Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia
Experimental demersal gillnets and demersal longlines were deployed from research vessels on grounds of Mustelus antarcticus during 1973–76. Gillnet mesh-size had major effects on catch composition and catch rate, whereas gillnet hanging ratio, hook-size, hook shank-length and hook-spacing had minor...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.569.4311 2023-05-15T13:56:13+02:00 Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia Terence I. Walker Russell J. Hudson Anne S. Gason The Pennsylvania State University CiteSeerX Archives 2005 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.4311 http://journal.nafo.int/35/walker/24-walker.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.4311 http://journal.nafo.int/35/walker/24-walker.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://journal.nafo.int/35/walker/24-walker.pdf Key words Australia by-catch catch rates gillnet longline observers shark fishery text 2005 ftciteseerx 2016-01-08T12:24:57Z Experimental demersal gillnets and demersal longlines were deployed from research vessels on grounds of Mustelus antarcticus during 1973–76. Gillnet mesh-size had major effects on catch composition and catch rate, whereas gillnet hanging ratio, hook-size, hook shank-length and hook-spacing had minor effects. The gillnets and longlines were much more effective at catching chondrichthyans than teleosts, and catches of species of cephalopoda, bivalvia, gastropoda, mammalia, aves and reptilia were negligible. Any reduction in the present legal minimum mesh-size of 6 inch the shark fishery would markedly increase by-catch. In gillnets monitored by scientific observers aboard commercial vessels during 1998–01, the ratio of the number of chondrichthyan to teleost animals was ~24:1 in Bass Strait and ~5:1 in South Australia. In Bass Strait between 1973–76 and 1998–2001, the catch rate by 6 inch mesh gillnets of chondrichthyans declined by one-third, whereas a change in the catch rate of teleosts was not statistically detectable. Most of this decline is explained by reductions of 54 % by Cephaloscyllium laticeps and of 87 % by Galeorhinus galeus. The retained commercial catch was 74 % of the chondrichthyan animals and 58 % of the teleosts caught; only 3% of the chondrichthyans and 2 % of the teleosts were discarded dead. There are occasional interactions with protected species (marine mammals and Carcharodon carcharias). Text Antarc* antarcticus Unknown |
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collection |
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ftciteseerx |
language |
English |
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Key words Australia by-catch catch rates gillnet longline observers shark fishery |
spellingShingle |
Key words Australia by-catch catch rates gillnet longline observers shark fishery Terence I. Walker Russell J. Hudson Anne S. Gason Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
topic_facet |
Key words Australia by-catch catch rates gillnet longline observers shark fishery |
description |
Experimental demersal gillnets and demersal longlines were deployed from research vessels on grounds of Mustelus antarcticus during 1973–76. Gillnet mesh-size had major effects on catch composition and catch rate, whereas gillnet hanging ratio, hook-size, hook shank-length and hook-spacing had minor effects. The gillnets and longlines were much more effective at catching chondrichthyans than teleosts, and catches of species of cephalopoda, bivalvia, gastropoda, mammalia, aves and reptilia were negligible. Any reduction in the present legal minimum mesh-size of 6 inch the shark fishery would markedly increase by-catch. In gillnets monitored by scientific observers aboard commercial vessels during 1998–01, the ratio of the number of chondrichthyan to teleost animals was ~24:1 in Bass Strait and ~5:1 in South Australia. In Bass Strait between 1973–76 and 1998–2001, the catch rate by 6 inch mesh gillnets of chondrichthyans declined by one-third, whereas a change in the catch rate of teleosts was not statistically detectable. Most of this decline is explained by reductions of 54 % by Cephaloscyllium laticeps and of 87 % by Galeorhinus galeus. The retained commercial catch was 74 % of the chondrichthyan animals and 58 % of the teleosts caught; only 3% of the chondrichthyans and 2 % of the teleosts were discarded dead. There are occasional interactions with protected species (marine mammals and Carcharodon carcharias). |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Terence I. Walker Russell J. Hudson Anne S. Gason |
author_facet |
Terence I. Walker Russell J. Hudson Anne S. Gason |
author_sort |
Terence I. Walker |
title |
Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
title_short |
Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
title_full |
Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
title_fullStr |
Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
title_full_unstemmed |
Catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern Australia |
title_sort |
catch evaluation of target, by-product and bycatch species taken by gillnets and longlines in the shark fishery of south-eastern australia |
publishDate |
2005 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.4311 http://journal.nafo.int/35/walker/24-walker.pdf |
genre |
Antarc* antarcticus |
genre_facet |
Antarc* antarcticus |
op_source |
http://journal.nafo.int/35/walker/24-walker.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.4311 http://journal.nafo.int/35/walker/24-walker.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766263588914200576 |