Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints
New methods of estimating the size of salmonids Salmo spp. and eels Anguilla anguilla consumed by otters Lutra lutra are presented, based on feeding trials involving captive, tame otters. These methods involve modelling the size‐related differential recovery of key fish bones recovered in faeces (sp...
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Language: | English |
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Wiley
1996
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Online Access: | http://dx.doi.org/10.1111/j.1469-7998.1996.tb05397.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1469-7998.1996.tb05397.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x |
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crwiley:10.1111/j.1469-7998.1996.tb05397.x 2024-06-02T07:55:13+00:00 Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints Carss, D. N. Elston, D. A. 1996 http://dx.doi.org/10.1111/j.1469-7998.1996.tb05397.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1469-7998.1996.tb05397.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Zoology volume 238, issue 2, page 319-332 ISSN 0952-8369 1469-7998 journal-article 1996 crwiley https://doi.org/10.1111/j.1469-7998.1996.tb05397.x 2024-05-03T11:07:04Z New methods of estimating the size of salmonids Salmo spp. and eels Anguilla anguilla consumed by otters Lutra lutra are presented, based on feeding trials involving captive, tame otters. These methods involve modelling the size‐related differential recovery of key fish bones recovered in faeces (spraints) and avoid two sources of errors that may have occurred using previous techniques which relied solely on a series of correlations between fish length and the length of individual vertebrae. Sources of errors avoided are: (a) that vertebrae recovered in spraints could not always be assigned to the correct correlation equation for mean, maximum, or minimumsized bones; and (b) that the number of fish represented in a spraint was assumed to be one, in the case of similarly‐sized vertebrae, and two in the case of bones varying considerably in size. We tested the use of salmonid atlas vertebrae to determine the largest minimal numbers estimate, the length frequency distribution of salmonids consumed, and to estimate the proportions of trout and salmon in the diet. Eels do not contain an atlas which is resistant to digestion and so equivalent estimates of the minimum numbers of fish represented in spraints are not possible. A model was therefore developed to estimate the distribution of lengths of fish consumed from the lengths of thoracic vertebrae recovered in the spraints using a series of equations. For each type of prey (salmonids or eels), the proportions of identifiable bones recorded in spraints were related to the original size of ingested fish. Such models greatly enhance the value of otter spraint analyses, particularly for size‐selection studies. Article in Journal/Newspaper Anguilla anguilla Lutra lutra Wiley Online Library Journal of Zoology 238 2 319 332 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
New methods of estimating the size of salmonids Salmo spp. and eels Anguilla anguilla consumed by otters Lutra lutra are presented, based on feeding trials involving captive, tame otters. These methods involve modelling the size‐related differential recovery of key fish bones recovered in faeces (spraints) and avoid two sources of errors that may have occurred using previous techniques which relied solely on a series of correlations between fish length and the length of individual vertebrae. Sources of errors avoided are: (a) that vertebrae recovered in spraints could not always be assigned to the correct correlation equation for mean, maximum, or minimumsized bones; and (b) that the number of fish represented in a spraint was assumed to be one, in the case of similarly‐sized vertebrae, and two in the case of bones varying considerably in size. We tested the use of salmonid atlas vertebrae to determine the largest minimal numbers estimate, the length frequency distribution of salmonids consumed, and to estimate the proportions of trout and salmon in the diet. Eels do not contain an atlas which is resistant to digestion and so equivalent estimates of the minimum numbers of fish represented in spraints are not possible. A model was therefore developed to estimate the distribution of lengths of fish consumed from the lengths of thoracic vertebrae recovered in the spraints using a series of equations. For each type of prey (salmonids or eels), the proportions of identifiable bones recorded in spraints were related to the original size of ingested fish. Such models greatly enhance the value of otter spraint analyses, particularly for size‐selection studies. |
format |
Article in Journal/Newspaper |
author |
Carss, D. N. Elston, D. A. |
spellingShingle |
Carss, D. N. Elston, D. A. Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
author_facet |
Carss, D. N. Elston, D. A. |
author_sort |
Carss, D. N. |
title |
Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
title_short |
Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
title_full |
Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
title_fullStr |
Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
title_full_unstemmed |
Errors associated with otter Lutra lutra faecal analysis. II. Estimating prey size distribution from bones recovered in spraints |
title_sort |
errors associated with otter lutra lutra faecal analysis. ii. estimating prey size distribution from bones recovered in spraints |
publisher |
Wiley |
publishDate |
1996 |
url |
http://dx.doi.org/10.1111/j.1469-7998.1996.tb05397.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1469-7998.1996.tb05397.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1996.tb05397.x |
genre |
Anguilla anguilla Lutra lutra |
genre_facet |
Anguilla anguilla Lutra lutra |
op_source |
Journal of Zoology volume 238, issue 2, page 319-332 ISSN 0952-8369 1469-7998 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1469-7998.1996.tb05397.x |
container_title |
Journal of Zoology |
container_volume |
238 |
container_issue |
2 |
container_start_page |
319 |
op_container_end_page |
332 |
_version_ |
1800746991854026752 |