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Evacuation Rates of Young Yellow Perch, Perca flavescens (Mitchill)
Author(s) -
Noble Richard L.
Publication year - 1973
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1973)102<759:eroyyp>2.0.co;2
Subject(s) - perch , fishery , biology , fish <actinopterygii>
Gastric evacuation of a single meal of zooplankters by young yellow perch was about half as fast as that of a similar meal under conditions of continuous feeding. Time for gastric evacuation of a single meal of 150 to 200 daphnids by 60‐mm perch at 15 C was 12 hours compared to only 6 hours for a similar meal under conditions of continuous feeding. Likewise, 30‐ to 40‐mm perch fed 10 daphnids at 22 C required 6.5 and 1.5 hours respectively for single and multiple meals. Longer evacuation times were required for larger initial meals when subsequent meals were fed to 30‐ to 40‐mm fish at 22 C. Median evacuation time for the first daphnid consumed was only 0.6 hour compared to 2.6 hours for the one‐hundredth daphnid. Evacuation time for continuously feeding fish increased with size of fish. Gastric evacuation time at 20 to 22 C increased from 0.6 hours for fish 17 to 19.5 mm long to over 3 hours for 45‐mm fish. Because of the effect of meal sequence on evacuation time, conventional methods of estimating digestion rate may be inadequate for fish which feed continuously.