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Age, growth and cohort composition of 0+ carp in the River Murray, Australia
Author(s) -
Vilizzi L.
Publication year - 1998
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1998.tb00599.x
Subject(s) - biology , otolith , carp , hatching , cyprinus , growth curve (statistics) , zoology , larva , cohort , fishery , ontogeny , characidae , fish <actinopterygii> , ecology , statistics , endocrinology , mathematics
The age, growth and cohort composition of young‐of‐the‐year (0+) carp, Cyprinus carpio from the River Murray in South Australia were investigated. Daily otolith microincrement formation was validated for the first 5 weeks of life in tetracycline‐marked, laboratory‐reared fish. Estimation of hatching dates from otolith microincrement counts corroborated the validation method and revealed two major peaks of spawning activity in October and in November. Two main cohorts of carp were distinguished, each consisting of several subcohorts showing variable growth rates. A simple linear regression and a logistic curve best described growth in length and weight, respectively, of wild larvae and juveniles. Two breakpoints, at 16·8 and 26·9 mm L s , were identified in the length—weight relationship, depending on the procedure followed in fitting a piecewise regression model to the log‐transformed variables. The insertion of an additional step of development in the larva period of the early ontogeny of carp is proposed.