Single and multispecies reference points for Baltic fish stocks

Gislason, Henrik

doi:10.1006/jmsc.1999.0492

Cited by 98 publications

(60 citation statements)

References 11 publications

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“…The consequences for biological reference points when M changes are not as clear, as evidenced by the difficulties in estimating biological reference points in integrated ecosystem models (Möllmann et al 2014). While multispecies modeling approaches have been used to estimate biological reference points that change with estimated changes in natural mortality (e.g., Gislason 1999;Collie and Gislason 2001;Overholtz et al 2008), these models have not so far been widely used for management purposes.…”

Section: Introductionmentioning

confidence: 99%

In what direction should the fishing mortality target change when natural mortality increases within an assessment?

Legault

Palmer

2016

Can. J. Fish. Aquat. Sci.

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Traditionally, the natural mortality rate (M) in a stock assessment is assumed to be constant. When M increases within an assessment, the question arises how to change the fishing mortality rate target (F Target ). Per recruit considerations lead to an increase in F Target , while limiting total mortality leads to a decrease in F Target . Application of either approach can result in nonsensical results. Short-term gains in yield associated with high F Target values should be considered in light of potential losses in future yield if the high total mortality rate leads to a decrease in recruitment. Examples using yellowtail flounder (Limanda ferruginea) and Atlantic cod (Gadus morhua) are used to demonstrate that F Target can change when M increases within an assessment and to illustrate the consequences of different F Target values. When a change in M within an assessment is contemplated, first consider the amount and strength of empirical evidence to support the change. When the empirical evidence is not strong, we recommend using a constant M. If strong empirical evidence exists, we recommend estimating F Target for a range of stock-recruitment relationships and evaluating the trade-offs between risk of overfishing and forgone yield.Résumé : Traditionnellement, le taux de mortalité naturelle (M) dans une évaluation de stock est présumé être constant. Quand M augmente dans une évaluation, cela soulève la question à savoir comment changer le taux cible de mortalité par pêche (F Target ). Des considérations relatives aux recrues individuelles mènent à une augmentation de F Target , alors que le fait de limiter la mortalité totale mène à une réduction de F Target . L'application d'une ou l'autre de ces approches peut se traduire par des résultats qui n'ont aucun sens. Les augmentations à court terme du rendement associées à des valeurs de F Target élevées devraient être évaluées par rapport aux réductions potentielles du rendement futur si le taux de mortalité totale élevé se traduit par une baisse du recrutement. Des exemples basés sur la limande à queue jaune (Limanda ferruginea) et la morue franche (Gadus morhua) sont utilisés pour démontrer que F Target peut changer quand M augmente dans une évaluation et pour illustrer les conséquences de différentes valeurs de F Target . Quand la possibilité de changer M dans une évaluation est examinée, il faut d'abord prendre évaluer la quantité et la force des preuves empiriques qui appuient ce changement. Si ces preuves ne sont pas fortes, nous recommandons d'utiliser un M constant. Si les preuves empiriques sont fortes, nous recommandons d'estimer F Target pour une gamme de relations stock-recrutement et d'évaluer les compromis entre le risque de surpêche et le rendement non réalisé. [Traduit par la Rédaction]

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Section: Introductionmentioning

confidence: 99%

In what direction should the fishing mortality target change when natural mortality increases within an assessment?

Legault

Palmer

2016

Can. J. Fish. Aquat. Sci.

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“…Apart from a few exceptions (Blanchard et al 2010, Bundy et al 2010, considerable effort has been devoted to analyzing indicator performance at lower hierarchical levels, from individuals to populations and communities (Gislason 1999, Jennings & Dulvy 2005, Shin et al 2005. Nevertheless, a system-level approach can be more attractive than species-oriented approaches because both the direct and indirect effects of disturbance can be considered in a single interaction network (Raffaelli 2005).…”

Section: Introductionmentioning

confidence: 99%

Biomass accumulation across trophic levels: analysis of landings for the Mediterranean Sea

Pranovi¹,

Libralato²,

Zucchetta³

et al. 2014

Mar. Ecol. Prog. Ser.

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The need to implement Ecosystem-Based-Management (EBM) in marine ecosystems and the recent adoption of European Union directives, such as the Marine Strategy Framework Directive (MSFD), make indicators that are able to describe ecosystem state particularly relevant. The trophodynamic context is promising in that it can define integrative ecosystem indicators from modelling and field data. Here we analyze energy accumulation across trophic levels (TLs), i.e. the accumulation of energy in various biomass components of an ecosystem. The analysis of biomass accumulation across TLs, previously applied to surveys and model output data, was applied to a time series (1970 to 2010) of landings in the Mediterranean Sea and its 8 sub-areas. The standardized cumulative biomass versus TL curves for each year were fit to a logistic function, revealing that the accumulation pattern was detectable using landings data and confirming prior patterns. Parameters describing the curve shape, i.e. basal biomass, inflection point and steepness, were considered as possible indicators for assessing changes of ecosystem state through time. These parameters were able to detect systems modification in terms of both space and time and exhibited differential sensitivity to external drivers. The inflection point was mainly fishery-driven, whereas steepness seems to respond to environmental features, indicating an ability to discriminate across major ecosystem drivers. The application of Monte Carlo un certainty analysis showed that all of the parameters are sufficiently robust to possible sampling errors in the TL assignment to the different taxa. Collectively, these results confirm the robustness of patterns for cumulative biomass across TL curves seen in a growing number of marine eco systems. These emergent features suggest that this approach could produce useful ecosystem indicators for the implementation of EBM and the MSFD.

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“…The MSY, a stock related indicator, is a traditional reference point (Gislason, 1999) which is often criticized because of the estimation problems contained in it, its weakness as a management goal, and the difficulty in effectively implementing harvesting strategies based on this strategy (Mace, 2001). In this paper the MSY was estimated using a multi-species model; in this way the problem of the interaction between the species and the fisheries was partially solved.…”

Section: Discussionmentioning

confidence: 99%

Comparison between Artisanal Fishery and Manila Clam Harvesting in the Venice Lagoon by Using Ecosystem Indicators: An Ecological Economics Perspective

et al. 2004

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Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in Comparison between Artisanal Fishery and Manila Clam Harvesting in the Venice Lagoon by Using Ecosystem Indicators: An Ecological Economics Perspective SummaryArtisanal fishery in the Venice lagoon is a multi-target activity with a long tradition. It was the main fishing activity till the late '80s when, after the introduction and spread of the Manila clam (Tapes philippinarum), the mechanical clam harvesting started. A mass-balance model of the lagoon ecosystem was developed using the Ecopath with Ecosim software. 73 scenarios, obtained by changing the fishing effort of the two different types of fishery, were used to explore their impact on the ecosystem. A set of indicators was applied in order to compare the two fishing activities. The results obtained showed that the two activities are strongly interlinked, even through they don't exploit the same resources. The mechanical clam harvesting could reasonably be considered to be the driving force; it is capable of determining the state of lagoon ecosystem. The above mentioned factors create a lot of conflict between the two types of fishery.

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Single and multispecies reference points for Baltic fish stocks

Cited by 98 publications

References 11 publications

In what direction should the fishing mortality target change when natural mortality increases within an assessment?

In what direction should the fishing mortality target change when natural mortality increases within an assessment?

Biomass accumulation across trophic levels: analysis of landings for the Mediterranean Sea

Comparison between Artisanal Fishery and Manila Clam Harvesting in the Venice Lagoon by Using Ecosystem Indicators: An Ecological Economics Perspective

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