gh TOO MANY CRABS?

King crab (Paralithodes camtschatica) that is a source of light and delicious meat has successfully settled down in the Barents Sea. It was introduced into the new home 40 years ago, when Soviet scientists developed a special program for moving this native of the Far East closer to Europe. After delivering and releasing the crabs, this program sank into oblivion. The number of crabs was small at first, and it seemed that the experiment failed. However, within the last decade, crabs were often caught by fishing nets. Their population was monitored by specialists from the Knipovich Polar Research Institute for Sea Fishery. By 1997, the commercial reserve of crabs was estimated at 2-3 thousand animals, which is definitely insufficient for the fishery business. In the late 1990s, the crab population began to expand. First, it had become twice as large and, later, doubled again. It reached 1.5 million in 1999, and for a while the expansion slowed down. But, in 2002, the crabs multiplied again and doubled their population that now exceeds 3 millions. These developments make scientists worry about the consequences in case if the tendency persists, in particular, about the survival of other sea bottom inhabitants chased by hungry crabs. They are also concerned about reasons for the growth of the crab population.

Research assistant from the Laboratory of Commercial Invertebrates Igor Manushin comments this as follows. In fact, the given figures characterize the growth of the commercial population of crabs. Their total number in the Barents Sea has changed insignificantly. That is to say, only large-size crabs have become more numerous.

Are there any problems with food supply for them? By the present time, it seems that no. King crabs' menu is rather diverse. They eat worms, molluscs, and echinoderms, especially, starfishes that are quite abundant. Currently, crabs eat lots of fishery wastes, but not because of a drop in starfishes' numbers. This is certainly because of an increase in the biomass of capelin and the growing amount of its catch: the more is caught, the more is lost. Besides, many capelins die after spawning in spring and, thus, become a dinner for crabs.

Is there a competition for food between crabs and benthonic fishes? Igor Manushin again answers no. Crabs feed mainly on large-size starfishes that are uneatable for benthonic fishes. The latter prefer small-size starfishes, because they cannot bite, but just swallow these echinoderms at once. Therefore, the role of crab is in all senses positive: it makes no harm, but woks as a sea cleaner eating fishery wastes and dead fish.

So, crabs in the Barents Sea do not starve and grow at a normal rate. The only one thing that has diminished is the percentage of meat in their limbs. However, this is connected not with starving, but with warming of the Barents Sea. The temperature increase causes a shift of the molting season, and crabs have less time for growth prior to their catching.

It is expected that a regular catch of king crabs living in the Barents Sea will soon be practiced. Instead of doubts and worries about the fate of marine ecosystems Russian people will have a lot of crabs' meat. Although making a monster from crab is fashionable now, it definitely is an exaggeration.

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