Behavioural ecology of fishermen and odontocetes in a depredation context

Many marine predator species feed on fish caught by fishers directly from the fishing gear. Known as depredation this interaction issue has substantial socio-economic consequences for fishermen and conservation implications for the wildlife. Costs for fishers include damages to the fishing gear and...

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Bibliographic Details
Main Author: Richard, Gaëtan
Other Authors: La Rochelle, Guinet, Christophe
Format: Thesis
Language:English
Published: 2018
Subjects:
geo
Online Access:http://www.theses.fr/2018LAROS018/document
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spelling fttriple:oai:gotriple.eu:10670/1.id1hyw 2023-05-15T17:03:40+02:00 Behavioural ecology of fishermen and odontocetes in a depredation context Écologie comportementale des pêcheurs et odontocètes dans un contexte de déprédation Richard, Gaëtan La Rochelle Guinet, Christophe 2018-11-23 http://www.theses.fr/2018LAROS018/document en eng 10670/1.id1hyw http://www.theses.fr/2018LAROS018/document Theses.fr Déprédation Palangre démersale Orques Cachalots Bio-logging Écologie comportementale humaine Acoustique passive Demersal longline Killer whale Sperm whale Human behavioural ecology Passive acoustic monitoring envir geo Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2018 fttriple 2023-01-22T18:46:16Z Many marine predator species feed on fish caught by fishers directly from the fishing gear. Known as depredation this interaction issue has substantial socio-economic consequences for fishermen and conservation implications for the wildlife. Costs for fishers include damages to the fishing gear and increased fishing effort to complete quotas. For marine predators, depredation increases risks of mortality (lethal retaliation from fishers or bycatch on the gear). Longline fisheries are the most impacted worldwide, primarily by odontocetes (toothed whales) depredation, urging the need for mitigation solutions to be developed. Most of studies assessing depredation have primarily relied on surface observation data, thus the way odontocetes interact with longlines underwater remains unclear. Besides, the way fishermen respond to depredation during fishing operations, or can influence their detectability to odontocetes, have been poorly investigated. This thesis therefore aimed at investigating these aspects through a passive acoustic monitoring, bio-logging and human ecology approaches, focusing on the French Patagonian toothfish (Dissostichus eleginoides) longline fisheries impacted by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). Firstly, this thesis reveals that captains behave as optimal foragers but with different personal perception of competition and fishing fulfilment. Some captains would thus be more likely to stay within a patch or to haul closest longline even in presence of competition, suggesting these captains would show higher interaction rates. Additionally, the propagation of vessels’ acoustics varied depending on the type of manoeuvre (e.g. going backward vs. forward). The way captains use their vessels to navigate may therefore influence their detectability and so their depredation level. Secondly, loggers deployed on both the longlines (accelerometers) and odontocetes (GPS-TDR) revealed that killer whales and sperm whales are able to depredate on longlines while soaking on ... Thesis Killer Whale Orca Orcinus orca Patagonian Toothfish Physeter macrocephalus Sperm whale toothed whales Killer whale Unknown Orques ENVELOPE(140.031,140.031,-66.669,-66.669)
institution Open Polar
collection Unknown
op_collection_id fttriple
language English
topic Déprédation
Palangre démersale
Orques
Cachalots
Bio-logging
Écologie comportementale humaine
Acoustique passive
Demersal longline
Killer whale
Sperm whale
Human behavioural ecology
Passive acoustic monitoring
envir
geo
spellingShingle Déprédation
Palangre démersale
Orques
Cachalots
Bio-logging
Écologie comportementale humaine
Acoustique passive
Demersal longline
Killer whale
Sperm whale
Human behavioural ecology
Passive acoustic monitoring
envir
geo
Richard, Gaëtan
Behavioural ecology of fishermen and odontocetes in a depredation context
topic_facet Déprédation
Palangre démersale
Orques
Cachalots
Bio-logging
Écologie comportementale humaine
Acoustique passive
Demersal longline
Killer whale
Sperm whale
Human behavioural ecology
Passive acoustic monitoring
envir
geo
description Many marine predator species feed on fish caught by fishers directly from the fishing gear. Known as depredation this interaction issue has substantial socio-economic consequences for fishermen and conservation implications for the wildlife. Costs for fishers include damages to the fishing gear and increased fishing effort to complete quotas. For marine predators, depredation increases risks of mortality (lethal retaliation from fishers or bycatch on the gear). Longline fisheries are the most impacted worldwide, primarily by odontocetes (toothed whales) depredation, urging the need for mitigation solutions to be developed. Most of studies assessing depredation have primarily relied on surface observation data, thus the way odontocetes interact with longlines underwater remains unclear. Besides, the way fishermen respond to depredation during fishing operations, or can influence their detectability to odontocetes, have been poorly investigated. This thesis therefore aimed at investigating these aspects through a passive acoustic monitoring, bio-logging and human ecology approaches, focusing on the French Patagonian toothfish (Dissostichus eleginoides) longline fisheries impacted by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). Firstly, this thesis reveals that captains behave as optimal foragers but with different personal perception of competition and fishing fulfilment. Some captains would thus be more likely to stay within a patch or to haul closest longline even in presence of competition, suggesting these captains would show higher interaction rates. Additionally, the propagation of vessels’ acoustics varied depending on the type of manoeuvre (e.g. going backward vs. forward). The way captains use their vessels to navigate may therefore influence their detectability and so their depredation level. Secondly, loggers deployed on both the longlines (accelerometers) and odontocetes (GPS-TDR) revealed that killer whales and sperm whales are able to depredate on longlines while soaking on ...
author2 La Rochelle
Guinet, Christophe
format Thesis
author Richard, Gaëtan
author_facet Richard, Gaëtan
author_sort Richard, Gaëtan
title Behavioural ecology of fishermen and odontocetes in a depredation context
title_short Behavioural ecology of fishermen and odontocetes in a depredation context
title_full Behavioural ecology of fishermen and odontocetes in a depredation context
title_fullStr Behavioural ecology of fishermen and odontocetes in a depredation context
title_full_unstemmed Behavioural ecology of fishermen and odontocetes in a depredation context
title_sort behavioural ecology of fishermen and odontocetes in a depredation context
publishDate 2018
url http://www.theses.fr/2018LAROS018/document
long_lat ENVELOPE(140.031,140.031,-66.669,-66.669)
geographic Orques
geographic_facet Orques
genre Killer Whale
Orca
Orcinus orca
Patagonian Toothfish
Physeter macrocephalus
Sperm whale
toothed whales
Killer whale
genre_facet Killer Whale
Orca
Orcinus orca
Patagonian Toothfish
Physeter macrocephalus
Sperm whale
toothed whales
Killer whale
op_source Theses.fr
op_relation 10670/1.id1hyw
http://www.theses.fr/2018LAROS018/document
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