Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland
In coastal Newfoundland, age 0 Atlantic cod (Gadus morhua) settle in shallow, nearshore regions occupied by older conspecifics. Although intercohort cannibalism is common, little is known of the behavioural responses that limit interactions among juvenile cohorts in the wild. We examined the day-nig...
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1998
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crcansciencepubl:10.1139/f97-291 2024-06-23T07:51:03+00:00 Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland Grant, Scott M Brown, Joseph A 1998 http://dx.doi.org/10.1139/f97-291 http://www.nrcresearchpress.com/doi/pdf/10.1139/f97-291 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 55, issue 6, page 1307-1316 ISSN 0706-652X 1205-7533 journal-article 1998 crcansciencepubl https://doi.org/10.1139/f97-291 2024-05-30T08:13:50Z In coastal Newfoundland, age 0 Atlantic cod (Gadus morhua) settle in shallow, nearshore regions occupied by older conspecifics. Although intercohort cannibalism is common, little is known of the behavioural responses that limit interactions among juvenile cohorts in the wild. We examined the day-night differences in catch and diet of age 0 and age 1 cod to delineate peak foraging activity and resource use in eelgrass (Zostera marina) habitat. Cod exhibited a size-related shift (age 0 to age 1) from feeding predominantly on zooplankton by day to benthos at night. Intercohort cannibalism occurred when age 1 cod were approximately three times larger than their prey. Concentrations of age 0 cod foraged in the water column during the day, ceased feeding at night, and appeared to disperse to the bottom. Seasonally decreasing daylength and prey size contributed to a decline in daily ration, yet age 0 cod still maintained a strict diurnal foraging cycle. The nocturnal decrease in feeding coincided with an increase in the catch of older conspecifics (age 2 and age 3) and increased foraging activity of age 1 cod, suggesting that avoidance of older conspecifics is an important factor influencing the diel foraging and activity cycles of age 0 cod. Article in Journal/Newspaper atlantic cod Gadus morhua Newfoundland Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences 55 6 1307 1316 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
description |
In coastal Newfoundland, age 0 Atlantic cod (Gadus morhua) settle in shallow, nearshore regions occupied by older conspecifics. Although intercohort cannibalism is common, little is known of the behavioural responses that limit interactions among juvenile cohorts in the wild. We examined the day-night differences in catch and diet of age 0 and age 1 cod to delineate peak foraging activity and resource use in eelgrass (Zostera marina) habitat. Cod exhibited a size-related shift (age 0 to age 1) from feeding predominantly on zooplankton by day to benthos at night. Intercohort cannibalism occurred when age 1 cod were approximately three times larger than their prey. Concentrations of age 0 cod foraged in the water column during the day, ceased feeding at night, and appeared to disperse to the bottom. Seasonally decreasing daylength and prey size contributed to a decline in daily ration, yet age 0 cod still maintained a strict diurnal foraging cycle. The nocturnal decrease in feeding coincided with an increase in the catch of older conspecifics (age 2 and age 3) and increased foraging activity of age 1 cod, suggesting that avoidance of older conspecifics is an important factor influencing the diel foraging and activity cycles of age 0 cod. |
format |
Article in Journal/Newspaper |
author |
Grant, Scott M Brown, Joseph A |
spellingShingle |
Grant, Scott M Brown, Joseph A Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
author_facet |
Grant, Scott M Brown, Joseph A |
author_sort |
Grant, Scott M |
title |
Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
title_short |
Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
title_full |
Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
title_fullStr |
Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
title_full_unstemmed |
Diel foraging cycles and interactions among juvenile Atlantic cod ( Gadus morhua) at a nearshore site in Newfoundland |
title_sort |
diel foraging cycles and interactions among juvenile atlantic cod ( gadus morhua) at a nearshore site in newfoundland |
publisher |
Canadian Science Publishing |
publishDate |
1998 |
url |
http://dx.doi.org/10.1139/f97-291 http://www.nrcresearchpress.com/doi/pdf/10.1139/f97-291 |
genre |
atlantic cod Gadus morhua Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 55, issue 6, page 1307-1316 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/f97-291 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
55 |
container_issue |
6 |
container_start_page |
1307 |
op_container_end_page |
1316 |
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1802642054532038656 |