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Threats facing sharks

Overfishing driven by the demand for shark fins

Shark processing factory in Asia. Photo by Julie Andersen.
The demand for shark fin soup has driven rampant, often illegal over fishing of sharks. In 2006, Dr. Shelley Clarke’s analysis of shark fin markets in Hong Kong estimated that upwards of 73 million sharks are being killed each year for the shark fin trade.

The over-fishing of sharks driven by demand for Shark Fin Soup is the leading cause of the dramatic decline in shark populations around the world. One third of all pelagic sharks are threatened with extinction, and half of the shark species targeted by commercial fisheries are threatened. Many shark populations have declined dramatically over the past thirty years, some by as much as 99%.

Bycatch

Bycatch: sharks caught when other seafood is targetted. Photographed undercover, shown by permission from the photographer.
The term bycatch is usually used for fish caught unintentionally in a fishery while intending to catch other fish. Worldwide commercial fisheries discard and estimated 38.5 million tonnes of marine life, accounting for over 40% of the estimated total marine catch (DAVIES RWD, et al. Defining and estimating global marine fisheries bycatch. Marine Policy (2009), doi:10.1016/j.marpol.2009.01.003)

Most bycatch of sharks comes from oceanic fishing fleets that target valuable fish such as tuna, using thousands of baited hooks on miles of long-line. Until relatively recently, this shark 'bycatch' was considered a nuisance, and sharks were cut loose and allowed to swim away. However, as shark fins have become increasingly valuable, these fleets have little incentive to take measures to reduce shark bycatch. It’s much easier and more profitable for them to cut off the fins and throw back the rest of the shark.

An estimated 50 million sharks are caught unintentionally as bycatch in commercial fisheries every year. In addition to longlines, bottom trawling and gillnetting also produce large numbers of shark bycatch.

Sportfishing

Shark tournament. Photo by Todd Cameron
Most recreational fishermen are responsible and care about the health of the oceans.  Some sport fishermen in the US and some other countries, however, do target sharks with the following unsustainable and wasteful fishing practices:

-Killing sharks for fishing records

-Killing sharks for trophies, such as jaws and "live mounts"

-Kill shark tournaments 
that often target threatened shark species and pregnant females – all for a contest

-Killing any shark from a threatened shark species

-Irresponsible catch and release fishing that results in high mortality and unnecessary injury and stress to the animals.

It is estimated that recreational fishermen kill 5 million sharks each year.

Nutritional Supplements

Graphic Credit: Shane Finnerty
There are two shark products that are sold as nutritional supplements - Shark Cartilage and Shark Liver Oil.

Shark Cartilage is used as a remedy for arthritis and inflammation, and some companies claim that is has anti-cancer properties. More recently supplement companies have been marketing shark liver oil for its supposed immune enhancing and anti-cancer properties. The anti-cancer claims are not proven and are disputed by the American Cancer Society, the FDA, Sloan- Kettering, Johns Hopkins University, and other reputable organizations. There are no reputable scientific studies demonstrating that shark liver oil supplements have any affect on immune function.

Shark cartilage, as an ingredient in Chondroitin supplements, has been demonstrated to be effective as an anti-inflammatory agent. Cartilage from other sources, such as cows, however, is just as effective. Cows are bred and raised commercially for their meat and various other products. And some plant-based alternatives have also been demonstrated to yield superior benefits. There is no justification, therefore, to hunt wild animals that are already severely depleted and over fished, when sustainable and equally effective alternatives are readily available.

Much of the damage was done by claims made in the book titled, "Sharks Don't Cancer" by William Lane. The book claimed that sharks don't get cancer and therefore taking shark cartilage pills will help to cure cancer in humans. Sharks do get cancer and the claims are ludicrous, but still the book received a huge amount of media attention. In 2000, however, the FTC ordered two companies to cease selling shark cartilage as a cure for cancer, and fined Lane Labs-USA, Inc. one million US dollars for false advertising in connection with shark cartilage sales. Yet still the myth continues. Most people have heard the false information that "sharks don't get cancer", but many fewer people know the truth.

Cosmetics

Deepwater sharks. Photographed undercover, shown by permission from the photographer.
Endangered deep water sharks are targeted and killed for their liver oil.

Squalene is a product derived from shark liver oil that is used in many cosmetic products. The oil is effective as a moisturizer, as is any oil, but it does not offer any advantages over sustainable plant based alternatives. Many of the sharks targeted for their liver oil are threatened species.

Habitat Loss, Pollution, Environmental degradation

Many sharks give birth to their pups in estuaries and coastal mangrove areas. The neonates stay in these relatively protected areas to avoid predation until they’re large enough to survive in the open ocean. When these areas are destroyed to accommodate coastal development and polluted, these shark populations can be severely impacted.

Additionally, sharks are very susceptible to other forms of pollution and environmental contamination. As apex predators they accumulate all the pollutants and toxins consumed and absorbed by organisms lower in the food chain.

Souvenirs

Shark jaws. Photo by Julie Andersen
In some parts of the world, including the United States, recreational fishermen target large sharks to make a trophy from the jaws. Since the meat from these large sharks is not edible, they often dump the rest of the shark back into the ocean. In other places, such as Mexico, souvenir jaws from all sizes and types of sharks, including baby sharks, can be found in tourist shops.

Shark Nets

Ragged tooth shark killed in a shark net. Photo by Paul Wildman.
Shark nets have been installed in parts of Australia and South Africa and in Hong Kong. Australia and South Africa also use baited drum lines to catch and kill sharks near swimming areas. Except in the case of Hong Kong, these measures are not barriers to keep sharks away from swimmers, but rather are “culling” programs intended to reduce the number of sharks in the area.

In fact, 35 to 50% of the sharks caught in nets are caught swimming away from the beach.

Shark nets kill thousands of sharks every year, including whale sharks, and also kill thousands of turtles, rays, mantas, dolphins and whales.

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