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Shark Info 3 / 00   (09-15-2000)

Author

  Intro:

AES Conference in La Paz, Mexico

Shark Info

  Main article:

Whale Sharks: Central Theme of the AES Conference in La Paz, Mexico

Shark Info

  Article 1:

Managing Sharks and Their Relatives

Shark Info

  Article 2:

The cruel business with shark cartilage and cancer

Dr. A. J. Godknecht

  Article 3:

Is yet another South African marine ecosystem in danger?

Dr. E. K. Ritter

  Fact Sheet:

Whale Sharks

Dr. E. K. Ritter


Managing Sharks and Their Relatives

By Shark Info

The following article is based on a summary of the AFS Policy Statements titled Management of Sharks and their Relatives (Elasmobranchii) and is reprinted with the permission of J. A. Musick*, G. Burgess**, G. Cailliet***, M. Cahmi**** and S. Fordham*****.

Summary

Regional institutions in the U.S. must give high priority to the management of sharks and rays because these animals with their slow population growth rates are very susceptible to overfishing and hence collapse of their populations, according to a recommendation from the American Fisheries Society (AFS).

Initial Situation

Sharks and rays comprise approximately 1,000 species, whereby most of them have a slow growth rate, late sexual maturity and a low number of eggs or offspring. Such characteristics reflect a low increase in population size, combined with a strong susceptibility to every type of fishing. Managing their populations is thus indispensable, but unfortunately, the majority of the fisheries which have developed worldwide do not give this any consideration. In addition, many of the large-sized shark and ray species demonstrate very extensive migration behavior, making it just as imperative that national and international agreements are established to regulate their management.

Background History

Cetorhinus maximus

A basking shark (Cetorhinus maximus), the second-largest species of shark next to the whale shark.

© J. Stafford-Deitsch

Several cases of shark populations which collapsed because of intense fishing practices are well-documented, e.g. the mackerel shark (Lamna nasus) in the northern Atlantic, the soupfin shark (Galeorhinus galeus) in California and Australia, the basking shark (Cetorhinus maximus) and the spiny dogfish (Squalus acanthias) of the North Sea, and more recently the larger species living off the Eastern Coast of the U.S. The greatest threat appears to come from the mixed fishing industry which does not concentrate primarily on sharks or rays, but instead usually catches all types of fish species. To these fishermen it makes no difference if the sharks and rays caught have undergone noticeable population reductions because they are not targeted by these industries. An additional problem arises when sharks and rays are once found in statistics where they are not listed as single individuals but rather summarized under the category of "sharks" or "rays" so that strong changes in the respective populations can go on unnoticed. Several large shark and ray species have a population dynamic which more resembles that of whales or sea turtles. Both of the latter groups are widely recognized as endangered species and appropriate protective measures have been taken. Although some of the large-sized rays are also threatened by extinction, there is no corresponding international [Editor's note] regulation. Such a regulation is also nonexistent for threatened shark species such as the gray nurse sharks, dusky sharks and night sharks whose strong population decimations due to overfishing only recently made them candidates for the List of Endangered Species, as proposed by the National Marine Fisheries Service (NMFS, U.S. Department of Commerce).

Shark Fishing

Even the recognition that a species is in danger of extinction does not yet mean it will be protected accordingly from continuous overfishing. The dusky shark (Carcharchinus obscurus), for example, is a species with one of the slowest growth rates within the family of vertrebrates and late sexual maturity (20 years). In the past few years its populations have shown an 80-percent decline in the northwestern Atlantic. Still, even though this species is found on the respective lists, the animals can still be fished because legal regulations are not yet in force.

International discussions on the situation of sharks

Shortly, the FAO (Food and Agriculture Organization) also joined the discussion on the worldwide situation of shark populations and made appropriate suggestions for their management based on an initiative from CITES (Convention on International Trade in Endangered Species). A large part of the rapidly expanding shark fishery was stimulated by the finning industry. In the mid-80s the demand for shark fins, used mainly in soups, skyrocketed and their market value rose from one dollar per pound to more than 30 dollars upwards. The finning industry only lands the fins ("finning") and then throws the rest of the still living shark back into the ocean. Besides being wasteful, this method is also unethical and extremely cruel, not to mention being in sharp opposition to FAO recommendations. Some U.S. states and the fishing management plan of the NMFS for Atlantic sharks have now declared "finning" along the Atlantic coast and parts of the U.S. Pacific coast as illegal.

International Management

Shark species living near U.S. coastal regions of the Atlantic undertake extended migrations and swim to more southerly regions in the colder seasons. Species living in the open seas, e.g. the shortfin mako (Isurus oxyrhynchus) and the blue shark (Prionace glauca), even migrate across the entire Atlantic. It is thus logical that species which migrate beyond national boundaries need to be managed by means of bilateral and multilateral agreements.

Recommendations

The following suggestions stem partly from the AFS Policy Statement found in the Management of Sharks and their Relatives, supplied by courtesy of J. A. Musick et al.

Management: Due to the limited growth rates of many shark and ray species, high priority must be given to their management in order to prevent their populations from collapsing through overfishing. Fishing experts must pay special attention to shark and ray species who are less productive and are caught in the mixed fishing industry, and by doing so the managers must maintain the population's biomass above the level normally considered as sufficient.

Legal Regulations: Management means paying special attention that no young animals are overfished. Thus the appropriate quota regulations and size limits must be established and enforced in order to guarantee the survival of the necessary offspring. Management also should mean using the entire shark's body and "finning" as such should be generally prohibited on a worldwide basis [Editor's Note]. Living sharks should be released from hooks and set free, and the procedure embodied in an appropriate law.

Agreements: Multilateral agreements should be signed between fishing nations in connection with species which migrate long distances. The U.S. should retain its leading role in applying international recommendations, helping other nations to initiate local shark management plans through technical and financial support.

Scientific Research: Support must be given to research projects on fishing practices which reduce shark and ray bycatch and increase their survival rate following their release.

*

J. A. Musick is Manager of Vertebrate Ecology Programs and Systematics at VIMS (Virginia Institute of Marine Science), Gloucester Point, USA.

**

G. Burgess is Vice President of the IUCN/SSC Shark Specialist Group, Florida Museum, Gainesville

***

G. Cailliet is Professor at Moss Landing Marine Laboratories, California

****

M. Camhi is Assistant Manager of the IUCN/SSC Shark Specialist Group, Living Oceans Program, Islip, New York.

*****

S. Fordham is Project Manager, Fishing Industry, at the Center for Marine Conservation, Washington DC.

Additional Literature

    Musick, J. A. (1999). Ecology and conservation of long-lived marine animals. Page 1-10 in J. A. Musick, ed. Life in the slow lane: ecology and conservation of long-lived marine animals. Am. Fish. Soc. Symp. 23.

    Musick, J. A. (1999). Criteria to define extinction risk in marine fishes. The American Fisheries Society initiatives. Fisheries 24(12): 6-14.

Additional references on this subject can be obtained from the Shark Info Office.

May be published only by indicating the source: Shark Info / Shark Info



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