Tuesday October 9, 2012
Asian Shark Conservation gets more data on sharks
By NATALIE HENG
One group of divers decides to do something about the dearth of data on sharks.
GUY RAYMENT, 47, had overheard lamentations about shark data deficiency many times before. One day, just as divers do, he was complaining about the severe decline in shark populations around the world when his friend said: “Why don’t you stop complaining and do something about it?” He thought she had a good point, and that was how the Asian Shark Conservation group was born.
Worldwide, there is a vacuum of information on shark populations, behaviour and ecology. Around 2% of the world’s 500 or so shark species are at “extremely high” risk of extinction in the wild, 4% are at “very high” risk, 11% are at “high” risk, and 13% are close to qualifying or likely to qualify for a threatened category, in the near future.
Just 23% of our shark species are safely listed as of “least concern” in the International Union for the Conservation of Nature’s (IUCN) Red List of endangered species. That leaves roughly half of the world’s shark species literally swimming in a black hole of information.
The best way Rayment and his group of diver friends decided they could address that would be to build a shark sighting database. Not enough is known about the 47% of “data deficient” shark species to assign them a definitive category of threat under the Red List. Already a notoriously difficult animal to study, as sharks deplete further, gathering data on them will only become harder.
But divers can help. They are uniquely privileged, and from behind their underwater masks of tempered glass, it’s not just the majesty of the ocean they get to witness, but its decline. Most divers record their sightings into logbooks, and these jottings can be incredibly useful.
Sabah-based Tropical Research and Conservation Centre (TRACC) director Steve Oakley has studied sharks for over 30 years, 16 of which have been spent in Malaysia. A while ago, he began amassing logbook data through e-mail submissions to reconstruct how shark sightings have fluctuated over the years. Preliminary data from his 2011 Global Shark Survey shows that of the 109 shark species recorded in the South China Sea, only 18 have been seen in recent memory. This, Oakley says, means that 91 species might now be regionally extinct.
He is supportive of Asian Shark Conservation’s efforts. “Where my surveys present a historical picture of decline, what they are doing will help us keep track of how frequently sharks are being sighted now, and into the future,” he notes.
The group’s web-based shark sighting database will fill a niche in South-East Asia, and provide data to complement TRACC’s surveys. The website (asiansharkconservation.com) is up and running, ready for divers to register and log in their data.
Making the case for conservation effort requires good, science-based information – which is why amassing the data is important. Oakley says diver-assisted shark surveys have helped in the past. Information from Britain’s Shark Trust helped extend protection for tope, a hound shark that has been targeted heavily for its meat, fins and liver oil.
Most shark species take many years to reach sexual maturity. They have long gestation periods and only breed every second or third year, usually giving birth to few offspring. So sharks don’t respond quickly to the removal of many individuals from a population.
Worldwide, the vulnerability of sharks to over-fishing is starkly contrasted with demand. Sharks are eaten all over the world: spiny dogfish as fish and chips in Britain or schillerlocken in Germany; porbeagle is prized as “veal of the sea” in France; while mako, thresher or blacktip shark make popular steaks in the United States. Also, shark liver oil is used in all kinds of industries while shark skin is used to make leather. And let’s not forget the Asian tradition of shark fin soup.
Huge declines present us with a resounding wake-up call: spiny dogfish and porbeagle populations have dropped 80% in the eastern Atlantic, and hammerheads by 89% in the north-west and western central Atlantic. Meanwhile, 14 of the species most prevalent in the shark fin trade have seen declines between 50% and 100% (total population collapse) depending on geographical regions. So far, one third of pelagic (open ocean) sharks and rays are threatened with extinction.
Official figures tend to underestimate the problem. The main reference used by the Food and Agriculture Organisation is catch data, which comes from commercial fishing fleets.
In 2006, a reported 750,000 tonnes of sharks, rays, and chimaeras were landed.
However, a study which used fin trade records to estimate the weight of sharks killed annually came up with a figure of between 1.21 and 2.29 million tonnes, the equivalent to between 26 and 73 million sharks.
Actual mortalities are probably much higher because this data excludes figures for sharks killed for domestic fin markets, sharks killed only for their meat, illegal catch data, bycatch and shark landings from artisanal fisheries.
“Sometimes, figures for catch can be misleading,” says Oakley.
“Let’s say hypothetically, five years ago, you catch 100 fish. And today, your catch is still 100 fish.
“It looks like nothing has changed, but the fisheries industry may have had to double their fishing efforts to achieve that same figure,” Oakley explains.
It took Oakley 10,000 hours worth of meticulous data collection to make a solid case, but his data is partly responsible for Sabah’s decision to push for a total ban on shark hunting in the state.
His data shows a 98% decline in whitetip reef shark population in Sabah.
He says things are worse in Peninsular Malaysia, where whitetips have been wiped out.
In contrast, his data shows about 300 to 350 whitetips in the reefs of Sipadan marine park, where fishing is banned.
On the other hand, no whitetips swim around the similarly sized, but unprotected, reefs of Pom Pom Island. Both islands lie off the eastern coast of Sabah.
Having such information helps make the case to pressure governments into action, be it gazetting more marine protected areas, enforcing tougher legislation on finning or listing more species as protected.
Rayment, a dive instructor, says with the new Asian Shark Conservation database, divers can help contribute to our understanding of questions like “Which sharks are being hit the hardest?” and “How fast are they declining?”
To support the cause, divers need to register on the Asian Shark Conservation website, and key in their observations, such as what species was seen, where, and when.
There are also additional boxes to state if the shark had been tagged, and if you are a pro, the sex of the fish.
There’s also a box for non-sightings, and photographs can be uploaded to help with verification.
“Now, we just need as many divers as possible to go diving, so we can collect as much data as possible,” says Rayment.
Guarding shark numbers