Acoustical properties of fishing gear: possible relationships to baleen whale entrapment

The incidental entrapment in passive fishing gear of mysticetes, including the humpback whale Megaptera novaeangliae, is examined, with specific reference to the role of acoustics as a mechanism in perception. The acoustics of capelin traps and other common net types involved in entrapment are inves...

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Main Author: Todd, Sean Kevin
Format: Thesis
Language:English
Published: Memorial University of Newfoundland 1991
Subjects:
Online Access:https://research.library.mun.ca/5875/
https://research.library.mun.ca/5875/1/Todd_SeanKevin.pdf
https://research.library.mun.ca/5875/3/Todd_SeanKevin.pdf
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spelling ftmemorialuniv:oai:research.library.mun.ca:5875 2023-10-01T03:54:54+02:00 Acoustical properties of fishing gear: possible relationships to baleen whale entrapment Todd, Sean Kevin 1991 application/pdf https://research.library.mun.ca/5875/ https://research.library.mun.ca/5875/1/Todd_SeanKevin.pdf https://research.library.mun.ca/5875/3/Todd_SeanKevin.pdf en eng Memorial University of Newfoundland https://research.library.mun.ca/5875/1/Todd_SeanKevin.pdf https://research.library.mun.ca/5875/3/Todd_SeanKevin.pdf Todd, Sean Kevin <https://research.library.mun.ca/view/creator_az/Todd=3ASean_Kevin=3A=3A.html> (1991) Acoustical properties of fishing gear: possible relationships to baleen whale entrapment. Masters thesis, Memorial University of Newfoundland. thesis_license Thesis NonPeerReviewed 1991 ftmemorialuniv 2023-09-03T06:45:34Z The incidental entrapment in passive fishing gear of mysticetes, including the humpback whale Megaptera novaeangliae, is examined, with specific reference to the role of acoustics as a mechanism in perception. The acoustics of capelin traps and other common net types involved in entrapment are investigated. -- Many marine mammals, particularly humpback whales, are incidentally entrapped in fishing gear in Newfoundland and Labrador inshore waters. Explanations of these collisions are complex, and the fundamental question of how a whale perceives a net has yet to be answered. It is clear that the whale fails to detect the net in time to avoid it. It has been argued that the mechanism of sound remains as the most probable primary system of orientation to targets such as nets. -- The present state of knowledge on the use of sound by baleen whales is discussed, including the possibility that humpback whales might possess a crude form of echolocation. It is also shown that a potential exists for the use of sound as a passive navigation system. Thus while humpbacks might use sound for orientation purposes, their apparent failure to detect nets might result from the target being acoustically cryptic. -- The acoustics of a capelin (Mallotus villosus) trap are investigated. It was found that capelin trap mesh produces a wide band signal, which is significantly reduced in level once the trap is filled with capelin. Acoustic damping by schools of bait are discussed. -- Capelin trap mesh produces the strongest acoustic signal, while larger mesh sized cod (Gadus morhua ) trap mesh produces the least detectable signature. It is shown that net noise production can be correlated to the drag that a net imposes in a current. Differences in net acoustic signature are discussed in terms of anecdotal entrapment evidence; there is a negative correlation between probability of entrapment and the strength of acoustic signature of that net type. Thesis baleen whale baleen whales Gadus morhua Humpback Whale Megaptera novaeangliae Newfoundland Memorial University of Newfoundland: Research Repository Newfoundland
institution Open Polar
collection Memorial University of Newfoundland: Research Repository
op_collection_id ftmemorialuniv
language English
description The incidental entrapment in passive fishing gear of mysticetes, including the humpback whale Megaptera novaeangliae, is examined, with specific reference to the role of acoustics as a mechanism in perception. The acoustics of capelin traps and other common net types involved in entrapment are investigated. -- Many marine mammals, particularly humpback whales, are incidentally entrapped in fishing gear in Newfoundland and Labrador inshore waters. Explanations of these collisions are complex, and the fundamental question of how a whale perceives a net has yet to be answered. It is clear that the whale fails to detect the net in time to avoid it. It has been argued that the mechanism of sound remains as the most probable primary system of orientation to targets such as nets. -- The present state of knowledge on the use of sound by baleen whales is discussed, including the possibility that humpback whales might possess a crude form of echolocation. It is also shown that a potential exists for the use of sound as a passive navigation system. Thus while humpbacks might use sound for orientation purposes, their apparent failure to detect nets might result from the target being acoustically cryptic. -- The acoustics of a capelin (Mallotus villosus) trap are investigated. It was found that capelin trap mesh produces a wide band signal, which is significantly reduced in level once the trap is filled with capelin. Acoustic damping by schools of bait are discussed. -- Capelin trap mesh produces the strongest acoustic signal, while larger mesh sized cod (Gadus morhua ) trap mesh produces the least detectable signature. It is shown that net noise production can be correlated to the drag that a net imposes in a current. Differences in net acoustic signature are discussed in terms of anecdotal entrapment evidence; there is a negative correlation between probability of entrapment and the strength of acoustic signature of that net type.
format Thesis
author Todd, Sean Kevin
spellingShingle Todd, Sean Kevin
Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
author_facet Todd, Sean Kevin
author_sort Todd, Sean Kevin
title Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
title_short Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
title_full Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
title_fullStr Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
title_full_unstemmed Acoustical properties of fishing gear: possible relationships to baleen whale entrapment
title_sort acoustical properties of fishing gear: possible relationships to baleen whale entrapment
publisher Memorial University of Newfoundland
publishDate 1991
url https://research.library.mun.ca/5875/
https://research.library.mun.ca/5875/1/Todd_SeanKevin.pdf
https://research.library.mun.ca/5875/3/Todd_SeanKevin.pdf
geographic Newfoundland
geographic_facet Newfoundland
genre baleen whale
baleen whales
Gadus morhua
Humpback Whale
Megaptera novaeangliae
Newfoundland
genre_facet baleen whale
baleen whales
Gadus morhua
Humpback Whale
Megaptera novaeangliae
Newfoundland
op_relation https://research.library.mun.ca/5875/1/Todd_SeanKevin.pdf
https://research.library.mun.ca/5875/3/Todd_SeanKevin.pdf
Todd, Sean Kevin <https://research.library.mun.ca/view/creator_az/Todd=3ASean_Kevin=3A=3A.html> (1991) Acoustical properties of fishing gear: possible relationships to baleen whale entrapment. Masters thesis, Memorial University of Newfoundland.
op_rights thesis_license
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