Statolith development and age determination in the ommastrephid squid Illex illecebrosus (Lesueur, 1821)

Morris, Claude Conrad (1983) Statolith development and age determination in the ommastrephid squid Illex illecebrosus (Lesueur, 1821). Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (29MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The first complete developmental series of a cephalopod statolith with its various structures is described. A new method involving a tracing for viewing, counting and recording growth increments in invertebrate statoliths and vertebrate otoliths is detailed and used to determine a daily rate of increment formation in statoliths of young illex illecebrosus. The number of increments increases as a function of statolith length, as a function of dorsal mantle length (DML), and also increases over time. Statolith length increases as a function of DML and also increases over time. -- The larval condition is shown to progress past the rhynchoteuthion (7.5-8.5 mm DML) to 50-70 mm DML, based on a change in growth constant and retention of larval characteristics including the shape of the statolith. -- Statolith length is a more accurate and precise indicator of age of the animal than is the number of growth increments.

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