A Sad Shark's Tale: The Great White

By Ruth Hendry - 09 Mar 2011 16:9:1 GMT
A Sad Shark's Tale: The Great White

Great white sharks have an unwarranted reputation. In the media, sharks are cast as villains - man-eaters and killing machines. This couldn't be further from the truth.

Great white sharks rarely attack humans and they play a vital role in the marine ecosystem. As top predators, sharks help to control many fish and marine mammal populations. Oceana released a report in 2008 entitled "Predators as Prey: Why Healthy Oceans Need Sharks".

In the report, Oceana state that the loss of sharks has led to the decline in coral reefs and seagrass beds, and the loss of commercial fisheries.

By taking sharks out of the coral reef ecosystem, other predatory fish increase in abundance and feed on the herbivores.

With fewer herbivores, macro-algae expands and coral can no longer compete, shifting the ecosystem to one of algae dominance and affecting the survival of the reef system.

In a study published today, scientists describe the research they carried out on the great white shark population off the coast of central California.

Researchers took photographs of the sharks' dorsal fins and used this to identify individual sharks. They were able to do this as the dorsal fin of great white sharks is unique to each individual, just like a human fingerprint.

Much to the scientists' dismay, they found far fewer great white sharks in this area than they expected. Only 219 mature and juveniles were found, which is substantially smaller than populations of other large marine predators. As this region is thought to support one of the world's largest populations of great white sharks, this finding does not bode well populations elsewhere

Great white sharks are, along with other large marine predators, declining globally due to fishing, habitat loss and pollution. Continuing assessment and monitoring of remaining shark populations is crucial to ensure these amazing species do not decline any further.