Modification of the biological intercept model to account for ontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus)*

Hobbs, James A. and Bennett, William A. and Burton , Jessica and Baskerville-Bridges, Bradd (2007) Modification of the biological intercept model to account for ontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus)*. Fishery Bulletin, 105 (1), pp. 30-38.

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Abstract

We investigated age, growth, and ontogenetic effects on the proportionality of otolith size to fish size in laboratory-reared delta smelt (Hypomesus transpacificus) from the San Francisco Bay estuary. Delta smelt larvae were reared from hatching in laboratory mesocosms for 100 days. Otolith increments from known-age fish were enumerated to validate that growth increments were deposited daily and to validate the age of fish at first ring formation. Delta smelt were found to lay down daily ring increments; however, the first increment did not form until six days after hatching. The relationship between otolith size and fish size was not biased by age or growth-rate effects but did exhibit an interruption in linear growth owing to an ontogenetic shift at the postflexon stage. To back-calculate the size-at-age of individual fish, we modified the biological intercept (BI) model to account for ontogenetic changes in the otolith-size−fish-size relationship and compared the results to the time-varying growth model, as well as the modified Fry model. We found the modified BI model estimated more accurately the size-at-age from hatching to 100 days after hatching. Before back-calculating size-at-age with existing models, we recommend a critical evaluation of the effects that age, growth, and ontogeny can have on the otolith-size−fish-size relations

Item Type: Article
Title: Modification of the biological intercept model to account for ontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus)*
Personal Creator/Author:
CreatorsEmail
Hobbs, James A.
Bennett, William A.
Burton , Jessica
Baskerville-Bridges, Bradd
Refereed: Yes
Journal or Publication Title: Fishery Bulletin
Volume: 105
Number: 1
Page Range: pp. 30-38
Date: 2007
ISSN: 0090-0656
Issuing Agency: United States National Marine Fisheries Service
Subjects: Biology
Ecology
Fisheries
Item ID: 8903
Depositing User: Patti M. Marraro
Date Deposited: 18 Jun 2012 09:31
Last Modified: 02 Jan 2014 19:38
URI: http://aquaticcommons.org/id/eprint/8903

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