Why Are Sharks Important For Healthy Coral Reefs?
Sharks Keep Coral Reef Ecosystems In Balance
Sharks are top predators in aquatic environments, which means that they have few natural predators and prey on species below them in the food web. Sharks restrict the abundance of their prey, which then impacts the prey of these species, and so on, in the food web. Since sharks actively or indirectly impact all layers of the food chain, they help to sustain the structure of balanced ocean habitats.
Sharks are vital ecologically, they help maintain healthy marine ecosystems by balancing food webs through controlling prey populations. Sharks also ensure there are healthy prey populations by targeting sick or injured individuals. This helps maintain the overall health of species throughout the ecosystems as it controls the spread of disease and ensures only the healthiest fish reproduce.
Sharks also affect the behavior and distribution of their prey species through fear. This indirect control on prey species can affect the greater ecosystem. By controlling prey populations, sharks ensure habitats are not overgrazed, for example such as turtles eating seagrass meadows. When sharks are present, turtles move around more and graze over a larger area of seagrass rather than overgrazing a single area. Without sharks, turtles will graze heavily in a few locations and quickly destroy the highest quality seagrass meadows, which are important habitats for many fish, shellfish, and birds.
Coral reefs can also benefit from shark defense, as the recent study indicates. The loss of sharks from coral reef habitats has seen a rise in the number of smaller species that feed on herbivorous fish. As a result, herbivorous numbers are dwindling, and without enough herbivores feeding on algae, algae will easily overgrow the coral reef. This change from the coral-dominated reef to an algae-dominated reef reduces biodiversity. A reduction in biodiversity results decreases the resilience of the reef to disturbances such as coral bleaching and storms.
Sharks Keep Carbon Out Of The Atmosphere
Since sharks help safe seagrass meadows by avoiding overgrazing, sharks have a significant role to play in the carbon cycle. Seagrasses absorb significant quantities of harmful atmospheric carbon and contain it in the plants themselves and bury it within the sediment, preventing greenhouse gasses from warming the atmosphere.
Sharks also contain a lot of carbon in their own bodies, and research has found that by depleting stocks of massive aquatic species, such as whales and sharks, we have reduced the ocean’s carbon storing potential by millions of tons. And that means more pollution in the atmosphere, which accelerates global warming.
Sharks Boost The Economy
In 2011, global shipments of shark fins were declared to have totaled more than $438 million and global exports of shark meat totaled more than $432 million. Together, this amounts to $870 million, and this does not include trade in other shark products, such as liver oil, teeth, and jaws, which are rarely documented so information is not known. These profits are unsustainable and won’t last, especially as many shark fisheries are driving sharks to the brink of extinction.
Sadly, sharks are worth a lot more dead than alive in some places because of the increasing success of shark ecotourism. In Palau, a single dead reef shark can sell for around $108, however, the same live reef shark could add about $2 million to the tourism industry in its lifetime. Killing a shark for its fins or meat provides only a one-time income, while a live shark will consistently support the local economy over its lifetime. Although the shark finning industry has been decreasing over the last 10 years, by comparison, shark ecotourism produced more than $314 million in 2013, and is likely to double to $780 million within the next 20 years.
Sharks Under Threat
Apex predators are being removed from marine ecosystems at an unsustainable rate. Unfortunately, many species of sharks are currently in danger due to shark finning and overfishing, including the scalloped hammerhead and the smooth hammerhead. What makes this particularly troubling is that sharks take many years to reach sexual maturity, so these low reproduction rates make repopulation difficult.
It’s estimated that 100 million sharks are killed by humans every year. That’s almost 200 sharks per minute. Some fisheries intentionally target sharks, while fisheries that target other species kill millions of sharks as unwanted bycatch. The cruel and wasteful practice of shark finning alone kills up to 73 million sharks every year, only to use less than five percent of the sharks’ bodies. On top of that, government-sponsored shark culls indiscriminately slay sharks and other wildlife in a misguided attempt to protect beachgoers.
What Can You Do?
Sharks have been on Earth for approximately 450 million years, long before the dinosaurs and well before trees! Sharks have survived four mass extinction events. Today, humans are pushing sharks to the brink of extinction due to unsustainable harvesting. However, removing sharks from the oceans is threatening the overall diversity and stability of food webs throughout the ocean.
Advocate For Action To Protect Sharks
Join a campaign to improve your local regulations or laws that aim to prevent and control the import and export of shark fins, as well as the sale of shark fins. Petitions are a great way of advocating for action. You can also campaign local governments to better protect key areas known to be important for sharks.
Educate Others On The Importance Of Sharks
Education is a key part of conservation. Educating others helps raise awareness of the importance of sharks and the threats they currently face. It also helps make consumers more aware about what they are purchasing, as shark meat is often mislabeled under different names (e.g., Rock Salmon, Dogfish and Flake), including endangered or prohibited species.
Eat Sustainable Seafood
If you choose to eat seafood, making sure it’s harvested sustainably makes a huge difference in reducing the amount of sharks caught as bycatch.
Donate To Shark Conservation Charities
Charities including Project Hiu, Shark Guardian and Bite-Back Shark and Marine Conservation are all fighting to end the practice of shark finning. For example, Project Hiu provides an alternative source of income for local shark fishermen through ecotourism whilst also funding local schools and providing clean water for the wider community.