CORDOVA (AP) -- The number of sharks around Prince William Sound is multiplying at an unprecedented rate, according to marine biologists.
Lee Hulbert of the National Marine Fisheries Service said more salmon sharks and sleeper sharks are being caught in the area than ever. He speculated that hatchery production may be behind the increased presence of sharks.
''All those pinks are pretty good shark bait,'' he said.
Scientists are particularly surprised by the growing numbers of sleeper sharks in the area. Four of sleeper sharks were recently caught from one pollock boat alone, according to The Cordova Times. The catch is a biological jackpot for scientists.
''They are a great mystery,'' said Tom Kline of the Prince William Sound Science Center. ''Nobody really knows much about them.''
Kline studies tissue samples of the denizens of Prince William Sound to determine how they fit into the food chain. He previously had samples from only 13 sleeper sharks. The Fisheries Department of the Virginia Institute of Marine Science would probably like some shark parts, as well, Kline said.
Salmon sharks remain the predominant kind of shark in the Sound.
Hulbert, who grew up kayaking on the Sound and later fished commercially out of Cordova during the 1980s, has tagged 223 salmon sharks in the Port Gravina area in the past two years. On a calm day in July, he said, it is possible to count literally thousands of sharks in Port Gravina. And those are only the ones that can be seen from the air, he added. No one knows how many could be lurking below the surface.
But those are salmon sharks. Sleeper sharks are another matter altogether.
Sleeper sharks are a largely nonmigratory, deep-water species believed to often hug the bottom in deep water. They are big, running as long as 25 feet and weighing up to a ton. They don't have the pronounced dorsal fin that many other sharks sport and are said to be quite docile.
''Sort of like big seagoing slugs,'' Kline said.
Hulbert agreed. When brought on board, they seem nearly boneless and quiver like Jello, he said.
''I call them big tubs of goo,'' Hulbert said. ''They're very sluggish when you are bringing them up.''
But there are indications that they're not just big, docile sea creatures. Last summer, Hulbert opened one up that had nine whole salmon in its gullet, indicating the soft, slow-moving creatures can act with considerable aggression and speed. That theory seems to be supported by the fact that more than 20 percent of the sleeper sharks Hulbert took samples from last summer had marine mammal parts from porpoises and seals in their stomachs.
It's possible that the salmon eaten by the sleeper shark were already dead. To work on the answer to that question, Hulbert has radio-tagged more than 20 sleeper sharks to determine whether they indulge in vertical migration during the night, to get at live, healthy food sources.
© 2017. All Rights Reserved. | Contact Us