The rangers walking the beach tonight are part of a new monitoring effort, led by The Nature Conservancy, to gather information about the Western Pacific leatherbacks nesting in the Solomon Islands.

Mr Noll says the last few weeks have been substantially warmer than average across the country prompted by warm sea temperatures in the western Pacific fuelling northerly low pressure systems bringing warm air to New Zealand.

Eel larvae face a long journey from their spawning grounds in unknown parts of the Western Pacific Ocean to the freshwater rivers and streams of New Zealand where they spend most of their lives.

Dr Egan and her team will be studying the ear bones of glass eels to learn more about their spawning locations and larval oceanic movements. In this new project, migrating female eels will be tagged and their location communicated to satellites to help pinpoint their spawning grounds in the western Pacific Ocean.