Russian red king crabs may threaten other seafood in Norway.

Some people call them Joe Stalin's crabs, but they weren't actually one of the Soviet dictator's crimes. Still, red king crabs from Russia sure are a pest in Norwegian waters, and they seem to keep spreading no matter how hard Russian and Norwegian boats try to fish them out.

The good news is that fishermen can make big bucks--well, crowns or rubles--off the red crabs. The bad news is that red kings themselves will eat practically anything, from cod larvae to other crabs-meaning, some say, that they could wipe out other fish and seafood if they can't be stopped.

The species is originally from the North Pacific around the Kamchatka peninsula and neighboring Alaskan waters. In 1960, seven years after Stalin died, Soviet scientists introduced the crabs to the Russian Barents Sea near the border with Norway in order to increase the yield from local fisheries.

These aren't the little creatures most people think about when they hear the word "crab." They can be really huge--up to six feet wide. They're really ugly, too, their shells covered with nasty-looking spikes and their mouths are complex like those of insects. There are believed to be ten million of them, and their ranks are said to be growing almost exponentially.

There are differences of opinion as to whether or not the red king crab invasion is really a threat to the environment. On one hand, Rasmus Hansson from WWF Norway believes that the crabs pose a significant threat. On the other hand, Lars Petter Oeye, a crab safari organizer, agrees that more crabs should be caught, but also that the crab threat is sometimes exaggerated.

"They don't belong here," Hanson said. "The biodiversity convention states specifically that introduced species is one of the four most important factors for species extermination in the world." He and local fishermen, if for different reasons, agree that the annual fishing quota of 300,000 crabs must be increased.

"Of course we should say it is an invasive species, and of course we don't know enough. But it's not like they're really destroying the bottom of the sea," scoffed Oeye. As a sort of compromise, Norway has drawn a line in the sea: west of the line, it has allowed a free-for-all to catch the crabs, which were bringing up to 600 crowns ($98.73) a kilo in Oslo last year. East of the line, Russian and Norwegian fishermen were limited to 3.3 million crabs for 2006.

There's another restriction, too: only males can be taken. Females have to be thrown back, although at 500,000 eggs a piece they're the mothers of a population explosion. One man on safari reported trying out the eggs: "They're lovely--less salty than caviar, somehow clean tasting," he reported.