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Observer Classification of Live, Mechanically Damaged, and Dead Pink Salmon Eggs
Author(s) -
Carls M. G.,
Thedinga J. F.,
Thomas R. E.
Publication year - 2004
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 - 10.1577/03-008
Subject(s) - observer (physics) , fishery , biology , zoology , physics , quantum mechanics
The susceptibility of pink salmon Oncorhynchus gorbuscha eggs to mechanical damage (shock) was studied to test the ability of observers to discriminate among live, dead, and damaged eggs. In a series of six laboratory trials, the mean error rate in discrimination did not exceed 12% and was 3.5% or less in four of six trials. The most common error was misclassification of damaged eggs as live (≤9 ± 1% (mean ± SE)), an error that is irrelevant in field studies designed to determine the natural death rate. The second most common error was damaged eggs classified as dead (≤4.6 ± 1%) when observation times were 60 min or less; this was reduced to less than 0.5% when observations were limited to 12 min or less. Inexperienced observers were easily trained (within 1 h) to classify eggs. To accurately describe natural systems before sample disturbance, damaged and dead egg categories should not be combined when reporting data.