Shark Tagging

Shark Tagging


The TRCC has had a long history of studying these ancient predators, focusing especially on the members of the Lamnid family – which includes makos and great whites.  These highly specialized predators share a characteristic with the tunas – in that they are essentially warm-blooded, allowing them to maintain a high metabolic rate in a wide range of environmental conditions.


White Shark TaggingDSC_0043


Scientists have been studying white sharks at the Farallon Islands for more than 20 years, originally using visual observations and photography, and then using electronic tag technologies.  The sharks arrive each fall at the islands to feed on the seals and sea lions that haul out there. Seals have a thick blubber layer, providing a rich food source for white sharks. To tag the white sharks, researchers first attract the sharks using a seal-shaped floating decoy which is drifting behind a small boat. As the shark approaches, the decoy is drawn alongside the boat and the researcher attaches the tag to the shark as it swims by. The tag may remain attached for up to a year recording data about the depth, temperature and location. At a pre-programmed date, the tag is released from the shark and the data are transmitted via satellite back to the laboratory where they are analyzed. These studies have revealed that white sharks travel much more extensively that was previously imagined. White sharks from the Farallones routinely journey as far as the Hawaiian Islands and back in a single year. They also yielded another surprise, in that many white sharks spend a significant portion of the year in an area about halfway between Hawaii and the North American Continent, in what has come to be known as the “White Shark Café.” To date scientists have not determined whether white sharks go to the café to eat or find mates (or both). This is one of the many mysteries about this fascinating animal.


sharktiedownSalmon Shark Tagging


Researchers from the TRCC have been traveling to Prince William Sound, Alaska, since 1999 to tag salmon sharks.  To date over 100 salmon sharks have been tagged with a variety of different electronic tags.  We have learned that these are wide-ranging, highly mobile sharks, which exhibit regular migrations from the cold productive waters of Alaska and the Bering Sea to destinations as far south as Baja California and Hawaii.  The unique anatomical and physiological characteristics of the salmon shark allow it to elevate its body temperature and maintain its high level of activity even in very cold waters, allowing it to function as an important apex predator throughout its broad environmental range.