Investigating Preferred Prey and Habitat Use of Blue Whales from Sri Lankan Waters

Pygmy blue whales (Balaenoptera musculus brevicauda) are recorded year round off the coast of Sri Lanka, northern Indian Ocean. Photo ID studies indicate that a small population of 40-50 individuals are resident year round... [ view full abstract ]

Pygmy blue whales (Balaenoptera musculus brevicauda) are recorded year round off the coast of Sri Lanka, northern Indian Ocean. Photo ID studies indicate that a small population of 40-50 individuals are resident year round with other individuals occurring seasonally. The predominant behaviour recorded in the area is feeding. An analyses of 20 faecal samples, collected between 2014-2017, indicate that several species of prey may be important, including Meganyctiphanes spp., Stylocheiron spp. Euphausia spp. and Thysanoessa spp, which predominate at various depths but are concentrated over the 1000m isobar. A major shipping lane also traverses the 1000m isobar and whales are often seen surfacing close to ships. The overlap of critical feeding habitat with a busy shipping lane has been highlighted as a cause for concern and risk of collisions between whales and ships should be mitigated.