New Zealand Journal of Marine and Freshwater Research abstracts

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The fine structure of check rings in the otolith of the New Zealand orange roughy {Hoplostethus atlanticus)

R. W. GAULDIE

Fisheries Research Centre P. O. Box 297 Wellington, New Zealand

Abstract Heating otoliths of the orange roughy (Hoplostethus atlanticus; Trachichthyidae) by the break-and-burn method causes a crystal transformation from aragonite to calcite. However, the change does not affect the legibility of the check rings. Orange roughy otolith check rings fall into two classes: a diffuse deposit (that is not visible in the break-and-burn method, but may have an annual periodicity) and structural check rings (which appear as fine lines on the surface, but as dark bands in the body of the otolith). Structural check ring deposition is irregular, but fortuitous aggregations of structural check rings might be mistaken for conventional annual check rings.

Keywords orange roughy; Hoplostethus atlanticus; Trachichthyidae; aragonite; calcite; check ring; otolith

New Zealand Journal of Marine and Freshwater Research, 1987. Vol. 21: 267-274 0028-8330/87/2102-0267$2.50/0 © Crown copyright 1987 Received 4 March 1986; accepted 18 July 1986

PDF file of entire paper: medium quality (3365K); (scanned from paper original: notes about this process)

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