Taxonomic identification of marine mammals –current research and approaches

The term ‘marine mammal’ includes members of 5 different mammalian groups: cetaceans (whales, dolphins, and porpoises), sirenians (manatees and the dugong), pinnipeds (sea lions, the walrus, and seals), marine and sea otters, and the polar bear. They are warm-blooded animals which have undergone major adaptations that permit them to live in water. These involve the loss of hind limbs (cetaceans and sirenians), the adaptation of limbs for propulsion through water (pinnipeds), and the general streamlining of the body for hydrodynamic efficiency (all 3 groups). Structural modifications to the sea otters and the polar bear are less apparent in body form and they continue to closely resemble their terrestrial counterparts. While cetaceans and sirenians spend their entire lives in the water, other marine mammals come ashore for various reasons, at particular times in their life cycle. In recent years, there has been a marked rise in the number of wildlife enthusiasts taking to educational and adventure expeditions to see marine mammals up close in their natural habitats. There is also increasing awareness of the integral importance of marine mammals to healthy aquatic ecosystems, and of the growing threats that a variety of anthropogenic activities, such as destruction of habitats, fishery interactions (e.g. gill net fishery), illegal fishing methods and pollution which challenge these animals and their environments. Research and education programmes should understand and clearly communicate these threats and recommend appropriate actions needed to reduce or eliminate their impacts.