Migration as a source of bias in the measurement of cephalopod growth
Theory predicts that, in a closed exploited population showing no sampling or other bias, the mean age of fish or squid between one sampling date and the next should increase by the time interval between samples. Age data, derived from statoliths, have been used to test the hypothesis that the effec...
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Language: | English |
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Cambridge University Press (CUP)
1994
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Online Access: | http://dx.doi.org/10.1017/s0954102094000283 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102094000283 |
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crcambridgeupr:10.1017/s0954102094000283 2024-03-03T08:39:27+00:00 Migration as a source of bias in the measurement of cephalopod growth Hatfield, Emma M.C. Rodhouse, Paul G. 1994 http://dx.doi.org/10.1017/s0954102094000283 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102094000283 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 6, issue 2, page 179-184 ISSN 0954-1020 1365-2079 Geology Ecology, Evolution, Behavior and Systematics Oceanography journal-article 1994 crcambridgeupr https://doi.org/10.1017/s0954102094000283 2024-02-08T08:43:25Z Theory predicts that, in a closed exploited population showing no sampling or other bias, the mean age of fish or squid between one sampling date and the next should increase by the time interval between samples. Age data, derived from statoliths, have been used to test the hypothesis that the effect of migration through an area where a population of Loligo gahi is sampled would be apparent as an increase in mean age per modal group of less than one day per daily time interval between samples. The data show that, in both females and males, the relationship between mean statolith increment number and elapsed time between samples is positive in some months and negative in others. The months in which the relationship between mean increment number and elapsed time is negative are similar to those months in which recruitment has previously been demonstrated to occur, in February, April/May and September for both females and males. Cohorts of squid remain available to the fishery from June–September (females) and February–May and June–July (males) thus allowing mean monthly growth rates of 0.4 mm d −1 for females and 0.7 mm d −1 for males to be calculated. The present study shows that putative age data derived from statoliths apparently demonstrate some sampling biases within a fishery and their effects on the measurement of growth. Migration through the sampled population is manifested by an increase in mean increment number of less than one per day between samples, and growth can only be assessed where the increase in mean increment number is not significantly different from the time elapsed between samples. Article in Journal/Newspaper Antarctic Science Cambridge University Press Antarctic Science 6 2 179 184 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Geology Ecology, Evolution, Behavior and Systematics Oceanography |
spellingShingle |
Geology Ecology, Evolution, Behavior and Systematics Oceanography Hatfield, Emma M.C. Rodhouse, Paul G. Migration as a source of bias in the measurement of cephalopod growth |
topic_facet |
Geology Ecology, Evolution, Behavior and Systematics Oceanography |
description |
Theory predicts that, in a closed exploited population showing no sampling or other bias, the mean age of fish or squid between one sampling date and the next should increase by the time interval between samples. Age data, derived from statoliths, have been used to test the hypothesis that the effect of migration through an area where a population of Loligo gahi is sampled would be apparent as an increase in mean age per modal group of less than one day per daily time interval between samples. The data show that, in both females and males, the relationship between mean statolith increment number and elapsed time between samples is positive in some months and negative in others. The months in which the relationship between mean increment number and elapsed time is negative are similar to those months in which recruitment has previously been demonstrated to occur, in February, April/May and September for both females and males. Cohorts of squid remain available to the fishery from June–September (females) and February–May and June–July (males) thus allowing mean monthly growth rates of 0.4 mm d −1 for females and 0.7 mm d −1 for males to be calculated. The present study shows that putative age data derived from statoliths apparently demonstrate some sampling biases within a fishery and their effects on the measurement of growth. Migration through the sampled population is manifested by an increase in mean increment number of less than one per day between samples, and growth can only be assessed where the increase in mean increment number is not significantly different from the time elapsed between samples. |
format |
Article in Journal/Newspaper |
author |
Hatfield, Emma M.C. Rodhouse, Paul G. |
author_facet |
Hatfield, Emma M.C. Rodhouse, Paul G. |
author_sort |
Hatfield, Emma M.C. |
title |
Migration as a source of bias in the measurement of cephalopod growth |
title_short |
Migration as a source of bias in the measurement of cephalopod growth |
title_full |
Migration as a source of bias in the measurement of cephalopod growth |
title_fullStr |
Migration as a source of bias in the measurement of cephalopod growth |
title_full_unstemmed |
Migration as a source of bias in the measurement of cephalopod growth |
title_sort |
migration as a source of bias in the measurement of cephalopod growth |
publisher |
Cambridge University Press (CUP) |
publishDate |
1994 |
url |
http://dx.doi.org/10.1017/s0954102094000283 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102094000283 |
genre |
Antarctic Science |
genre_facet |
Antarctic Science |
op_source |
Antarctic Science volume 6, issue 2, page 179-184 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102094000283 |
container_title |
Antarctic Science |
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6 |
container_issue |
2 |
container_start_page |
179 |
op_container_end_page |
184 |
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1792495009137688576 |