Another species endemic to the Hauraki Gulf
outer islands under threat
New Zealand is a hotspot for seabird
diversity. Similarly, Great Barrier and its wider islands including the
Mokohinau group have the highest diversity of breeding seabirds in the
Hauraki Gulf. Despite this, many of New Zealand’s seabirds have never
been studied; this may be due to the fact that the petrels (the main
kind of seabird in New Zealand) spend most of their time at sea and only
come to land to breed. Even then, many of them breed in burrows
underground so if you were to sail past a colony you might not even know
it was there.
On the 16th of August, a hui took place at
Motairehe Marae between seabird researchers, DOC and Ngâti Rehua.
Members of the wider Great Barrier community also attended. The
researchers came from a range of institutions including Auckland
Council, NIWA, Auckland University, DOC National Office and private
consultancies. The purpose of the hui was to share the seabird
researchers’ knowledge with Ngâti Rehua as much of the work they have
been undertaking since 2004 has been conducted on islands either owned
by or with close connection to tangata whenua.
Seabird research has most recently been
conducted on the Mokohinau Islands, Mahuki Island and the black petrel
research on Hirakîmatâ/Mt Hobson. Black petrels and gannets have had
transmitters attached to them to find out where they go. It turns out
that gannets on Mahuki will travel as far as Whangarei for a day’s
fishing! The black petrels are a little different. They migrate to South
America each year after they have finished breeding. The image shows
their eastward and westward migration routes. The darker areas show
where the birds spend more time, presumably feeding. Research on the
Mokohinau Islands has also involved acoustic research which involves
putting out recording devices for extended periods to see which birds
live there. This has the added intention of discovering the breeding
site of the elusive NZ storm petrel which was thought to be extinct
until it was rediscovered in 1987.
Sadly the black petrel research which has
been conducted since 1995 has identified that the population is
undergoing gradual decline. The main agent of decline is fisheries
by-catch, an interaction that is hard to manage from the mainland. With
such a long migration, it’s no wonder they are at risk at sea. What this
does emphasise however, is the importance of the survival of every chick
that hatches on Great Barrier as this is the only viable black petrel
population in the world.
Many thanks to Motairehe Marae for hosting
the event and providing a delicious lunch, to the Ngâti Rehua Trust
Board for supporting the event and to all those that participated and
contributed on the day.