According to Dr Krkosek: “Jackson et al. (2013) incorrectly lead the reader to a conclusion that sea lice play a minor, perhaps even negligible, role in salmon survival. Such a conclusion can be supported only if one is prepared to accept at least three fundamental methodological errors. The first is that the paired control–treatment structure of the data was not utilized in their meta-analysis (only as separate per trial chi-squared tests), thereby allowing inter annual fluctuations in overall survival among trials to obscure (or bias downward) the overall effects of parasiticide treatment relative to controls. The second is the use of arithmetic averages for comparing survival proportions between control and treatment groups; these data are log-normally distributed, and appropriate survival analysis involves the calculation of differences in groups on the log scale. Finally, their measurement of the difference in survival between control and treatment groups in absolute percentage points (their overall final result is approximately 1% point) does not equate to the percentage of salmon that are lost to mortality caused by parasites. Critically, as we show below,this last estimate is actually 30 times higher. nosalmonfarmsatsea/archives/799
Posted on: Sun, 18 Aug 2013 08:11:09 +0000
Trending Topics
Recently Viewed Topics
© 2015