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Effect of Swimming Activity on Relative Weight and Body Composition of Juvenile Rainbow Trout
Author(s) -
Simpkins Darin G.,
Hubert Wayne A.,
Martinez del Rio Carlos,
Rule Daniel C.
Publication year - 2003
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(2003)023<0283:eosaor>2.0.co;2
Subject(s) - rainbow trout , juvenile , biology , trout , hatchery , fishery , composition (language) , zoology , fish <actinopterygii> , ecology , linguistics , philosophy
Fisheries managers often assess body condition using relative weight ( W r ) because it provides a comparative measure of fish plumpness among individuals and populations. However, it is not known whether the morphological information that W r summarizes reflects physiological measures, such as relative lipid reserves, in rainbow trout Oncorhynchus mykiss . The purpose of this study was to determine whether swimming activity affects either the W r or proximate body composition of juvenile (total length, 170–260 mm) rainbow trout. When rainbow trout from a hatchery were fed ad libitum for 147 d, inactive (no current) and active (15 cm/s current velocity) fish did not differ in W r . However, inactive rainbow trout maintained relatively constant lipid levels, whereas active fish declined in lipid content. Relative weight may provide a comparable measure of body form, but it is not an accurate index of lipid content between active and inactive rainbow trout fed an excess ration. For assessing the physiological condition of rainbow trout, measurement of proximate body composition appears to be more accurate than indices based on length and weight.