Age determination of eels, Anguilla anguilla (L): comparison of field data with otolith ring patterns

• Published in: Journal of Fish Biology
• Main Author: Berg, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1985
• Subjects: Anguilla anguilla
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1985.tb04294.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1985.tb04294.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1985.tb04294.x

Otoliths of eels recaptured up to 5 years after tagging were used for comparative work on the determination of annual ring patterns. It was possible to locate false annuli caused by the tagging procedure and subsequently to define annual rings in otoliths within the known period between first tagging and final catch. This determination gave an estimate of the size of the annual zones. Growth depression caused by tagging could be shown in cross sections of otoliths. Well defined annulus patterns in micrographs of otoliths from tagged eels were compared with otoliths from untagged eels. This comparison allowed a dimensional calibration of the ageing method and the recognition of misleading additional rings. Mean annual length increments of 47.88 mm and L x , of 123.3 mm were determined.