Whale watch: All part of a cop's lot

An adult male cuvier's beaked whale discovered on 90 Mile Beach has signs of tooth marks from fighting other male whales and also cookie cutter shark bites. Photo / Supplied

For New Zealand's most northern cop, working the beat on 90 Mile Beach seems to turn up "better work stories" on a regular basis.

The latest work story for Houhora officer Simon Wihongi was the discovery of a dead cuvier's beaked whale, also known as goose-beaked whale, about 10km north of Huketere on Tuesday.

The officer had been helping the army on an exercise near Te Paki Stream when he was called back to Kaitaia. Travelling on 90 Mile Beach he came across the whale.

In July Mr Wihongi came across a decomposing humpback whale near the Waipapakauri ramp entry to the beach.

Yesterday Department of Conservation staff in Kaitaia had reports of a second whale, also thought to be a cuvier's beaked whale, at Scott Point at the northern end of 90 Mile Beach. Marine mammal specialist Anton Van Helden said the cuvier's beaked whale, Ziphius cavirostris, was one of the more common stranding beaked whales in New Zealand waters.

"They are one of the species that has been shown to be affected by mid-frequency Navy sonar that have been implicated as the probable cause of a atypical mass strandings of this species in other parts of the world."

However, in New Zealand there was no record of strandings of this species. If they did strand it was typical to involve either single individuals or mother and calf pairs. Cuvier's beaked whales live in all the oceans of the world and were one of the most commonly seen beaked whale species and grew up to 7m. Mr Van Helden said cuvier's beaked whales were deep divers and last year a piece of technology known as the D-Tag 9, created by Aucklander Mark Johnson, set a new deep diving record for the species, with one recorded diving to 2992m and the duration was 138 minutes.

The whale found north of Hukatere was covered in circular scars and had long scratches across its body. The round scars were the result of cookie cutter sharks, also known as cigar sharks.

To feed, the shark suctions itself onto its prey. Once it is attached, the cookie cutter spins its body, using the row of serrated teeth on its lower jaw to remove a plug of flesh - leaving behind a crater-like wound. The long scratches were the result of fighting with other male cuvier's beaked whales.

New Zealand is a remarkable place for beaked whales; of the 22 species recognised worldwide 13 species are recorded from New Zealand.