How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries?
© 2018 Marine mammal depredation on fisheries (animals removing fish caught on fishing gear) is a worldwide issue involving socio-economic and ecological consequences. Longline fisheries are the most impacted by odontocete (toothed whales) depredation. While technological means have provided limited...
Main Authors: | , , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
2018
|
Subjects: | |
Online Access: | http://hdl.handle.net/10536/DRO/DU:30108935 https://figshare.com/articles/journal_contribution/How_do_fishing_practices_influence_sperm_whale_Physeter_macrocephalus_depredation_on_demersal_longline_fisheries_/20802634 |
id |
ftdeakinunifig:oai:figshare.com:article/20802634 |
---|---|
record_format |
openpolar |
spelling |
ftdeakinunifig:oai:figshare.com:article/20802634 2024-06-23T07:56:01+00:00 How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? A Janc G Richard C Guinet John Arnould MC Villanueva G Duhamel N Gasco P Tixier 2018-10-01T00:00:00Z http://hdl.handle.net/10536/DRO/DU:30108935 https://figshare.com/articles/journal_contribution/How_do_fishing_practices_influence_sperm_whale_Physeter_macrocephalus_depredation_on_demersal_longline_fisheries_/20802634 unknown http://hdl.handle.net/10536/DRO/DU:30108935 https://figshare.com/articles/journal_contribution/How_do_fishing_practices_influence_sperm_whale_Physeter_macrocephalus_depredation_on_demersal_longline_fisheries_/20802634 All Rights Reserved Fisheries sciences not elsewhere classified Ecology not elsewhere classified Environmental management not elsewhere classified Depredation Demersal longline Sperm whale Patagonian toothfish Fishing practices School of Life and Environmental Sciences Centre for Integrative Ecology 3005 Fisheries sciences 3103 Ecology Text Journal contribution 2018 ftdeakinunifig 2024-06-06T02:05:01Z © 2018 Marine mammal depredation on fisheries (animals removing fish caught on fishing gear) is a worldwide issue involving socio-economic and ecological consequences. Longline fisheries are the most impacted by odontocete (toothed whales) depredation. While technological means have provided limited efficacy in reducing depredation, this study examined the fishing practices influencing both the proportion of depredated longline sets and the amount of fish removed by whales. We used an 8-year dataset from the Patagonian toothfish (Dissostichus eleginoides) longline fisheries operating in Crozet and Kerguelen Economic Exclusive Zones (EEZs) (South Indian Ocean) and GLMMs to investigate sperm whale (Physeter macrocephalus) depredation. Sperm whale depredation occurred on 61% of 5260 sets in Crozet and 41% of 16,902 sets in Kerguelen, and resulted in minimum estimated toothfish losses of 702 tons and 2649 tons, respectively, in the two areas. The probability of depredation decreased in winter months, increased with depth fished and decreased when vessels travelled over distances of > 60 km from fishing grounds with encountering depredation. These findings suggest the natural spatio-temporal distribution of sperm whales and their ability to follow vessels over limited ranges influence the number of captured fish removals. The amount of depredated toothfish decreased with the speed at which longline sets were hauled and increased with the soaking time of sets suggesting that whales may depredate sets during both hauling and soaking operations. Together, these observations indicate that rates of depredation may be influenced by the conditions of fishing operations and could therefore be employed to implement strategies of avoidance in all fisheries facing similar depredation impacts. Article in Journal/Newspaper Patagonian Toothfish Physeter macrocephalus Sperm whale toothed whales DRO - Deakin Research Online Indian Kerguelen |
institution |
Open Polar |
collection |
DRO - Deakin Research Online |
op_collection_id |
ftdeakinunifig |
language |
unknown |
topic |
Fisheries sciences not elsewhere classified Ecology not elsewhere classified Environmental management not elsewhere classified Depredation Demersal longline Sperm whale Patagonian toothfish Fishing practices School of Life and Environmental Sciences Centre for Integrative Ecology 3005 Fisheries sciences 3103 Ecology |
spellingShingle |
Fisheries sciences not elsewhere classified Ecology not elsewhere classified Environmental management not elsewhere classified Depredation Demersal longline Sperm whale Patagonian toothfish Fishing practices School of Life and Environmental Sciences Centre for Integrative Ecology 3005 Fisheries sciences 3103 Ecology A Janc G Richard C Guinet John Arnould MC Villanueva G Duhamel N Gasco P Tixier How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
topic_facet |
Fisheries sciences not elsewhere classified Ecology not elsewhere classified Environmental management not elsewhere classified Depredation Demersal longline Sperm whale Patagonian toothfish Fishing practices School of Life and Environmental Sciences Centre for Integrative Ecology 3005 Fisheries sciences 3103 Ecology |
description |
© 2018 Marine mammal depredation on fisheries (animals removing fish caught on fishing gear) is a worldwide issue involving socio-economic and ecological consequences. Longline fisheries are the most impacted by odontocete (toothed whales) depredation. While technological means have provided limited efficacy in reducing depredation, this study examined the fishing practices influencing both the proportion of depredated longline sets and the amount of fish removed by whales. We used an 8-year dataset from the Patagonian toothfish (Dissostichus eleginoides) longline fisheries operating in Crozet and Kerguelen Economic Exclusive Zones (EEZs) (South Indian Ocean) and GLMMs to investigate sperm whale (Physeter macrocephalus) depredation. Sperm whale depredation occurred on 61% of 5260 sets in Crozet and 41% of 16,902 sets in Kerguelen, and resulted in minimum estimated toothfish losses of 702 tons and 2649 tons, respectively, in the two areas. The probability of depredation decreased in winter months, increased with depth fished and decreased when vessels travelled over distances of > 60 km from fishing grounds with encountering depredation. These findings suggest the natural spatio-temporal distribution of sperm whales and their ability to follow vessels over limited ranges influence the number of captured fish removals. The amount of depredated toothfish decreased with the speed at which longline sets were hauled and increased with the soaking time of sets suggesting that whales may depredate sets during both hauling and soaking operations. Together, these observations indicate that rates of depredation may be influenced by the conditions of fishing operations and could therefore be employed to implement strategies of avoidance in all fisheries facing similar depredation impacts. |
format |
Article in Journal/Newspaper |
author |
A Janc G Richard C Guinet John Arnould MC Villanueva G Duhamel N Gasco P Tixier |
author_facet |
A Janc G Richard C Guinet John Arnould MC Villanueva G Duhamel N Gasco P Tixier |
author_sort |
A Janc |
title |
How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
title_short |
How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
title_full |
How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
title_fullStr |
How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
title_full_unstemmed |
How do fishing practices influence sperm whale (Physeter macrocephalus) depredation on demersal longline fisheries? |
title_sort |
how do fishing practices influence sperm whale (physeter macrocephalus) depredation on demersal longline fisheries? |
publishDate |
2018 |
url |
http://hdl.handle.net/10536/DRO/DU:30108935 https://figshare.com/articles/journal_contribution/How_do_fishing_practices_influence_sperm_whale_Physeter_macrocephalus_depredation_on_demersal_longline_fisheries_/20802634 |
geographic |
Indian Kerguelen |
geographic_facet |
Indian Kerguelen |
genre |
Patagonian Toothfish Physeter macrocephalus Sperm whale toothed whales |
genre_facet |
Patagonian Toothfish Physeter macrocephalus Sperm whale toothed whales |
op_relation |
http://hdl.handle.net/10536/DRO/DU:30108935 https://figshare.com/articles/journal_contribution/How_do_fishing_practices_influence_sperm_whale_Physeter_macrocephalus_depredation_on_demersal_longline_fisheries_/20802634 |
op_rights |
All Rights Reserved |
_version_ |
1802648845895598080 |