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Shark Info   (06-15-1999)



Underwater Parks

Shark Info

  Main article:

Underwater Parks: Economic and Ecological Aspects

Shark Info

  Article 1:

Jeopardized ┬źNurseries┬╗

Dr. T. E. Hopkins

  Article 2:

Requiem for smoked dogfish

Dr. A. J. Godknecht

  Article 3:

Aggressive Sharks, reality or fantasy?

Dr. E. K. Ritter

  Fact Sheet:

Spiny Dogfish

Dr. E. K. Ritter

Requiem for smoked dogfish

By Dr. Alexander J. Godknecht

Spiny dogfish

The spiny dogfish (Squalus acanthias) is an endangered species and winds up on our plates as rolled strips of smoked dogfish and dogfish sides.

© Shark Info / J. Brümmer

The regular spiny dogfish, scientifically known as Squalus acanthias, is probably just as well- known to us as his larger relatives the white shark, the mako or the tiger shark. However, he is most likely better known under culinary synonyms such as "rolled strip of smoked dogfish" plain dogfish or as the fish found in "Fish & Chips" menus. On our menus it appears primarily as smoked, braised or cooked and few people realize that the fish on their plate is really shark meat. "Enjoy" your last strip of smoked dogfish since very soon our menus will be shortened by some lines and some fish dishes will disappear from our kitchen. Smoked dogfish strips will disappear like the dodo and the giant tortoise, for very soon we will have eaten their last remaining specimens.

Exploitation of spiny dogfish populations

Spiny dogfish populations have been exploited for many years. Those supplied for our kitchens have almost been exterminated in their European habitats, the eastern Atlantic, the North or East Sea, where they are more coincidental catches. The best spiny dogfish meat is imported from overseas. Fresh or frozen, the fish is transported by air, for example from the east coast of the U.S. or Canada. Germany alone imported an average of 1,700 tons of spiny dogfish annually until 1998. But this tonnage can be misleading and is shrinking at an alarming rate.

Deceptive tonnage

A constant catch quota is considered an indicator of intact populations. Many fishing authorities argue along these lines although in reality they really should know better. A certain tonnage always consists of individual fish and depends directly on their size and weight. From this point of view 1,700 tons are roughly equivalent to 740,000 spiny dogfish.

Until recently, fishers of spiny dogfish practiced selective fishing in the U.S., with the mesh size of their nets determining the size of the animals caught. This was the only way to satisfy market demands which dictate that a "real" spiny dogfish should weigh approximately 2.3 kilos and should measure about 83 cm in length (corresponding to an average-sized large, mature female).

Spiny dogfish

Fresh dogfish and rolled strips of smoked dogfish. Both will soon be an expensive rarity.

© Shark Info / J. Brümmer

But what happens when this size can no longer be delivered. Fishermen are not considered real fishermen unless they can satisfy demands, for essentially they live off the sale of their catches. Essentially, this means that you supply the market with smaller-sized fish. The consequences are disquieting. "...Previously, one dogfish side sufficed to make one smoked rolled strip, today it is often necessary to combine two sides in order to reach the required market size,..." complained Jens Brümmer of the fish smoking company G. F. Wendt GmbH in northern Germany. "...obviously this method cannot be used with the culinary dogfish, which means that smaller samples are being marketed.

The biological time bomb is ticking

If the number of average-sized sharks is reduced by about 20%, at least 185,000 more spiny dogfish must be caught to simply reach the 1,700 tons for the German market. The smaller the shark, the larger the quantity of catch must be, which in turn also means that more and more young and sexually immature animals will be caught. This is especially critical for spiny dogfish since sharks, in contrast to popular opinion, are not relatives of ordinary fish and their method of procreation is totally different. They do not bear thousands of young animals, but rather only two, four or perhaps ten youngsters, with a small number of species bearing 20 young. In addition, pregnancy and the time needed to reach sexual maturity is considerably longer. Unfortunately, the spiny dogfish is probably the worst off in this respect. A female spiny dogfish may give birth to about 20 pups, but these need 20 to 30 years to reach sexual maturity, and pregnancy itself lasts about 22 months (see bibliography in this issue's Fact Sheet). The probability is thus very high that an animal is caught even before it has had a chance to reproduce only once. Yet this "one-time bearing of young" is biologically one of the most important guarantees for species survival.

Much more serious is the effect of group behavior. In swarms, spiny dogfish swim mostly in separate groups of males and females. A single catch may thus effectively eliminate all sexually mature or all pregnant females. Today, it has already become very obvious that spiny dogfish have not only gotten smaller in size but have also been reduced in numbers. Man is literally scratching the bottom of the barrel. Up until April 1999 only a meager 57 tons of spiny dogfish were imported into Germany, 3% of previous average annual imports. This is not dictated by lack of demand, which is best indicated by prices, considering that high demand combined with a limited availability of raw materials will increase prices. In Germany alone, the first quarter of 1999 was marked by 25% higher prices for frozen dogfish. "...The rare quantity which reaches the market will soon turn into a rare and expensive commodity...", comments J. Brümmer.

Emergency measures

The hesitant reaction of U.S. authorities to these alarming signs is - as always - perhaps too late. Current plans foresee a 50% reduction of catch quotas for spiny dogfish in U.S. territorial waters, meaning from 20,000 to 10,000 tons annually. A further step would totally forbid direct fishing. However, this directive from the Department of Commerce will not go into effect before November 2000, besides being vehemently fought by various interest groups. Only the future will reveal if the emergency brake was pulled in time.

Meanwhile, the future looks dismal for spiny dogfish.

Shark Info Shark Info is grateful to Jens Brümmer from the fish smoking firm G.F. Wendt GmbH in northern Germany for all his help in obtaining research data and spiny dogfish photos.

* Dr. Alexander J. Godknecht is a biologist and President of the Shark Foundation. He is also a member of the Shark Info editorial team and works in the Zurich University Center for Computing Services.

May be published only by indicating the source: Shark Info / Dr. Alexander J. Godknecht



last change: 06-04-2016 11:48