Collapse and recovery of forage fish populations prior to commercial exploitation

McClatchie, Sam; Hendy, I. L.; Thompson, Andrew R.; Watson, William

doi:10.1002/2016gl071751

Cited by 57 publications

(38 citation statements)

References 33 publications

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“…These time scales are similar to those discussed in other studies on the recovery of fished populations after collapse (Neubauer et al, 2013; Petitgas, Secor, McQuinn, Huse, & Lo, 2010). Paleo records of anchovy and sardine abundance of the California coast indicate an average time of 1–2 decades to return to “fishable biomass” (33% of mean peak biomass) (McClatchie et al (2017). Recovery is not inevitable: only 4 of 12 stocks that had remained collapsed for 11 or more years had recovered above the 30% threshold by the end of the time series.…”

Section: Discussionmentioning

confidence: 99%

“…Other fisheries meta‐analyses have taken a similar approach of defining collapse with a reference point determined from the time series themselves to standardize comparisons (e.g. Essington et al, 2015; McClatchie et al, 2017; Mullon, Fréon, & Cury, 2005; Pinsky et al, 2011; Worm et al, 2009). Applying alternative thresholds did not substantially change our conclusions except for the Random Survival Forest model of low biomass durations.…”

Section: Discussionmentioning

confidence: 99%

“…Fish population collapses are often defined in reference to the biomass at maximum sustainable yield ( B MSY ), which provides a defensible theoretical basis and management relevance (Neubauer et al, 2013; Pinsky et al, 2011). However, estimates of absolute abundance are unreliable (Hilborn, 2002), and when combined with the frequency of large‐scale fluctuations and regime shifts in forage fish, make MSY and B MSY difficult to estimate (McClatchie, Hendy, Thompson, & Watson, 2017). Instead, we focus on relative trends from surveys and stock assessments since these can be more accurately estimated and still provide information on the potential extent and duration of low abundance, assuming consistency in survey and assessment methodology within a time series.…”

Section: Methodsmentioning

confidence: 99%

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The highs and lows of herring: A meta‐analysis of patterns and factors in herring collapse and recovery

et al. 2020

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Pacific and Atlantic herring populations (genus Clupea) commonly experience episodic collapse and recovery. Recovery time durations are of great importance for the sustainability of fisheries and ecosystems. We collated information from 64 herring populations to characterize herring fluctuations and determine the time scales at low biomass and at high and low recruitment, and use generalized linear models and Random Survival Forests to identify the most important bottom‐up, top‐down and intrinsic factors influencing recovery times. Compared to non‐forage fish taxa, herring decline to lower minima, recover to higher maxima and show larger changes in biomass, implying herring are more prone to booms and busts than non‐forage fish species. Large year classes are more common in herring, but occur infrequently and are uncorrelated among regionally grouped stocks, implying local drivers of high recruitment. Management differs between Pacific and Atlantic herring fisheries, where at similarly low biomass, Pacific fisheries tend to be closed while Atlantic fisheries remain open. This difference had no apparent effect on herring recovery times, which averaged 11 years, although most stocks with longer recovery periods had not yet recovered at the end of the observation period. Biomass recovery is best explained by median recruitment and variability in sea surface height anomalies and sea surface temperatures—higher variability leads to shorter recovery times. In addition, the duration of recruitment failure is closely linked with low biomass. While recovery times rely on the nature of the relationship between spawning biomass and recruitment, they are still largely governed by complex and uncertain processes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The highs and lows of herring: A meta‐analysis of patterns and factors in herring collapse and recovery

et al. 2020

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“…and albacore tuna Thunnus alalunga, protected species such as humpback whale Megaptera novaeangliae, and numerous species of protected seabirds (Szoboszlai et al 2015, Koehn et al 2016. Sardine and anchovy have fluctuated strongly in abundance over the past 500− 1700 yr (Baumgartner et al 1992, McClatchie et al 2017, and recently both species have declined to less than 10% of contemporary peak abundances (Hill et al 2015, Thayer et al 2017. This has led to the closure of a sardine fishery valued at US$21 million in 2012, and has raised concerns regarding effects on predators and the broader ecosystem (though Zwolinski et al 2017 suggest early signs of an increase in anchovy stock biomass in 2016).…”

Section: Introductionmentioning

confidence: 99%

A multi-model approach to understanding the role of Pacific sardine in the California Current food web

Kaplan¹,

Francis²,

Punt³

et al. 2019

Mar. Ecol. Prog. Ser.

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We develop a multi-model approach to explore how abundance of a forage fish (Pacific sardine Sardinops sagax) impacts the ecosystem and predators in the California Current, a region where sardine and anchovy Engraulis mordax have recently declined to less than 10% of contemporary peak abundances. We developed or improved applications of 3 ecosystem modeling approaches: Ecopath, Model of Intermediate Complexity for Ecosystem assessment (MICE), and Atlantis. We also used Ecopath diets to predict impacts to predators using a statistical generalization of the dynamic Ecosim model (Predator Response to the Exploitation of Prey [PREP]). Models that included brown pelican Pelecanus occidentalis at the species level (MICE and Ecopath/PREP) both predict moderate to high vulnerability of brown pelicans to low sardine abundance. This vulnerability arises because sardine comprises a large fraction of their diet, and because other important prey (anchovy) also exhibit large population fluctuations. Two of the ecosystem models (MICE and Atlantis) suggest that California sea lions Zalophus californianus exhibit relatively minor responses to sardine depletion, due to having broader diets and lower reliance on another fluctuating species, anchovy. On the other hand, Ecopath/PREP suggests that sardine declines will have a stronger impact on California sea lions. This discrepancy may in part reflect structural differences in the models: Atlantis and MICE explicitly represent density dependence and age-structure, which can mitigate effects of prey depletion in these models. Future work should identify fisheries management strategies that are robust to uncertainties within and among models, rather than relying on single models to assess ecosystem impacts of management and forage fish abundance. KEY WORDS: Forage fish • Pacific sardine • California Current • Ecosystem model • California sea lion • Brown pelican • Multi-model approach Contribution to the Theme Section 'Drivers of dynamics of small pelagic fish resources: biology, management and human factors'

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“…Quantifying trade‐offs between different human priorities for forage fish is complicated by the fact that forage fish dynamics are highly variable and hard to predict. Forage fish characteristically undergo high‐amplitude fluctuations in productivity, which occur in the absence of fishing (Chavez, Ryan, Lluch‐Cota, & Niquen, ; McClatchie, Hendy, Thompson, & Watson, ) but can be amplified by fishing when productivity drops rapidly and management fails to respond (Dickey‐Collas et al., ; Essington et al., ). Regardless of their cause, collapses in forage fish abundance affect the livelihoods of those involved in fishing and processing and can cause shifts in predator diet, abundance and reproductive success (e.g., Francis, Hare, Hollowed, & Wooster, ; Kaplan et al., ; Kitaysky, Wingfield, & Piatt, ; Punt, MacCall, et al., ).…”

Section: Introductionmentioning

confidence: 99%

Forage fish fisheries management requires a tailored approach to balance trade‐offs

2018

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Ecosystem‐based fishery management requires considering the effects of actions on social, natural and economic systems. These considerations are important for forage fish fisheries, because these species provide ecosystem services as a key prey in food webs and support valuable commercial fisheries. Forage fish stocks fluctuate naturally, and fishing may make these fluctuations more pronounced, yet harvest strategies intended to ameliorate these effects might adversely affect fisheries and communities. Here, we evaluate trade‐offs among a diverse suite of management objectives by simulating outcomes from several harvest strategies on forage fish species. We demonstrate that some trade‐offs (like those between catches and minimizing collapse length) were universal among forage species and could not be eliminated by the use of different control rules. We also demonstrate that trade‐offs vary among forage fish species, with strong trade‐offs between stable, high catches and high‐biomass periods (“bonanzas”) for menhaden‐ and anchovy‐like fish, and counterintuitive trade‐offs for sardine‐like fish between shorter collapses and longer bonanzas. We find that harvest strategies designed to maintain stability in catches will result in more severe collapses. Finally, we show that the ability of assessments to detect rapid changes in population status greatly affects control rule performance and the degree and type of trade‐offs, increasing the risk and severity of collapses and reducing catches. Together, these results demonstrate that while default harvest strategies are useful in data‐poor situations, management strategy evaluations that are tailored to specific forage fish may better balance trade‐offs.

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Collapse and recovery of forage fish populations prior to commercial exploitation

Cited by 57 publications

References 33 publications

The highs and lows of herring: A meta‐analysis of patterns and factors in herring collapse and recovery

The highs and lows of herring: A meta‐analysis of patterns and factors in herring collapse and recovery

A multi-model approach to understanding the role of Pacific sardine in the California Current food web

Forage fish fisheries management requires a tailored approach to balance trade‐offs

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