Interpreting spotted dolphin age distributions
Previous work has determined the age distribution from a sample of spotted dolphins (Stenella attenuata) killed in the eastern Pacific tuna purse-seine fishery. In this paper we examine the usefulness of this age distribution for estimating natural mortality rates. The observed agedistribution has a deficiency of individuals from 5-15 years and cannot represent a stable age distribution. Sampling bias and errors in age interpretation are examined as possible causes of the "dip" in the observed age structure. Natural mortality rates are estimated for the 15+ age classes based on the assumption that these are sampled representatively. The resulting annual survival rate <D.82) is too low to allow population growth, given what is known about dolphin reproductive rates. (PDF contains 30 pages.)
Main Authors: | , |
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Format: | monograph biblioteca |
Language: | English |
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NOAA/National Marine Fisheries Service/Southwest Fisheries Science Center
1984
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Subjects: | Ecology, Conservation, Fisheries, Spotted dolphins, Stenella attenuata, seining, by catch, tuna fisheries, |
Online Access: | http://hdl.handle.net/1834/20264 |
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dig-aquadocs-1834-202642021-07-13T03:13:11Z Interpreting spotted dolphin age distributions Barlow, Jay Hohn, Aleta A. Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries Previous work has determined the age distribution from a sample of spotted dolphins (Stenella attenuata) killed in the eastern Pacific tuna purse-seine fishery. In this paper we examine the usefulness of this age distribution for estimating natural mortality rates. The observed agedistribution has a deficiency of individuals from 5-15 years and cannot represent a stable age distribution. Sampling bias and errors in age interpretation are examined as possible causes of the "dip" in the observed age structure. Natural mortality rates are estimated for the 15+ age classes based on the assumption that these are sampled representatively. The resulting annual survival rate <D.82) is too low to allow population growth, given what is known about dolphin reproductive rates. (PDF contains 30 pages.) 2021-06-24T15:20:26Z 2021-06-24T15:20:26Z 1984 monograph http://hdl.handle.net/1834/20264 en NOAA Technical Memorandum NMFS http://swfsc.noaa.gov/publications/TM/NOAA-TM-NMFS-SWFC-48.PDF application/pdf application/pdf NOAA/National Marine Fisheries Service/Southwest Fisheries Science Center La Jolla, CA http://aquaticcommons.org/id/eprint/2460 403 2011-09-29 19:05:25 2460 United States National Marine Fisheries Service |
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English |
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Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries |
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Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries Barlow, Jay Hohn, Aleta A. Interpreting spotted dolphin age distributions |
description |
Previous work has determined the age distribution from a sample of spotted dolphins (Stenella attenuata) killed in the eastern Pacific tuna purse-seine fishery. In this paper we examine the usefulness of this age distribution for estimating natural mortality rates. The observed agedistribution has a deficiency of individuals from 5-15 years and cannot represent a stable age distribution. Sampling bias and errors in age interpretation are examined as possible causes of the "dip" in the observed age structure. Natural mortality rates are estimated for the 15+ age classes based on the assumption that these are sampled representatively. The resulting annual survival rate <D.82) is too low to allow population growth, given what is known about dolphin reproductive rates. (PDF contains 30 pages.) |
format |
monograph |
topic_facet |
Ecology Conservation Fisheries Spotted dolphins Stenella attenuata seining by catch tuna fisheries |
author |
Barlow, Jay Hohn, Aleta A. |
author_facet |
Barlow, Jay Hohn, Aleta A. |
author_sort |
Barlow, Jay |
title |
Interpreting spotted dolphin age distributions |
title_short |
Interpreting spotted dolphin age distributions |
title_full |
Interpreting spotted dolphin age distributions |
title_fullStr |
Interpreting spotted dolphin age distributions |
title_full_unstemmed |
Interpreting spotted dolphin age distributions |
title_sort |
interpreting spotted dolphin age distributions |
publisher |
NOAA/National Marine Fisheries Service/Southwest Fisheries Science Center |
publishDate |
1984 |
url |
http://hdl.handle.net/1834/20264 |
work_keys_str_mv |
AT barlowjay interpretingspotteddolphinagedistributions AT hohnaletaa interpretingspotteddolphinagedistributions |
_version_ |
1756077340822077440 |