Statolith development and age determination in the ommastrephid squid Illex illecebrosus (Lesueur, 1821)
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 incr...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
1983
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| Online Access: | https://research.library.mun.ca/4113/ https://research.library.mun.ca/4113/1/Morris_ClaudeConrad.pdf https://research.library.mun.ca/4113/2/Morris_ClaudeConrad.pdf |
| Summary: | 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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