Food consumption estimates of Barents Sea harp seals
The consumption of various prey species, required by the Barents Sea harp seal (Phoca groenlandica) stock in order to cover their energy demands, has been estimated by combining data on the energy density of prey species and on seasonal variations in the energy expenditure and body condition of the...
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Septentrio Academic Publishing
2004
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Online Access: | https://doi.org/10.7557/3.2968 https://doaj.org/article/b2b9592a13d84003ad38c1dfe3079a7f |
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ftdoajarticles:oai:doaj.org/article:b2b9592a13d84003ad38c1dfe3079a7f 2023-05-15T15:38:17+02:00 Food consumption estimates of Barents Sea harp seals Kjell T Nilssen Ole-Petter Pedersen Lars P Folkow Tore Haug 2004-05-01T00:00:00Z https://doi.org/10.7557/3.2968 https://doaj.org/article/b2b9592a13d84003ad38c1dfe3079a7f EN eng Septentrio Academic Publishing https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2968 https://doaj.org/toc/1560-2206 https://doaj.org/toc/2309-2491 1560-2206 2309-2491 doi:10.7557/3.2968 https://doaj.org/article/b2b9592a13d84003ad38c1dfe3079a7f NAMMCO Scientific Publications, Vol 2, Iss 0, Pp 9-27 (2004) harp seals Phoca groenlandica food consumption energy demand prey Barents Sea Ecology QH540-549.5 article 2004 ftdoajarticles https://doi.org/10.7557/3.2968 2022-12-31T16:32:22Z The consumption of various prey species, required by the Barents Sea harp seal (Phoca groenlandica) stock in order to cover their energy demands, has been estimated by combining data on the energy density of prey species and on seasonal variations in the energy expenditure and body condition of the seals. Data on diet composition and body condition were collected in the period 1990-1996 by sampling harp seals during different seasons, in various areas of the Barents Sea. All diet composition data were based on reconstructed prey biomass, and adjustments were made for differences in digestibility of crustaceans and fish. The number of seals representing different age and sex groups were calculated for the entire population, and the monthly food requirements were estimated. In 1998, the total Barents Sea harp seal stock was estimated to comprise 2.22 million seals based on a mean production of 301,000 pups. After adjustments for a pup mortality of 30% its total annual food consumption was estimated to be in the range of 3.35-5.05 million tonnes (depending on choice of input parameters). Assuming that there are seasonal changes in basal metabolic rate associated with changes in body mass, and that the field metabolic rate of the seals corresponded to two times their predicted basal metabolic rate, the annual food consumption of the Barents Sea harp seal stock was estimated. If capelin (Mallolus villosus) was assumed to be abundant, the annual total consumption was estimated to be 3.35 million tonnes, of which 1,223,800 tonnes were crustaceans, 807,800 tonnes were capelin, 605,300 tonnes were polar cod (Boreogadus saida), 212,400 tonnes were herring (Clupea harengus), 100,500 tonnes were cod (Gadus morhua) and 404,200 tonnes were "other fish". A very low capelin stock in the Barents Sea (as it was in the period 1993-1996) led to switches in seal diet composition, with increased consumption of polar cod (from ca. 16%-18 % to ca. 23%-25 % of total consumption), other gadoids (dominated by cod, but also including ... Article in Journal/Newspaper Barents Sea Boreogadus saida Gadus morhua Harp Seal Phoca groenlandica polar cod Directory of Open Access Journals: DOAJ Articles Barents Sea NAMMCO Scientific Publications 2 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
harp seals Phoca groenlandica food consumption energy demand prey Barents Sea Ecology QH540-549.5 |
spellingShingle |
harp seals Phoca groenlandica food consumption energy demand prey Barents Sea Ecology QH540-549.5 Kjell T Nilssen Ole-Petter Pedersen Lars P Folkow Tore Haug Food consumption estimates of Barents Sea harp seals |
topic_facet |
harp seals Phoca groenlandica food consumption energy demand prey Barents Sea Ecology QH540-549.5 |
description |
The consumption of various prey species, required by the Barents Sea harp seal (Phoca groenlandica) stock in order to cover their energy demands, has been estimated by combining data on the energy density of prey species and on seasonal variations in the energy expenditure and body condition of the seals. Data on diet composition and body condition were collected in the period 1990-1996 by sampling harp seals during different seasons, in various areas of the Barents Sea. All diet composition data were based on reconstructed prey biomass, and adjustments were made for differences in digestibility of crustaceans and fish. The number of seals representing different age and sex groups were calculated for the entire population, and the monthly food requirements were estimated. In 1998, the total Barents Sea harp seal stock was estimated to comprise 2.22 million seals based on a mean production of 301,000 pups. After adjustments for a pup mortality of 30% its total annual food consumption was estimated to be in the range of 3.35-5.05 million tonnes (depending on choice of input parameters). Assuming that there are seasonal changes in basal metabolic rate associated with changes in body mass, and that the field metabolic rate of the seals corresponded to two times their predicted basal metabolic rate, the annual food consumption of the Barents Sea harp seal stock was estimated. If capelin (Mallolus villosus) was assumed to be abundant, the annual total consumption was estimated to be 3.35 million tonnes, of which 1,223,800 tonnes were crustaceans, 807,800 tonnes were capelin, 605,300 tonnes were polar cod (Boreogadus saida), 212,400 tonnes were herring (Clupea harengus), 100,500 tonnes were cod (Gadus morhua) and 404,200 tonnes were "other fish". A very low capelin stock in the Barents Sea (as it was in the period 1993-1996) led to switches in seal diet composition, with increased consumption of polar cod (from ca. 16%-18 % to ca. 23%-25 % of total consumption), other gadoids (dominated by cod, but also including ... |
format |
Article in Journal/Newspaper |
author |
Kjell T Nilssen Ole-Petter Pedersen Lars P Folkow Tore Haug |
author_facet |
Kjell T Nilssen Ole-Petter Pedersen Lars P Folkow Tore Haug |
author_sort |
Kjell T Nilssen |
title |
Food consumption estimates of Barents Sea harp seals |
title_short |
Food consumption estimates of Barents Sea harp seals |
title_full |
Food consumption estimates of Barents Sea harp seals |
title_fullStr |
Food consumption estimates of Barents Sea harp seals |
title_full_unstemmed |
Food consumption estimates of Barents Sea harp seals |
title_sort |
food consumption estimates of barents sea harp seals |
publisher |
Septentrio Academic Publishing |
publishDate |
2004 |
url |
https://doi.org/10.7557/3.2968 https://doaj.org/article/b2b9592a13d84003ad38c1dfe3079a7f |
geographic |
Barents Sea |
geographic_facet |
Barents Sea |
genre |
Barents Sea Boreogadus saida Gadus morhua Harp Seal Phoca groenlandica polar cod |
genre_facet |
Barents Sea Boreogadus saida Gadus morhua Harp Seal Phoca groenlandica polar cod |
op_source |
NAMMCO Scientific Publications, Vol 2, Iss 0, Pp 9-27 (2004) |
op_relation |
https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2968 https://doaj.org/toc/1560-2206 https://doaj.org/toc/2309-2491 1560-2206 2309-2491 doi:10.7557/3.2968 https://doaj.org/article/b2b9592a13d84003ad38c1dfe3079a7f |
op_doi |
https://doi.org/10.7557/3.2968 |
container_title |
NAMMCO Scientific Publications |
container_volume |
2 |
container_start_page |
9 |
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1766369085858250752 |