Blue whales in the northern Indian Ocean are thought to be a subgroup of the pygmy blue whales (B. musculus spp.).
They possess a different acoustic call (Alling and Payne, unpublished) and are five metres shorter than their Antarctic counterparts.
Unlike blue whales in other ocean basins, they do not undertake poleward migrations to feed, but remain in low-latitude waters yearround with a part of their population remaining resident in Sri Lankan waters.
This population is at risk of ship strike, as prime blue whale habitat lies adjacent to some of the most heavily used shipping lanes in the world.
Yet at present, relatively little data is available on the ecology of blue whales in Sri Lankan waters. The aim of this paper is to quantify the diving and surfacing characteristics of this population of blue whales.
While we acknowledge that the use of telemetry is a necessary step to refine the results provided through this study, it represents the first attempt to quantify three important surfacing parameters which are essential to any attempts to estimate abundance of this potentially isolated population, and thereby assess its conservation status.