Improving management decisions by predicting fish bycatch in the Barents Sea shrimp fishery
Aldrin, Magne; Mortensen, Bjørnar; Storvik, Geir; Nedreaas, Kjell Harald; Aglen, Asgeir; Aanes, Sondre
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/108394Utgivelsesdato
2011-11-20Metadata
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Originalversjon
http://dx.doi.org/10.1093/icesjms/fsr172Sammendrag
When the bycatch of juvenile fish within the Barents Sea shrimp fishery is too large, the area is closed to fishing for a certain period. Bycatch is estimated from sampled trawl hauls, for which the shrimp yield is recorded, along with the total number of various
bycatch fish species. At present, bycatch estimation is based on a simple estimator, the sum of the number of fish caught within the area of interest within a small time window, divided by the corresponding shrimp yield (in weight). No historical data are used. A model-based estimation is proposed in which spatio-temporal models are constructed for the variation in both the yield
of shrimp and the amount of bycatch in space and time. The main effects are described through generalized additive models, and local dependence structures are specified through correlated random effects. Model estimation includes historical and recent data. Experiments with both simulated and real data show that the model-based estimator outperforms the present simple estimator when a low or moderate number of samples (e.g. <20) is available, whereas the two estimators are equally good when the number of samples is high.