Abstract

Given its ability to yield predictions for very diverse phenomena based only on two parameters – body size and temper-ature –, the Metabolic Theory of Ecology (MTE) has earned a prominent place among ecology’s efficient theories. In a seminal article, the leading proponents of MTE claimed that the theory was supported by evidence from a Pauly (1980) dataset on natural mortality, biomass, and environmental temperature for 175 fish stocks spanning tropical, temperate and polar locations. We demonstrate that the evidence presented by MTE’s proponents is flawed because it fails to account for the fact that Pauly re-estimated environmental temperatures for polar fish as ´physiologically effective temperatures´ to correct for their “abnormally” high natural (mass-corrected) mortalities, which on average turned out to be similar to (rather than lower than) the mortalities recorded for temperate fish. Failing to account for these modifications skews the coefficients from MTE regression models and wrongly validates predictions from the theory. It is important to point out these deficiencies given MTE’s broad appeal as a theoretical framework for applied ecological research. In a recent application, MTE was used to estimate biomass production rates of prey fish in a model of invasive Indo-Pacific lionfish predation in Bahamian reefs. It is shown that the MTE coefficients may lead to a drastic overestimation of prey fish mortality and productivity rates, leading to erroneous estimations of target densities for ecological control of lionfish stocks.

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