Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic
Abstract MacNeil, M. A., Carlson, J. K., and Beerkircher, L. R. 2009. Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic. – ICES Journal of Marine Science, 66: 708–719. A suite of modelling approaches was employed to analyse shark depredation rates from t...
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsp022 http://academic.oup.com/icesjms/article-pdf/66/4/708/29132122/fsp022.pdf |
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croxfordunivpr:10.1093/icesjms/fsp022 2024-06-09T07:48:38+00:00 Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic MacNeil, M. Aaron Carlson, John K. Beerkircher, Lawrence R. 2009 http://dx.doi.org/10.1093/icesjms/fsp022 http://academic.oup.com/icesjms/article-pdf/66/4/708/29132122/fsp022.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 66, issue 4, page 708-719 ISSN 1095-9289 1054-3139 journal-article 2009 croxfordunivpr https://doi.org/10.1093/icesjms/fsp022 2024-05-10T13:16:27Z Abstract MacNeil, M. A., Carlson, J. K., and Beerkircher, L. R. 2009. Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic. – ICES Journal of Marine Science, 66: 708–719. A suite of modelling approaches was employed to analyse shark depredation rates from the US Atlantic pelagic longline fishery. As depredation events are relatively rare, there are a large number of zeroes in pelagic longline data and conventional generalized linear models (GLMs) may be ineffective as tools for statistical inference. GLMs (Poisson and negative binomial), two-part (delta-lognormal and truncated negative binomial, T-NB), and mixture models (zero-inflated Poisson, ZIP, and zero-inflated negative binomial, ZINB) were used to understand the factors that contributed most to the occurrence of depredation events that included a small proportion of whale damage. Of the six distribution forms used, only the ZIP and T-NB models performed adequately in describing depredation data, and the T-NB and ZINB models outperformed the ZIP models in bootstrap cross-validation estimates of prediction error. Candidate T-NB and ZINB model results showed that encounter probabilities were more strongly related to large-scale covariates (space, season) and that depredation counts were correlated with small-scale characteristics of the fishery (temperature, catch composition). Moreover, there was little evidence of historical trends in depredation rates. The results show that the factors contributing to most depredation events are those already controlled by ships' captains and, beyond novel technologies to repel sharks, there may be little more to do to reduce depredation loss in the fishery within current economic and operational constraints. Article in Journal/Newspaper Northwest Atlantic Oxford University Press ICES Journal of Marine Science 66 4 708 719 |
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Oxford University Press |
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croxfordunivpr |
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English |
description |
Abstract MacNeil, M. A., Carlson, J. K., and Beerkircher, L. R. 2009. Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic. – ICES Journal of Marine Science, 66: 708–719. A suite of modelling approaches was employed to analyse shark depredation rates from the US Atlantic pelagic longline fishery. As depredation events are relatively rare, there are a large number of zeroes in pelagic longline data and conventional generalized linear models (GLMs) may be ineffective as tools for statistical inference. GLMs (Poisson and negative binomial), two-part (delta-lognormal and truncated negative binomial, T-NB), and mixture models (zero-inflated Poisson, ZIP, and zero-inflated negative binomial, ZINB) were used to understand the factors that contributed most to the occurrence of depredation events that included a small proportion of whale damage. Of the six distribution forms used, only the ZIP and T-NB models performed adequately in describing depredation data, and the T-NB and ZINB models outperformed the ZIP models in bootstrap cross-validation estimates of prediction error. Candidate T-NB and ZINB model results showed that encounter probabilities were more strongly related to large-scale covariates (space, season) and that depredation counts were correlated with small-scale characteristics of the fishery (temperature, catch composition). Moreover, there was little evidence of historical trends in depredation rates. The results show that the factors contributing to most depredation events are those already controlled by ships' captains and, beyond novel technologies to repel sharks, there may be little more to do to reduce depredation loss in the fishery within current economic and operational constraints. |
format |
Article in Journal/Newspaper |
author |
MacNeil, M. Aaron Carlson, John K. Beerkircher, Lawrence R. |
spellingShingle |
MacNeil, M. Aaron Carlson, John K. Beerkircher, Lawrence R. Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
author_facet |
MacNeil, M. Aaron Carlson, John K. Beerkircher, Lawrence R. |
author_sort |
MacNeil, M. Aaron |
title |
Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
title_short |
Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
title_full |
Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
title_fullStr |
Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
title_full_unstemmed |
Shark depredation rates in pelagic longline fisheries: a case study from the Northwest Atlantic |
title_sort |
shark depredation rates in pelagic longline fisheries: a case study from the northwest atlantic |
publisher |
Oxford University Press (OUP) |
publishDate |
2009 |
url |
http://dx.doi.org/10.1093/icesjms/fsp022 http://academic.oup.com/icesjms/article-pdf/66/4/708/29132122/fsp022.pdf |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_source |
ICES Journal of Marine Science volume 66, issue 4, page 708-719 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1093/icesjms/fsp022 |
container_title |
ICES Journal of Marine Science |
container_volume |
66 |
container_issue |
4 |
container_start_page |
708 |
op_container_end_page |
719 |
_version_ |
1801380439342972928 |