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The effect of time from hatch on the yolk conversion efficiency of rainbow trout, Salmo gairdneri
Author(s) -
Hodson P. V.,
Blunt B. R.
Publication year - 1986
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.1095-8649.1986.tb04924.x
Subject(s) - salmo , rainbow trout , biology , zoology , yolk , dry weight , larva , yolk sac , trout , body weight , fishery , biomass (ecology) , weight gain , fish <actinopterygii> , ecology , embryo , endocrinology , botany
The growth and development of rainbow trout, Salmo gairdneri , from hatch to first feeding depends upon the nutrients stored in the yolk sac. The efficiency ( E ) with which yolk can be converted to larval biomass is a useful measurement in chronic toxicity tests, and it can be simply estimated by comparing the gain in larval weight ( L ) to the loss in yolk weight ( Y ) at hatch (time 0) and at any time t after hatch: E =( L 1 − L 0 )/( Y 0 − Y 1 ); E may be calculated on a wet or dry weight basis. Although the rates of weight change were constant for the first 15 days after hatch at 10.5° C, E was not. E increased from near 0 and approached a value of 2.1 on a wet weight basis or 0.70 on a dry weight basis after 5–8 days. The variability of E was also very high shortly after hatch, but declined and stabilized within 5–9 days. For toxicity testing, we recommend that E be measured 10–15 days post‐hatch to ensure precision with a minimum bias due to dissection error.