially important species and their life stages during a recent review of Pacific Coast groundfish essential fish habitat. A Major Prey Index was developed to evaluate relative importance among 47 prey taxa. Based on this metric, unidentified teleosts, euphausiids, and brachyuran crabs were the most important prey groups. When 14 generalized prey categories were used, fishes represented the dominant taxon (mean % weight or volume = 32.3) followed by shrimps (11.5), crabs (10.0), and euphausiids (9.5). PERMANOVA results indicated that species-specific differences were the primary source of dietary variability among tested variables (life stage, functional group, taxonomic group). Pacific Coast groundfishes mainly were characterized as mesopredators with estimated trophic levels ranging from 3.4 to 4.2. Foraging habitats differed significantly among functional (benthic, demersal, pelagic) and taxonomic (elasmobranch, roundfish, rockfish, flatfish) groups. Using hierarchical agglomerative cluster analysis, we identified a significantly distinct trophic guild that consumes mainly polychaetes and hard-shelled molluscs (juvenile, juvenile-adult Dover Sole; juvenile-adult English Sole) and another that specializes on euphausiids (juvenile Pacific Hake; juvenile-adult Darkblotched Rockfish). Our findings filled substantial data gaps in the trophic ecology and habitatbased management of commercially important species and can be used to inform future reviews of Pacific Coast groundfish essential fish habitat.

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Forage species in predator diets: Synthesis of data from the California Current

Cited by 69 publications

References 29 publications

Impacts of ocean climate variability on biodiversity of pelagic forage species in an upwelling ecosystem

Impacts of ocean climate variability on biodiversity of pelagic forage species in an upwelling ecosystem

Evaluating the effect of a selective piscivore fishery on rockfish recovery within marine protected areas

Diet composition and foraging ecology of U.S. Pacific Coast groundfishes with applications for fisheries management

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