Estimating Cetacean Maximal Weight by Maximal Length: Using the Length-weight Allometry

Abstract

The body weight is an important measure of body size and relates to various biological features, but extremely difficult to be measured for most cetaceans in field. An allometry model was used to approximate cetacean maximum body weight by maximum body length. Data on maximum body length and weight for 66 species of cetaceans, out of 87 current species, were collected from published literatures. Least-squared regression by general linear model on all cetaceans without factoring the difference from different life-history patterns shows a length-weight allometry analogous to terrestrial mammals, implying a convergent resolution meeting heat preservation in endotherms. Further factoring the likely difference from different life-history patterns, principal component analysis and discriminant analysis indicate four distinctive groups of length-weight allometries: migratory Mysticetes, Arctic/Antarctic living Mysticetes, large Ontocetes and small Odontocetes. The length-weight allometries we present in this study can become a feasible proxy to approximate population biomass for cetaceans in field, combining the technique of laser photometry that directly measures cetacean body length alive. This proxy can help to integrate the biomass perspectives, including cetaceans, preys and habitat productivity, into practical conservation and management measure.