Towards an ecosystem approach to fisheries management (EAFM) when trawl surveys provide the main source of information

Cotter, John; Petitgas, Pierre; Abella, Álvaro; Apostolaki, Panayiota; Mesnil, Benoît; Politou, Chrissi‐Yianna; Rivoirard, Jacques; Rochet, Marie Joelle; Spedicato, María Teresa; Trenkel, Verena M.; Woillez, Mathieu

doi:10.1051/alr/2009025

Cited by 35 publications

(32 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conventional survey data provide information about trends in population abundance and the size structure of catchable fish species (Cotter et al, 2009), from which both the LFI and the LSI can be estimated, although both indices may require interpretation before being applied to new systems. The definition of the LSI involves the concept of the size of a species, specified by its maximum length L max .…”

Section: The Lfi and Lsi: Complementary Indicatorsmentioning

confidence: 99%

Size-selective fishing drives species composition in the Celtic Sea

Shephard

Fung

Houle

et al. 2012

ICES Journal of Marine Science

View full text Add to dashboard Cite

Fishing alters community size structure by selectively removing larger individual fish and by changing the relative abundance of different-sized species. To assess the relative importance of individual-and species-level effects, two indices of fish community structure were compared, the relative abundance of large fish individuals (large fish indicator, LFI) and the relative abundance of large fish species (large species indicator, LSI). The two indices were strongly correlated for empirical data from the Celtic Sea and for data from simulated model communities, suggesting that much of the variability in the LFI is caused by shifts in the relative abundance of species (LSI). This correlation is explained by the observation that most of the biomass of a given species is spread over few length classes, a range spanning the factor 2 of individual length, such that most species contributed predominantly to either the small or the large component of the LFI. The results suggest that the effects of size-selective fishing in the Celtic Sea are mediated mainly through changes in community composition.

show abstract

Section: The Lfi and Lsi: Complementary Indicatorsmentioning

confidence: 99%

Size-selective fishing drives species composition in the Celtic Sea

Shephard

Fung

Houle

et al. 2012

ICES Journal of Marine Science

View full text Add to dashboard Cite

show abstract

“…In our Bayesian approach, the way catches are used only serves setting minimum biomass levels that explain the level of catches, thus avoiding unrealistic low biomass level estimates. Cotter et al (2009) and Mesnil et al (2009) have recently presented some ideas and considerations on the advantages and drawbacks of using fishery-independent stock assessment methods. Survey-based methods avoid the introduction of catch data uncertainty and the temporal delay of the assessment as they provide direct information on the status of the stock while they do not require an estimation of questionable assessment parameters such as natural mortality values.…”

Section: Discussionmentioning

confidence: 99%

Applying a two-stage Bayesian dynamic model to a short lived species, the anchovy in the Aegean Sea (Eastern Mediterranean). Comparison with an Integrated Catch at Age stock assessment model.

et al. 2014

View full text Add to dashboard Cite

Two different stock assessment models were applied to the North Aegean Sea anchovy stock (Eastern Mediterranean Sea): an Integrated Catch at age Analysis and a Bayesian two-stage biomass based model. Commercial catch data over the period 2000-2008 as well as acoustics and Daily Egg Production Method estimates over the period 2003-2008 were used. Both models results were consistent, indicating that anchovy stock is exploited sustainably in relation to an exploitation rate reference point. Further, the stock biomass appears stable or increasing. However, the limitations in age-composition data, potential problems related to misinterpretation of age readings along with the existence of missing values in the survey data seem to favour the two-stage biomass method, which is based on a simplified age structure.

show abstract

“…In this study, simulation results are also considered as knowledge that relies principally upon fishery-independent information (Cotter et al 2009a).…”

Section: Discussionmentioning

confidence: 99%

“…It is also potentially useful for several other objectives, such as to check the validity of assessment and management methods and to see whether unrealistic values are being considered in designing stock dynamics (e.g. Cotter et al 2009a). Furthermore, simulations are used to describe the dynamics of populations, to verify their current status and to make projections about stocks in the future, under defined conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics

Spedicato

Poulard

Politou

et al. 2010

Aquat. Living Resour.

Self Cite

View full text Add to dashboard Cite

-Simulation of fisheries systems is a widely used approach that integrates monitoring and assessment tools. We applied the ALADYM (age-length based dynamic model) simulation model to three different studies aimed at investigating correlations between pressure and population metrics, exploring the viability of different mortality levels in long-term scenarios and predicting the effects of combined management measures. Uncertainty was incorporated into the simulations following the Monte Carlo paradigm. Three stocks were used for these exercises: red mullet in the central-southern Tyrrhenian Sea and European hake in both the Bay of Biscay and the Aegean Sea. The analysis of the relationships between total mortality and indicators highlighted significant pairwise negative correlations for red mullet. These signals of decline were supported by the spawning potential ratio indicator (mean exploited to mean unexploited spawning-stock biomass ESSB/USSB), which was low compared to target levels. It only remained within safe bounds (> 0.2; probability: 0.90-0.95) at total mortality levels lower than 1.6. The simulation results for European hake in the Bay of Biscay showed that a sustainable exploitation rate might range from 0.87 to 1.04. The benefits of combined management measures were demonstrated for European hake in the Aegean Sea, and with a further dataset on the Eastern cod stock in the Baltic Sea.

show abstract

Towards an ecosystem approach to fisheries management (EAFM) when trawl surveys provide the main source of information

Cited by 35 publications

References 93 publications

Size-selective fishing drives species composition in the Celtic Sea

Size-selective fishing drives species composition in the Celtic Sea

Applying a two-stage Bayesian dynamic model to a short lived species, the anchovy in the Aegean Sea (Eastern Mediterranean). Comparison with an Integrated Catch at Age stock assessment model.

Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics

Contact Info

Product

Resources

About