Status of Marine Mammals in Sri Lanka

A. D. Ilangakoon

Member, Cetacean Specialist Group of the IUCN Species Survival Commission

Sri Lanka’s territorial waters are rich in marine mammal fauna with high species richness and year round abundance. However, present knowledge about this diverse segment of mammalian fauna is very limited due to a lack of dedicated research on the subject. In the scientific literature, there are records of stranded whales and museum specimens from as far back as the 1889 (Fernando, 1912; Deraniyagala, 1960). In the mid-20th century interactions with fisheries are mentioned for the first time (Lantz and Gunasekera, 1955). The first scientific records of live cetaceans are documented only after about 1980 although travelers and historians have referred to whales in the waters around the island as far back as the 14th century. More recent research carried out in the last two decades have resulted in most of what is known about species diversity, threats and conservation issues. The occurrence and hunting of the dugong in Sri Lanka’s waters appears in the literature in the late 19th century (Haley, 1884; Nevill 1885) but there has been very little recent work done on this globally threatened species.

Taxonomic Classification for Species in Sri Lanka’s Waters:

Based on current taxonomy 28 species of marine mammals within the two Orders of Cetacea and Sirenia have been recorded from the waters around Sri Lanka. This species list is based on specimens obtained from strandings on the coastline (Deraniyagala, 1948, 1960, 1963, 1965b; Leatherwood and Reeves, 1989, Ilangakoon, 2002), specimens from the fisheries bycatch and direct take (Prematunga et. al., 1985; Leatherwood and Reeves 1989; Leatherwood, 1990, Dayaratna and Joseph, 1993; Ilangakoon, 1997, 2002; Ilangakoon et. al., 2000a, 200b) and sightings from offshore surveys (Leatherwood et. al. 1984; Alling, 1986; Alling et. al., 1991; Ilangakoon, 2000b, 2002; Anonymous, 2003). The list is by no means complete as a new species for our waters Mesoplodon densirostris (Blainville’s beaked whale) was identified as recently as 2002 (Ilangakoon, 2002; Ilangakoon, 2003).

Of the total of 28 species, 27 belong to the Order Cetacea, are placed within the two Suborders Mysticeti and Odontoceti and come under the six families of Balaenopteridae, Physeteridae, Kogiidae, Ziphiidae, Delphinidae and Phocoenidae. The single species in the Order Sirenia is the Dugong (Dugong dugon) belonging to the family Dugongidae.

Based on Paper presented at Workshop organized by Young Biologists' Association Sri Lanka and Ministry of Forestry and Natural Resources on December 2005 at University of Sri Jayewardenepura, Nugegoda