Morphological and morphometric sperm analysis of dwarf sperm whale (Kogia sima)

Abstract

Nowadays, an increase in the number of marine species at risk of extinction has been observed. Therefore, studies on the reproductive characteristics of these animals are essential. This animal is considered relatively rare, and there is scarce information regarding its reproductive biology and physiology. Thus, this study aims to describe the morphology and morphometry of sperm obtained from dwarf sperm whale. The material used in this work was collected during the necropsy of a dwarf sperm whale specimen. Thus, seminal samples were fixed and stained with panoptic stain. In morphometric analysis, the results obtained were: acrosome length of 0.83±0.01 μm, head length of 1.5±0.02 μm, intermediate part of 0.4±0.00 μm and total length of 27.3±0.51 μm. In terms of morphology, the defects observed were double head, heavily curled tail, abnormal small head, simply bent tail, piriform head, heavily bent tail and specimens within the normal range. In this context, the morphometric and morphological sperm analysis of Kogia sima described in this study can assist future studies regarding the reproductive physiology of these animals.