Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation
The harbour porpoise is one of the most common toothed whales in European waters, with a population of more than 600,000 individuals. Despite their numbers, porpoises are severely threatened by commercial fisheries – they frequently become entangled in gillnets intended for different fish species. W...
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ftoslouniv:oai:www.duo.uio.no:10852/101072 2023-05-15T16:33:25+02:00 Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation Moan, André 2023 http://hdl.handle.net/10852/101072 en eng Paper 1. Moan, A., Skern-Mauritzen, M., Vølstad, J. H., & Bjørge, A. (2020). Assessing the impact of fisheries-related mortality of harbour porpoise (Phocoena phocoena) caused by incidental bycatch in the dynamic Norwegian gillnet fisheries. ICES Journal of Marine Science, 77(7-8), 3039-3049. DOI:10.1093/icesjms/fsaa186. The article is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1093/icesjms/fsaa186 Paper 2. Moan, A. & Bjørge, A. (2023). Pingers reduce harbour porpoise bycatch in Norwegian gillnet fisheries, with little impact on day-to-day fishing operations. Fisheries Research 259, 106564. doi:10.1016/j.fishres.2022.106564. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.fishres.2022.106564 Paper 3. Moan, A., Langangen, Ø., Bjørge, A. (2022). Simulating harbour porpoise population dynamics in different scenarios of future fishing effort and bycatch mitigation measures. Ecological Modelling. Manuscript. To be published. The paper is not available in DUO awaiting publishing. https://doi.org/10.1093/icesjms/fsaa186 https://doi.org/10.1016/j.fishres.2022.106564 http://hdl.handle.net/10852/101072 Doctoral thesis Doktoravhandling 2023 ftoslouniv https://doi.org/10.1093/icesjms/fsaa18610.1016/j.fishres.2022.106564 2023-03-15T23:36:47Z The harbour porpoise is one of the most common toothed whales in European waters, with a population of more than 600,000 individuals. Despite their numbers, porpoises are severely threatened by commercial fisheries – they frequently become entangled in gillnets intended for different fish species. When a porpoise becomes bycaught in a gillnet, it suffocates and dies. Since porpoises are not the intended catch, this is called bycatch. This thesis deals with bycatches of harbour porpoises in Norwegian gillnet fisheries. By using fishery data from a sample of fishing vessels, bycatch was estimated to 2,675 porpoises per year. The thesis also includes interesting results from field trials with using acoustic alarms (pingers) on gillnets to deter porpoises away from the nets. These trials showed that bycatches in gillnets with pingers were reduced by 95% compared to ordinary gillnets. Simulation studies further showed that using pingers in selected fisheries can reduce the total bycatch mortality substantially, but that this may not be enough to prevent population declines. Altogether, the thesis makes an important contribution to the wider understanding of the status of harbour porpoises in European waters that is important for conservation efforts and policymaking to protect harbour porpoises in Europe. Doctoral or Postdoctoral Thesis Harbour porpoise toothed whales Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
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Open Polar |
collection |
Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
op_collection_id |
ftoslouniv |
language |
English |
description |
The harbour porpoise is one of the most common toothed whales in European waters, with a population of more than 600,000 individuals. Despite their numbers, porpoises are severely threatened by commercial fisheries – they frequently become entangled in gillnets intended for different fish species. When a porpoise becomes bycaught in a gillnet, it suffocates and dies. Since porpoises are not the intended catch, this is called bycatch. This thesis deals with bycatches of harbour porpoises in Norwegian gillnet fisheries. By using fishery data from a sample of fishing vessels, bycatch was estimated to 2,675 porpoises per year. The thesis also includes interesting results from field trials with using acoustic alarms (pingers) on gillnets to deter porpoises away from the nets. These trials showed that bycatches in gillnets with pingers were reduced by 95% compared to ordinary gillnets. Simulation studies further showed that using pingers in selected fisheries can reduce the total bycatch mortality substantially, but that this may not be enough to prevent population declines. Altogether, the thesis makes an important contribution to the wider understanding of the status of harbour porpoises in European waters that is important for conservation efforts and policymaking to protect harbour porpoises in Europe. |
format |
Doctoral or Postdoctoral Thesis |
author |
Moan, André |
spellingShingle |
Moan, André Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
author_facet |
Moan, André |
author_sort |
Moan, André |
title |
Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
title_short |
Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
title_full |
Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
title_fullStr |
Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
title_full_unstemmed |
Bycatches of harbour porpoises in Norwegian coastal gillnet fisheries: implications for management and conservation |
title_sort |
bycatches of harbour porpoises in norwegian coastal gillnet fisheries: implications for management and conservation |
publishDate |
2023 |
url |
http://hdl.handle.net/10852/101072 |
genre |
Harbour porpoise toothed whales |
genre_facet |
Harbour porpoise toothed whales |
op_relation |
Paper 1. Moan, A., Skern-Mauritzen, M., Vølstad, J. H., & Bjørge, A. (2020). Assessing the impact of fisheries-related mortality of harbour porpoise (Phocoena phocoena) caused by incidental bycatch in the dynamic Norwegian gillnet fisheries. ICES Journal of Marine Science, 77(7-8), 3039-3049. DOI:10.1093/icesjms/fsaa186. The article is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1093/icesjms/fsaa186 Paper 2. Moan, A. & Bjørge, A. (2023). Pingers reduce harbour porpoise bycatch in Norwegian gillnet fisheries, with little impact on day-to-day fishing operations. Fisheries Research 259, 106564. doi:10.1016/j.fishres.2022.106564. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.fishres.2022.106564 Paper 3. Moan, A., Langangen, Ø., Bjørge, A. (2022). Simulating harbour porpoise population dynamics in different scenarios of future fishing effort and bycatch mitigation measures. Ecological Modelling. Manuscript. To be published. The paper is not available in DUO awaiting publishing. https://doi.org/10.1093/icesjms/fsaa186 https://doi.org/10.1016/j.fishres.2022.106564 http://hdl.handle.net/10852/101072 |
op_doi |
https://doi.org/10.1093/icesjms/fsaa18610.1016/j.fishres.2022.106564 |
_version_ |
1766023116391186432 |