Reply to Andersen et al. (2016) “Assumptions behind size-based ecosystem models are realistic”

Abstract In a recent publication (Froese et al., ICES Journal of Marine Science; 73: 1640–1650), we presented a critique of the balanced harvesting (BH) approach to fishing. A short section dealt with the size-spectrum models used to justify BH, wherein we pointed out the lack of realism of these models, which mostly represented ecosystems as consisting of a single cannibalistic species. Andersen et al. (ICES Journal of Marine Science; 73: 1651–1655) commented on our paper and suggested that we criticized size-spectrum models in general and that we supposedly made several erroneous statements. We stress that we only referred to the size-spectrum models that we cited, and we respond to each supposedly erroneous statement. We still believe that the size-spectrum models used to justify BH were highly unrealistic and not suitable for evaluating real-world fishing strategies. We agree with Andersen et al. that BH is unlikely to be a useful guiding principle for ecosystem-based fisheries management, for many reasons. The use of unrealistic models is one of them.

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Assumptions behind size-based ecosystem models are realistic

ICES Journal of Marine Science ◽

10.1093/icesjms/fsv211 ◽

2016 ◽

Vol 73 (6) ◽

pp. 1651-1655 ◽

Cited By ~ 22

Author(s):

Ken H. Andersen ◽

Julia L. Blanchard ◽

Elizabeth A. Fulton ◽

Henrik Gislason ◽

Nis Sand Jacobsen ◽

...

Keyword(s):

Density Dependence ◽

Size Spectrum ◽

Marine Science ◽

Ecosystem Models ◽

Fishing Strategies ◽

Stock Recruitment

AbstractA recent publication about balanced harvesting (Froese et al., ICES Journal of Marine Science; 73: 1640–1650) contains several erroneous statements about size-spectrum models. We refute the statements by showing that the assumptions pertaining to size-spectrum models discussed by Froese et al. are realistic and consistent. We further show that the assumption about density-dependence being described by a stock recruitment relationship is responsible for determining whether a peak in the cohort biomass of a population occurs late or early in life. Finally, we argue that there is indeed a constructive role for a wide suite of ecosystem models to evaluate fishing strategies in an ecosystem context.

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Progress on Implementing Ecosystem-Based Fisheries Management in the United States Through the Use of Ecosystem Models and Analysis

Frontiers in Marine Science ◽

10.3389/fmars.2019.00641 ◽

2019 ◽

Vol 6 ◽

Cited By ~ 6

Author(s):

Howard Townsend ◽

Chris J. Harvey ◽

Yvonne deReynier ◽

Dawn Davis ◽

Stephani G. Zador ◽

...

Keyword(s):

United States ◽

Fisheries Management ◽

The United States ◽

Ecosystem Models ◽

Ecosystem Based Fisheries Management

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Ecological data from observer programmes underpin ecosystem-based fisheries management

ICES Journal of Marine Science ◽

10.1093/icesjms/fsx032 ◽

2017 ◽

Vol 74 (6) ◽

pp. 1481-1495 ◽

Cited By ~ 12

Author(s):

Eric Gilman ◽

Mariska Weijerman ◽

Petri Suuronen

Keyword(s):

Fisheries Management ◽

Mortality Data ◽

Ecological Communities ◽

Target Species ◽

Ecological Data ◽

Ecosystem Models ◽

Management Measures ◽

Ecological Risk Assessments ◽

Ecosystem Based Fisheries Management ◽

Data Requirements

Abstract Data required from fisheries monitoring programmes substantially expand as management authorities transition to implement elements of ecosystem-based fisheries management (EBFM). EBFM extends conventional approaches of managing single fishery effects on individual stocks of target species by taking into account the effects, within a defined ecosystem, of local to regional fisheries on biodiversity, from genotypes to ecological communities. This includes accounting for fishery effects on evolutionary processes, associated and dependent species, habitats, trophic food web processes, and functionally linked systems. Despite seemingly insurmountable constraints, through examples, we demonstrate how data routinely collected in most observer programmes and how minor and inexpensive expansions of observer data fields and collection protocols supply ecological data underpinning EBFM. Observer data enable monitoring bycatch, including catch and mortality of endangered, threatened and protected species, and assessing the performance of bycatch management measures. They provide a subset of inputs for ecological risk assessments, including productivity–susceptibility analyses and multispecies and ecosystem models. Observer data are used to monitor fishery effects on habitat and to identify and protect benthic vulnerable marine ecosystems. They enable estimating collateral sources of fishing mortality. Data from observer programmes facilitate monitoring ecosystem pressure and state indicators. The examples demonstrate how even rudimentary fisheries management systems can meet the ecological data requirements of elements of EBFM.

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Developing an operational reference framework for fisheries management on the basis of a two-dimensional index of ecosystem impact

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.01.008 ◽

2005 ◽

Vol 62 (3) ◽

pp. 585-591 ◽

Cited By ~ 34

Author(s):

Sergi Tudela ◽

Marta Coll ◽

Isabel Palomera

Keyword(s):

Fisheries Management ◽

Canonical Discriminant Analysis ◽

Factorial Correspondence Analysis ◽

Ecological Indices ◽

Two Dimensional ◽

Quantitative Index ◽

Ecosystem Models ◽

Reference Framework ◽

Ecosystem Based Fisheries Management ◽

Reference Functions

Abstract A composite quantitative index for the percentage of primary production required to sustain fisheries and the average trophic level of catch (%PPR–TLc) was employed to develop ecosystem-based reference functions suitable for fisheries management. Established ecosystem models, characterized by pairs of %PPR–TLc, were classified as either sustainably exploited or ecosystem overfished, on the basis of the results of factorial correspondence analysis applied to selected ecological indices, and on information from various sources. Canonical discriminant analysis of these pairs was applied to establish the discriminant function to separate the two exploitation classes. Next, reference functions related to different probabilities of ecosystem overfishing were developed to obtain an operational framework for ecosystem-based fisheries management. Values of ecosystem-based maximum sustainable catches associated with different probabilities of belonging to a sustainable situation were calculated. Overall, results show that most current fishing scenarios entail high risks of ecosystem overfishing.

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Applying tree analysis to assess combinations of Ecosystem-Based Fisheries Management actions in Management Strategy Evaluation

Fisheries Research ◽

10.1016/j.fishres.2019.105466 ◽

2020 ◽

Vol 225 ◽

pp. 105466

Author(s):

Amanda R. Hart ◽

Gavin Fay

Keyword(s):

Fisheries Management ◽

Management Strategy ◽

Tree Analysis ◽

Management Strategy Evaluation ◽

Management Actions ◽

Strategy Evaluation ◽

Ecosystem Based Fisheries Management

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The isotopic niche of Atlantic, biting marine mammals and its relationship to skull morphology and body size

Scientific Reports ◽

10.1038/s41598-021-94610-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Massimiliano Drago ◽

Marco Signaroli ◽

Meica Valdivia ◽

Enrique M. González ◽

Asunción Borrell ◽

...

Keyword(s):

Body Size ◽

Atlantic Ocean ◽

Fisheries Management ◽

Marine Mammals ◽

Trophic Position ◽

Sympatric Species ◽

Isotopic Niche ◽

Apex Predators ◽

Skull Morphology ◽

Ecosystem Based Fisheries Management

AbstractUnderstanding the trophic niches of marine apex predators is necessary to understand interactions between species and to achieve sustainable, ecosystem-based fisheries management. Here, we review the stable carbon and nitrogen isotope ratios for biting marine mammals inhabiting the Atlantic Ocean to test the hypothesis that the relative position of each species within the isospace is rather invariant and that common and predictable patterns of resource partitioning exists because of constrains imposed by body size and skull morphology. Furthermore, we analyze in detail two species-rich communities to test the hypotheses that marine mammals are gape limited and that trophic position increases with gape size. The isotopic niches of species were highly consistent across regions and the topology of the community within the isospace was well conserved across the Atlantic Ocean. Furthermore, pinnipeds exhibited a much lower diversity of isotopic niches than odontocetes. Results also revealed body size as a poor predictor of the isotopic niche, a modest role of skull morphology in determining it, no evidence of gape limitation and little overlap in the isotopic niche of sympatric species. The overall evidence suggests limited trophic flexibility for most species and low ecological redundancy, which should be considered for ecosystem-based fisheries management.

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