The overfishing debate: an eco-evolutionary perspective

Palkovacs, Eric P.

doi:10.1016/j.tree.2011.08.004

Cited by 37 publications

(31 citation statements)

References 10 publications

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“…In parallel, the bottom-up effects of wind stress on the primary production will also affect predation up the food web, and hence the growth rate and size of fish. Because pelagic ecosystems are highly size-structured, fishing-and climate-induced changes in body size impact trophic interactions and thus food web dynamics [49]. Whereas those are explicitly accounted for in OSMOSE, other additional effects on life-history traits and their propagation through the food web could be considered.…”

Section: Discussionmentioning

confidence: 99%

Combined Fishing and Climate Forcing in the Southern Benguela Upwelling Ecosystem: An End-to-End Modelling Approach Reveals Dampened Effects

et al. 2014

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The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N2P2Z2D2-OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability.

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Section: Discussionmentioning

confidence: 99%

Combined Fishing and Climate Forcing in the Southern Benguela Upwelling Ecosystem: An End-to-End Modelling Approach Reveals Dampened Effects

et al. 2014

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“…Such size-dependent shifts in seed predation could be difficult to reverse if commercial fisheries induce evolutionary changes in frugivorous fish populations to smaller individuals that mature early (Palkovacs, 2011). Overfishing could change the nature of fruit-fish relationships from primarily mutualistic to increasingly antagonistic with negative consequences for plant community structure and diversity.…”

Section: Consequences Of Overharvesting Frugivorous Fishesmentioning

confidence: 99%

“…Globally, selective harvesting of fish concentrates on large individuals, inducing changes in population structure by favoring the survival of smaller fishes that reproduce earlier (Allan et al, 2005;Palkovacs, 2011). A fishery-induced reduction in body size of frugivorous species would have profound effects on plant regeneration if larger fishes are better seed dispersers than smaller fishes Correa et al, 2015;Galetti et al, 2008;Kubitzki and Ziburski, 1994).…”

Section: Introductionmentioning

confidence: 99%

“…By the early 1990s, stocks of Colossoma macropomum in the Central Amazon were already overexploited (Isaac and Ruffino, 1996) and commercial and recreational fishing activities have reduced population sizes of Piaractus mesopotamicus in the Pantanal by 90% (Albuquerque et al, 2012;Peixer et al, 2007). In addition to population declines, overfishing likely has shifted body size of these species to smaller individuals that reproduce earlier (Palkovacs, 2011), however the lack of basin-wide continuous historic fishery statistics (Mateus et al, 2004;Ruffino, 2008) hinders our ability to assess changes in population structure of overexploited populations. Striking population declines in other large species such as catfishes have shifted fishing pressure to under-exploited stocks of large frugivorous fishes in remote locations (Agudelo et al, 2012;Albuquerque et al, 2012;Mateus et al, 2004;Reinert and Winter, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Overfishing disrupts an ancient mutualism between frugivorous fishes and plants in Neotropical wetlands

Correa

Araujo

Penha

et al. 2015

Biological Conservation

122

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“…There is increasing concern over the potential genetic effects of the harvesting of marine fish (Laikre & Ryman ; Law ; Allendorf et al . ; Palkovacs ). Such genetic changes can either result from genetic drift caused by a reduction in population size or from natural selection.…”

mentioning

confidence: 99%

So long to genetic diversity, and thanks for all the fish

2013

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The world faces a global fishing crisis. Wild marine fisheries comprise nearly 15% of all animal protein in the human diet, but, according to the U.N. Food and Agriculture Organization, nearly 60% of all commercially important marine fish stocks are overexploited, recovering, or depleted (FAO ; Fig. ). Some authors have suggested that the large population sizes of harvested marine fish make even collapsed populations resistant to the loss of genetic variation by genetic drift (e.g. Beverton ). In contrast, others have argued that the loss of alleles because of overfishing may actually be more dramatic in large populations than in small ones (Ryman et al. 1995). In this issue, Pinsky & Palumbi (2014) report that overfished populations have approximately 2% lower heterozygosity and 12% lower allelic richness than populations that are not overfished. They also performed simulations which suggest that their estimates likely underestimate the actual loss of rare alleles by a factor of three or four. This important paper shows that the harvesting of marine fish can have genetic effects that threaten the long‐term sustainability of this valuable resource.

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The overfishing debate: an eco-evolutionary perspective

Cited by 37 publications

References 10 publications

Combined Fishing and Climate Forcing in the Southern Benguela Upwelling Ecosystem: An End-to-End Modelling Approach Reveals Dampened Effects

Combined Fishing and Climate Forcing in the Southern Benguela Upwelling Ecosystem: An End-to-End Modelling Approach Reveals Dampened Effects

Overfishing disrupts an ancient mutualism between frugivorous fishes and plants in Neotropical wetlands

So long to genetic diversity, and thanks for all the fish

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