Spiny dogfish numbers rise; fishermen mad

Dogged

Posted: Wednesday, September 06, 2006

In recent years more Cook Inlet sport fishermen have returned to shore feeling dogged. Not by their fellow fishermen, their girlfriends or their mothers, but by a small shark.

Spiny dogfish, one of three sharks that frequent Cook Inlet waters, have flopped on board Cook Inlet sport fishing boats in greater numbers in recent years, with a big increase in 2003, according to sample data collected by the Alaska Department of Fish and Game.

Fish and Game began interviewing sport fishermen about dogfish catches in 1998 and found that in August of 1998, 21 percent of sport fishing boat trips in Cook Inlet caught one or more dogfish. By August 2005, however, 60 percent caught one or more dogfish.

“They’re not just imagining it,” said Scott Meyer, a Fish and Game fisheries biologist. “We’re definitely documenting higher rates of incidental catch in the sport fishery.”

That doesn’t necessarily mean dogfish abundance has spiked. In fact, the general life history strategy of the dogfish doesn’t lend itself to a big population increase at any time, said Ken Goldman, a Fish and Game commercial fisheries biologist.

“These fish live upwards of 80; females aren’t mature until they’re about 36; males aren’t mature till they’re somewhere around 20; and they have the longest known gestation of any vertebrate,” he said.

While an African elephant carries its young about 22 months before giving birth, the dogfish may carry its young for up to 24 months before it gives birth, he said.

Biologists have offered a second possible explanation as to why fishermen are reporting more dogfish catches.

“What we think is going on is that there has been a shift in the distribution of dogfish ... where they are in the ocean,” Meyer said. “They’ve moved into the central gulf, especially Cook Inlet to Prince William Sound.”

Dogfish are considered a major nuisance among sport fishermen who curse the small sharks when they steal bait and tangle fishing lines.

“It is a pretty serious nuisance,” Meyer said.

Using the data collected from interviews of sport fishermen since 1998, Meyer estimated fishermen caught approximately one dogfish per angling day in 2005 during August, the month in which dogfish tend to show up in peak numbers.

The problem has been worse near Seward, where fishermen have caught dogfish at a rate of more than four fish per angling day, he said.

But the dogfish catch is unevenly distributed, with most boat trips catching no dogfish or very few, and a minority of boat trips catching as many as 30.

“You might have 10 percent of the boats catching most of the dogfish,” he said. “But for them it’s hell when they really get into them and they gotta go through 10 spiny dogfish to get each halibut. When you’re in the dogfish you’re in the dogfish.”

According to the folklore on the Internet, the small shark is called a dogfish because it hangs out in packs, he said.

Mounting with frustration, many fishermen have asked Fish and Game how they plan to address the issue, but because there is almost no local demand for dogfish there is little the department can do, Meyer said.

Some people complain that the bag limit of one dogfish per day, or two per year is too low.

All sharks are under the same bag limit, which was determined in the late 1990s. At the time, dogfish numbers where much lower and the Board of Fish did not see any reason why the bag limit should not be the same for the slow-reproducing dogfish as it is for other sharks.

Fish and Game has said it would not oppose a proposal to increase the bag limit for dogfish, but Meyer says he doesn’t think increasing the bag limit will help.

“It’s not like the bag limit is constraining very many people,” he said. “There aren’t many people who want to keep more dogfish. Everybody wants somebody else to catch them.”

Meyer said he thinks the low demand can be explained by a deep prejudice rather than any foul flavor.

“The sharks, especially the dogfish have gotten a bum wrap, maybe because they’re a nuisance,” he said.

In other parts of the world, such as Europe and Asia, there’s a big market for dogfish, Goldman said.

“Anyone who’s been to England and has had fish and chips has had dogfish,” he said.

Fishermen who want to eat their own fresh-caught dogfish, should bleed and gut the fish right away since shark blood contains urea. While biologists puzzle over why more dogfish may have moved into the central gulf, it may be best to follow the advice, “If you can’t beat ‘em, eat ‘em.”

“It’s an average fish, nothing spectacular about the flavor, but it’s certainly not like oh god I can’t believe people eat that,” Goldman said.

In the meantime, the dogfish does not appear to pose any biological threats, despite some fishermen’s concerns over their impacts on halibut and salmon.

“People who see them as a nuisance also blame them for every ill you can think of,” Meyer said.

Meyer said he has seen no evidence suggesting the shark eats salmon or disrupts halibut populations. Diet studies have found that the small-mouthed shark feeds primarily on krill and small bait fish such as hooligan.



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