Age determination and growth of the pollan, Coregonus autumnalis pollan Thompson, of Lough Neagh, Northern Ireland
Scales from Lough Neagh pollan display a large number of checks, making age determination difficult. Sclerite counts showed that an annual check is formed on scales in May and a second accessory check in most young fish in October. The method of ageing from scales was supported by inspection of leng...
| Published in: | Journal of Fish Biology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1984
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/j.1095-8649.1984.tb04786.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1984.tb04786.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1984.tb04786.x |
| Summary: | Scales from Lough Neagh pollan display a large number of checks, making age determination difficult. Sclerite counts showed that an annual check is formed on scales in May and a second accessory check in most young fish in October. The method of ageing from scales was supported by inspection of length‐frequency plots and by following the growth of pollan in their first 2 years of life. The body‐scale relationship was curvilinear. Back‐calculation showed that pollan of both sexes attain a fork length of 29 cm in 5 years (1 ∞=28.9 cm; k = 0.65; l 0 = ‐0.06 year). There is no evidence that annual growth rates have changed since 1965. Possible environmental causes of scale check formation are discussed. |
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