Say What? Sharks in the water indicate a healthy ecosystem!
A white-tip reef shark is a sign of a healthy reef photo by Phanor Montoya-Maya
In the past few weeks, Nature Seychelles staff working on Cousin Island Special Reserve and in the Reef Rescuers project have sent in interesting reports and photographs of activities going on in the sea. From sightings of sharks devouring a sperm whale, to sting ray pile ups and just the general beauty of the underwater world.
There was a flurry of comments and questions on Nature Seychelles’ social media page when photos of a large shiver of sharks circling a clearly injured sperm whale were posted in late December 2014. Boatmen alerted Cousin Island Special Reserve staff of the incident just off Praslin. They headed straight there to witness and capture the event.
Sharks feeding on a sperm whale near Praslin photo by Chris Delpont
At least three dozen tiger sharks and over a dozen bull sharks were making a meal of a sperm whale. There were comments ranging from sympathy for the whale, what a scary event to witness, how spectacular it must have been to see this, but mostly on the affirmation of the cycle of life and the marvel of the natural world.
“This is indeed a natural event,” said Dr Phanor Montoya-Maya, the Technical and Scientific officer of Nature Seychelles’ Reef Rescuers project. “Dead or agonizing whales are a great feast for sharks, especially tiger and bull sharks, proof that nothing in nature goes to waste. But, good, authenticated records of natural, unprovoked feeding behavior like this one are scarce. Thus opportunities like this offer a great platform to understand shark behavior and to educate the public about sharks,” he explained.
Sting rays photo by Phanor Montoya-Maya
There are about 450 species of sharks in the world, which range in size from small dwarf lantern shark which is a deep sea shark, only 6.7 inches long to the whale shark which grows to 39 feet long, the largest fish in the world. Sharks are commonly found in depths of 6,600 feet in all seas with the exception of the bull shark and the river shark which can survive in both fresh and sea water.
Despite the common fear of shark attacks in Seychelles, especially after the two unprovoked attacks at Anse Lazio, Praslin some time ago, humans are in fact more a threat to sharks than vice versa, due to commercial overfishing. 100 million sharks are fished from the world’s oceans annually. But studies in some countries have shown that sharks are one thousand times more financially valuable alive in the water than dead on a plate because they can form the core of long term eco-tourism programs. The majority of sharks are actually shy and do not attack humans unless provoked hence the rise of shark diving tourism in numerous places around the world.
One such example is the island state of Palau where shark fishing was banned. Palau is reportedly earning more from shark tourism than it did from shark fishing. What’s more, in less than a decade, the protection of sharks has not only been beneficial to these kings of the sea but the entire underwater kingdom as well. The numbers of other marine species are reported to have increased suggesting that the presence of sharks indicates a healthy underwater ecosystem.
The underwater beauty of Cousin Island Special Reserve photo by Phanor Monytoya-Maya
Phanor has noticed white-tip reef sharks (Triaenodon obesus) frequenting the Reef Rescuers’ coral transplantation site within the Cousin Island Special Reserve. He noted that this was encouraging to Nature Seychelles’ Reef Rescue project work. The Reef Rescuers Project was initiated in 2010 and aims to avert the devastating effects of climate change on coral reefs, specifically, ocean warming and coral bleaching.
“The presence of predators like sharks in a reef can be considered an indication of a healthy ecosystem,” says Phanor. “We’ll keep monitoring the transplantation site to assess the positive effects that our active reef restoration project had on rehabilitating damaged coral reefs around the inner granitic islands of the Seychelles.”
