In February, we put a satellite tag on a striped marlin, a beautiful open-ocean predator that wanders through the tropical and temperate waters from the Indian to the Pacific oceans. During our summers and autumns, very large striped marlins – 150 (70 kg) to 440 pounds (200 kg) – linger around our New Zealand shores. This image of a foggy shore was taken off the west coast of the North Island.

It’s winter here now, and the striped marlin has moved on. This is where it was on its last report, halfway to South America, more than 3,000 miles from where we tagged it.

We’ve tagged 32 of these amazing fish since 2003, when fishing clubs, corporate sponsors, charitable foundations and the New Zealand Marine Research Foundation began working together to use satellite tags to help understand the behaviours of locally caught striped marlin in the context of their much broader distribution. That’s Peter Davie, one of the original scientists on the project who helped get the project off the ground. He’s now at Charles Sturt University in Australia.

In 2005, we New Zealand researchers at Blue Water Marine Research at Auckland University developed a method of successfully attaching SPOT tags to striped marlin tails, which for three successive seasons now have given exciting high resolution data on the fishes’ movements. We watched them swim from New Zealand to Fiji along the Colville-Lau Ridge, to New Caledonia, and Tonga.

Our tagging methods have come a long way in four seasons. In 2006 we successfully brought marlin on deck for tagging. That’s the first time we were able to measure the length of the fish – six to about eight feet (lower jaw fork length). In 2007, we tagged them in the water alongside a much smaller trailer boat. (The Ballyboy is one of the boats that participated in our 2005 efforts, and transferred a marlin to us for tagging.)

We are excited to see that it is possible to track striped marlin for longer than 3 months and 3,000 miles (5000 km) with the fish and tag still going strong as of June 2! Many of the marlin are double tagged with pop-off satellite tags as well, which have provided more valuable data about their diving behaviour and help give additional insights into the interplay between oceanography and where they go. We plan on tagging more later this year. Striped marlin tracks for the current season can be followed on TOPP's Live Access Server, which we scientists use to examine the relationship of the animal's journey and its environment -- the sea surface temperature and whether it's moving through or heading to areas where there's food.