Abstract:
Species diversity, seasonal variation and capture methods were examined,
in small cetacean catches and offshore sightings at the fishing sites
and adjacent waters of Beruwal a and Negombo, on the west coast of Sri
Lanka. from May to October 1994.
325 and 263 individual specimens of 12 and 9 species of small
cetaceans (Stenella longirostris, Stenella coeruleoalba; Stenella attenuata,
Tursiops truncatus, Grampus griseus, Peponocephala electra, Pseudora
crassidens, Feresa attenuata, Kogia breviceps, Kogia simus, Steno
bredanensis, Lagenodelphis hosei) were recorded in the landings at Beruwala
and Negombo respectively. Offshore sightings contained 114 and 565 individuals,
of two species (Stenella longirostris, Tursiops truncatusi off
Beruwala and Negombo respectively. Species diversity between sites was
not significantly different for the catch but was significant for sightings,
while diversity between catch and sightings at each site was significantly
different. Seasonal variation was observed in peak catches but there was no
clear seasonality for offshore sightings. Capture method did not differ significantly
between sites indicating increased harpooning.
Many species not sighted offshore were found in catches at both sites,
indicating even deep sea stocks of small cetaceans are exposed to threat by
fisheries. The finding that intentional harpooning is spreading both in area
and extent should be noted and investigated further.
