Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics
Thesis (M.Sc.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references Fecundity-size-age relationships in Atlantic cod (Gadus morhua) for the late 1990s and early 2000s off Newfoundland and Labrador were compared with historical data and with similar relationships fr...
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ftmemorialunivdc:oai:collections.mun.ca:theses4/128814 2023-05-15T15:26:50+02:00 Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics Fudge, Susan B. (Susan Beth). Memorial University of Newfoundland. Dept. of Biology 2009 x, 94 leaves : ill., maps Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses4/id/128814 Eng eng Electronic Theses and Dissertations (9.41 MB) -- http://collections.mun.ca/PDFs/theses/Fudge_SusanB.pdf a2981453 http://collections.mun.ca/cdm/ref/collection/theses4/id/128814 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Atlantic cod--Fertility Atlantic cod--Reproduction Echo sounding in fishing Text 2009 ftmemorialunivdc 2015-08-06T19:22:36Z Thesis (M.Sc.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references Fecundity-size-age relationships in Atlantic cod (Gadus morhua) for the late 1990s and early 2000s off Newfoundland and Labrador were compared with historical data and with similar relationships from cod stocks in Icelandic and Norwegian waters and in the, Baltic and the North Seas. For southern Newfoundland stocks that have fared relatively well in the 1990s and early 2000s, fecundity-size relationships did not differ from historical norms, although age at maturity was lower. In the highly stressed northern stock off Labrador, however, age at maturity was much lower than historical norms or in southern stocks, and fecundity much higher in small and young fish. Mortality rates were higher in the northern fish. These changes are explored in the context of changed life histories and the potential for rebuilding in stressed gadoid stocks. -- For the behavioural component of the study, passive and active acoustic properties of an Atlantic cod spawning aggregation were observed at depths of 40-50 m at the Bar Haven grounds in Placentia Bay, Newfoundland in April 2003. Sounds recorded by hydrophone were identical to those recorded from captive spawning cod of the same stock, but heard less often. From a surface-mounted transducer (EK500; 38kHz), cod were observed to undertake relatively rapid periodic vertical migrations approximately half way to the surface (20-25 m) which resulted in the formation of cod columns. This work is the first to demonstrate the simultaneous incidence of cod sounding and vertical behaviours resulting in column formations during spawning. Text atlantic cod Gadus morhua Newfoundland studies University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) Newfoundland |
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Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
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ftmemorialunivdc |
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English |
topic |
Atlantic cod--Fertility Atlantic cod--Reproduction Echo sounding in fishing |
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Atlantic cod--Fertility Atlantic cod--Reproduction Echo sounding in fishing Fudge, Susan B. (Susan Beth). Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
topic_facet |
Atlantic cod--Fertility Atlantic cod--Reproduction Echo sounding in fishing |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references Fecundity-size-age relationships in Atlantic cod (Gadus morhua) for the late 1990s and early 2000s off Newfoundland and Labrador were compared with historical data and with similar relationships from cod stocks in Icelandic and Norwegian waters and in the, Baltic and the North Seas. For southern Newfoundland stocks that have fared relatively well in the 1990s and early 2000s, fecundity-size relationships did not differ from historical norms, although age at maturity was lower. In the highly stressed northern stock off Labrador, however, age at maturity was much lower than historical norms or in southern stocks, and fecundity much higher in small and young fish. Mortality rates were higher in the northern fish. These changes are explored in the context of changed life histories and the potential for rebuilding in stressed gadoid stocks. -- For the behavioural component of the study, passive and active acoustic properties of an Atlantic cod spawning aggregation were observed at depths of 40-50 m at the Bar Haven grounds in Placentia Bay, Newfoundland in April 2003. Sounds recorded by hydrophone were identical to those recorded from captive spawning cod of the same stock, but heard less often. From a surface-mounted transducer (EK500; 38kHz), cod were observed to undertake relatively rapid periodic vertical migrations approximately half way to the surface (20-25 m) which resulted in the formation of cod columns. This work is the first to demonstrate the simultaneous incidence of cod sounding and vertical behaviours resulting in column formations during spawning. |
author2 |
Memorial University of Newfoundland. Dept. of Biology |
format |
Text |
author |
Fudge, Susan B. (Susan Beth). |
author_facet |
Fudge, Susan B. (Susan Beth). |
author_sort |
Fudge, Susan B. (Susan Beth). |
title |
Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
title_short |
Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
title_full |
Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
title_fullStr |
Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
title_full_unstemmed |
Fecundity and reproductive behaviour of Atlantic cod (gadus morhua) using active and passive acoustics |
title_sort |
fecundity and reproductive behaviour of atlantic cod (gadus morhua) using active and passive acoustics |
publishDate |
2009 |
url |
http://collections.mun.ca/cdm/ref/collection/theses4/id/128814 |
geographic |
Newfoundland |
geographic_facet |
Newfoundland |
genre |
atlantic cod Gadus morhua Newfoundland studies University of Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland studies University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (9.41 MB) -- http://collections.mun.ca/PDFs/theses/Fudge_SusanB.pdf a2981453 http://collections.mun.ca/cdm/ref/collection/theses4/id/128814 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766357318550683648 |