Why Do We Need Sharks
Sharks have long been considered mindless monsters. But science paints a different picture of these predators
Sharks are a Keystone Species
“A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically”
Sharks in their ecosystems are considered a keystone species. This means that every part of the food web relies on those sharks’ presence. A decrease or loss in sharks in an area can drastically upset the balance of an ecosystem
Why Is An Unbalanced Ecosystem Bad?
A balanced ecosystem allows for healthy numbers of animals, high diversity of species and lower prevalence of diseases (as sick animals are usually predated on). A healthy ecosystem provides food for human consumption, which is very important for coastal communities that rely on fishing as both revenue and sustenance. Thriving ecosystems also support tourism, represent cultures and contribute to an overall healthy ocean.
Why are Sharks Leaving Ecosystems?
Sharks leave ecosystems for a variety of reasons, including
- Overfishing- When prey items are overfished, sharks will leave ecosystems to seek a constant food source elsewhere
- Shark fishing- Sharks are K-selected, meaning they are slow to reach a stage of reproduction, and when they do reproduce, they only give birth to a small amount of young. This means that when sharks are killed for fishing, the impact of losing that shark is much higher than losing an animal that has a high reproductive rate (r-selected).
- Unhealthy oceans- An area that is high in pollution/trash, fishing traffic, low in fish diversity or poor in water quality will result in a decrease in shark populations.
Why are Sharks in Trouble?
Bycatch refers to any animal caught unintentionally in a fishery. Many methods of commercial fishing use longlines, gill nets or bottom trawlers to catch specific fish, but in the process can catch turtles, seabirds and sharks. An estimated 50 million sharks are caught in bycatch every year. The sharks are either cut loose and disposed of or are finned for the shark fin trade and dumped overboard. Despite available means to decrease bycatch of sharks, the strong economic incentive to keep the fins reduces the likelihood of implementing these methods. Simple gear changes, such as switching from steel to nylon leaders, have demonstrated a reduction of shark bycatch while improving catch of ‘target’ species (Ward et al. 2007). New hook designs, weak or smart hooks, as well as new shark derrents and fishing methods could greatly reduce shark bycatch while also resulting in higher yields of target fish, saving time and money for the crews
Shark fins are one of the most expensive seafood products on the market. “Shark finning” refers to the process of removing fins from a live or dead shark for export to consumers. Because most of the shark is of little value, fins are usually removed before discarding the rest of the shark, either by dropping them back into the ocean to die or by bringing them ashore for processing or throwing away. Shark fins are used mostly for Shark Fin Soup, although some can be sold as tourist goods. Shark finning is a problem because the shark fin trade is large unregulated and underreported. Although laws do exist in some places to regulate trade, many countries are not reporting accurate shark finning numbers. It is estimated that 26-73 million sharks die every year from the shark fin trade, although these number are considered a low estimate.
Why Is This A Problem?
Sharks are slow to reach maturity, meaning it takes several years before they are capable of reproducing. Sharks also carry young for several months to a year before giving birth to relatively few young. This means that as shark populations are severely declined, wild sharks cannot keep up with the population decrease. And as shark populations decline worldwide, ecosystems are changing in response, resulting in declines and threats to both recreational and commercial fisheries.
Where is This Happening?
The biggest perpetrators of shark finning and participating in the trade are Hong Kong, Taiwan, Indonesia, Singapore, United Arab Emirates, India, Yemen, Japan, Spain and Malaysia. The explanations for their participation include cultural traditions, medicinal claims and bycatch during commercial fishing.
Some shark products are sold as nutritional supplements, claiming anti-cancer properties and other healthy-living promises. No health claims about shark products have been reputably studied or proven. Sharks are widely believed to be “immune” to cancer, further supporting false claims. However, it is now known that sharks do get cancer and do not have a method of getting rid of it. You can also find shark products (usually cartilage or shark liver oil) in food, cosmetics, medicine and more. It is rich in omega-3 fatty acids, important to beauty products and some supplements.
Are Shark Products Sold on Guam?
Do your part by NOT supporting businesses on Guam that support the shark fin or shark product trade
This trade is devastating our ocean and is causing severe impacts to our fisheries and tourism
Check labels carefully, and ask questions if you are unsure about a product or meal availble on a menu
Habitat Loss & Pollution
As people develop houses and business around coasts, pollution and runoff levels go up, resulting in a decline in environmental health. Because of sharks’ low reproductive rate and their use of coastal habitats, poor water quality in coastal habitats can cause a decline in shark populations in those areas. Sharks also absorb and accumulate contaminants in water, meaning that toxins and pollutants in the water will be absorbed and will continue to accumulate in a sharks’ tissues
As coral reefs are threatened by overfishing and pollution, populations of larger fish on reefs are in decline. As large fish are removed from the ecosystem, sharks begin to look for food on off-shore or isolated reefs. This loss of both sharks and large fish result in an overpopulation of smaller fish, which lowers reef fish diversity and contributes to unhealthy reefs.
Much of the large-scale threats to sharks come from commercial fisheries. However, due to the large decline in shark populations, recreational fishing also has a big impact on sharks. Although many fisherman catch-and-release sharks, there are some who catch them for trophies or tournaments. Recreational fishermen can also lose gear and dump gear in the ocean, which can ensnare sharks and other species
What Can We Do To Save Sharks?
It is up to us to help sharks (and the ocean) recover from human impacts. Visit our “Get Involved” section to learn what you can do to make a difference for Guam and the world.