Salmon sharks don't have as fierce a reputation as their cousins, the great whites and mako sharks, because there aren't any confirmed attacks on humans. Like the whites and the makos, they're relatively warm-blooded -- their body temperatures are warmer than the surrounding water. In this shark family, salmon sharks have the hottest bods -- in water that's 36 degrees F (2 C), their bodies can be 61 degrees F (16 C!).

As you can see from the map, salmon sharks range widely throughout the North Pacific Ocean. We tag them in Alaska waters, where they hang out from spring through fall; then they wander along the coast, or head south. They eat salmon, herring, sablefish and squid. Salmon sharks are caught accidentally by commercial salmon fishermen, many of whom regard the sharks as a complete nuisance. The sharks mess up their nets, and they eat the salmon. Some people think the animals would also make a good fishery -- in Japan, their hearts turn into tasty sashimi. But each female produces only two to five pups every year or two, and that might be too few to sustain a fishery. We don't know enough about the fish to know if it's endangered: The World Conservation Union (IUCN) puts it in a "data deficient" category. Because it takes many years to mature, and doesn't have many pups, Alaska limits its catch to two sharks per person per year.

We've tagged salmon sharks with SPOT (smart position or temperature transmitting tag) and PAT (pop-up archival) tags. They help us profile the oceans, because they oscillate between the surface and deep water -- 500 feet. Since they often come to the surface, it makes sense to attach SPOT tags to their dorsal fins.

Conservation Science Institute: Salmon Sharks

Florida Museum of Natural History: Salmon Sharks

Wikipedia: Salmon Shark

• Tagging Salmon Sharks, February 2003
• Salmon Shark Journeys, October 2005