Organ weights of three dolphin species (Sousa chinensis, Tursiops aduncus and Delphinus capensis) from South Africa: implications for ecological adaptation?

Data from bycaught, but otherwise presumed healthy individuals can contribute important biological data on species of cetaceans that are lacking. This study utilises collected systematic necropsies performed between October 1970 and May 2010 142 Indo-Pacific humpback dolphins (Sousa chinensis), 607 bottlenose (Tursiops aduncus), 640 long-beaked common (Delphinus capensis) incidentally caught drowned in the shark nets off KwaZulu-Natal, South Africa. The aim this analysis was to: (1) determine average absolute relative organ weights for three taxa as baseline values later pathological examinations; (2) examine potential correlations with physiology ecology genera. Body length-weight relationships were described species, indicating S. chinensis is more robust than T. aduncus, D. capensis being smallest out taxa. Organ weights, a percentage total body weight examined delphinids. Organs included heart, lungs trachea, liver, kidneys, spleen, testes. Relative liver kidney significantly larger small-bodied, fast-swimming capensis, slower, coastal possibly reflecting differences activity patterns species. lung trachea not different Combined testes weight, combination information group size sexual dimorphism suggested monogamous or extreme polygynous (harem) mating system chinensis, frequent copulations sperm competition capensis. results present suggest sizes major organs genera reflection differing life histories ecologies examined.