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Temperature Effects on Otolith Microstructure and Birth Month Estimation from Otolith Increment Patterns in Atlantic Menhaden
Author(s) -
Fitzhugh Gary R.,
Nixon Stephen W.,
Ahrenholz Dean W.,
Rice James A.
Publication year - 1997
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1997)126<0579:teooma>2.3.co;2
Subject(s) - otolith , fishery , menhaden , estimation , environmental science , biology , fish <actinopterygii> , economics , management , fish meal
We demonstrate temperature‐influenced increment spacing in the sagittal otoliths of juvenile Atlantic menhaden Brevoortia tyrannus reared at different temperatures and describe otolith increment patterns from wild juveniles born in different months. Tank‐reared individuals completed metamorphosis a month earlier at 25°C than at ambient temperatures (10–14°C). We identified several patterns from the sectioned otoliths, including reduced time to metamorphosis, faster transition to the juvenile stage, and increased increment spacing after onset of metamorphosis for those individuals exposed to warmer temperatures. For wild individuals that could be accurately aged, mean otolith increment spacing in the zone from 70 to 80 increments increased 1–2 μm for fish born in November and December to more than 3 μm for fish born in February. The increase in increment spacing is consistent with the arrival of individuals across seasonally warming temperatures in the estuary. A discriminant analysis based on otolith increment spacing and metamorphic patterns successfully classified birth month for 59–100% (65% overall) of Atlantic menhaden spawned between November–February. This approach is being developed ultimately to identify the birth month of wild Atlantic menhaden adults in order to test for differential survival among cohorts born in different months that recruit to the fishery.