International Journal of Zoology Studies (2018)


Cetaceans are an important component of marine biodiversity, as apex predators, cetacean abundance and distribution are key indicators of environmental status, such as food web integrity. Five species of cetacean have been recorded in recent history within the North Bay of Bengal of Ganjam coast. Many are widely dispersed oceanic species that are rarely seen and very difficult to monitor. As a result, this indicator is restricted to assessing species for which more robust data are available. The information originates primarily from opportunistic sightings and few washed ashore marine mammals have being reported. Several of these appear to be poorly documented in this area. In this study, four marine mammals, common Bottle nose dolphin (Tursiops aduncus), Hump back dolphins (Sousa chinensis), Porpoise (Neophocaena phocaenoides) Spinner dolphins (Stenella longirostris) were counted and found in the shallow water areas of the coast during high tides to collect food. Bottle nose dolphin had relatively good population in the southern part of the coast. But other two species-Porpoise and Spinner dolphin were very rare. This assessment considers information on abundance and distribution and, where possible, assesses the status of the following species: bottle nose dolphin, Humpback dolphin, harbour porpoise, spinner dolphin. Some human activities affect the abundance and distribution of cetaceans. Historically, no direct evidence has being found for removal of individuals by hunting that could severe effects on populations. Today, by-catch in fisheries is one of the major causes of mortality for small cetaceans. Other pressures such as chemical and noise pollution are known to affect individual animals, but the effects of these on populations are not yet well understood.