Validation of age determination in Notothenia coriiceps, by means of a tag-recapture experiment at potter cover, South Shetland Islands

Of 409 Notothenia coriiceps specimens tagged and released at Potter Cove, South Shetland Islands, in successive years from 1989 to 1992, 9 were recaptured at the same site after periods of 11-21 months. A comparison was carried out between the annuli found in scales removed before and after the period of liberty. In scales of those specimens recovered after 11-13 months, one extra annulus was laid down. The same analysis in one individual recovered after 21 months resulted in 2 extra closely spaced sclerites zones, which corresponded with an elapse of two winter seasons. The comparative analysis between scales taken at recapture and otolith cross sections of the same individual allowed a simultaneous counting of the annuli with good agreement. These results validate the principle of annual deposition of the annulus in scales and otoliths of N. coriiceps. A preliminary analysis of scales regenerated after release indicates that these observations are of value in validation studies.