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Does cyclicity of growth rate in rainbow trout exist?
Author(s) -
Noel O.,
Bail P.Y.
Publication year - 1997
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.1095-8649.1997.tb01518.x
Subject(s) - rainbow trout , biology , zoology , growth rate , acclimatization , photoperiodism , population , trout , fish <actinopterygii> , ecology , fishery , botany , mathematics , demography , geometry , sociology
Ninety rainbow trout Oncorhynchus mykiss were reared in three tanks ( n= 30), and their growth rate was monitored for 25 weeks. During the experiment, fish were fed ad libitum , and kept under simulated natural photoperiod and constant temperature (14 ± 1°C). Throughout the experiment, water quality (pH, O 2 , N‐NH 3 , N‐NH 4 , NO 2 ) was considered optimum. Two growth rate periods were observed on the population: first an acclimation period (weeks 1–5), followed by a period of general decrease in growth rate (weeks 5–25). This trend was modelled with a third‐order polynomial function. The autocorrelation analysis of the fluctuations revealed a cyclicity of the growth rate with a 4–5‐week period. This cyclicity was independent of the tanks and of the growth rate trend type (long‐ v . short‐term acclimation period). However, at the individual level, trends as well as short‐term fluctuations were heterogeneous and no clear cyclicity could be detected. The biological relevance of the population growth rate cyclicity and the apparent absence of similar individual fluctuations are discussed.