Imperilled: Shark populations in free fall throughout the world
December 6th, 2011 - 11:20am
Rob Williams and his colleagues weren't even looking for sharks
Vancouver Sun, 23 October 2010 By Larry Pynn
The University of B.C. researcher was aboard a 20-metre research sailboat off the B.C. coast for three summers, surveying for marine mammals such as whales, dolphins and porpoises.
But it was the appearance of shark fins -- one, then another, and another -- slicing through the cold blue water that surprised the research team. Most were salmon sharks, but there were also some blue sharks ranging in length to almost four metres.
"This was not subtle," Williams said. "This didn't take a lot of sleuthing to discover."
The team had tripped upon a shark "hot spot" in Queen Charlotte Sound and southern Hecate Strait, one of the Pacific's most storm-tossed stretches.
Later, when researchers crunched the numbers and interpolated for areas they had not navigated, they estimated 10,000 ocean-going, or pelagic, sharks -- a veritable curtain of serrated teeth -- were drawn in summer to this area of the B.C. coast.
Who knew they were there?
Who can say what's attracting them? Although a good guess is salmon migrating south in summer.
And who knows whether the numbers are growing or represent only a fraction of what once existed?
"We are reminded of how many black boxes, how many unknowns are still out there," said Williams, whose findings are newly published in Marine Ecology Progress Series.
STRANGERS IN OUR MIDST
Sharks have been around for 400 million years, yet remain strangers to us.
What little we do know is that they are especially vulnerable to overharvesting because they are late to mature, produce few offspring and are relatively slow growing.
As the ocean's top predators, sharks fill an important ecological role -- much like terrestrial predators such as wolves -- and are part of the greater web of marine biodiversity that Canada has committed to protect.
The Oceans Act affirms that "conservation, based on an ecosystem approach, is of fundamental importance to maintaining biological diversity and productivity" in Canada's Pacific, Atlantic and Arctic waters.
The Species At Risk Act provides for the conservation and recovery of individual species, and has already been applied to sharks such as the endangered basking shark in B.C.
Yet in Canada, and around the world, shark populations are in free fall.
A new research paper reveals there are 28 species of sharks in Canada's oceans -- more than half of them found off the B.C. coast -- ranging from the common dogfish to exotics such as great whites and hammerheads. Of those 28 species, 12 are rated as vulnerable on the International Union for Conservation of Nature (IUCN) red list and another seven as near-threatened.
The major driving factor is Asian demand for pricey shark-fin soup -- strictly a status symbol, the fins providing no flavour. Between 26 million and 73 million sharks are estimated to be traded annually for their fins, an unsustainable harvest by any measure.
Many die horrible deaths, their fins hacked off and their bodies dumped back into the water alive, unable to swim, feed or defend themselves.
Other factors in sharks' decline include insufficient monitoring and lack of international political will, allowing the slaughter to continue.
The situation is exacerbated by the fact that sharks -- similar to the endangered bluefin tuna -- can migrate vast distances spanning the coastal waters of multiple nations.
Lack of research also makes it harder to justify shark conservation, argues Nick Dulvy, Canada research chair in marine biodiversity and conservation at Simon Fraser University and co-chair of IUCN's shark specialist group.
"There are probably about 150 global experts in shark, skate, and ray ecology and conservation and probably 300 species threatened or near threatened. We've got to save two species each. If you're a primate ecologist studying monkeys, there's probably 20 monkey scientists for every monkey species."
Blame the 1975 Hollywood blockbuster Jaws for giving the species a bad name, but there just hasn't been the same groundswell of support for sharks as there has been for other endangered animals.
IUCN reported in 2007 that 32 per cent of the world's pelagic sharks and rays are threatened. Of those, six per cent are endangered and 26 per cent vulnerable. Another 24 per cent are near-threatened.
Dulvy warns that 10 of the 20 shark species that "live out in the high seas" are vulnerable -- including the great white and mako sharks -- and another five are near-threatened.
CANADA'S ROLE IN DECLINE
Canada is both complicit in the decline of sharks around the world and the subject of criticism for not doing enough to protect sharks that inhabit its own waters.
According to the Canadian Food Inspection Agency (CFIA), Canada imported 311,600 kilograms of shark products in 2009, of which 77,000 kilograms were dried or frozen shark fins.
Those statistics don't tell us what species of sharks are being imported or the total number of sharks.
But DNA tests organized by The Vancouver Sun provide some insight into the trade.
Ontario's University of Guelph conducted the tests on shark-fin samples from two sources: purchases by The Sun in suburban Richmond, the new centre of Chinese culture in B.C.; and samples provided by the World Wildlife Fund office in Vancouver, where the father of one staffer works at a Chinese restaurant.
The test results confirm that sharks globally at risk are among those marketed locally, including four species listed as “near threatened” — blue, silky, blacktip, and spinner — on the IUCN red list.
Another four species — bigeye thresher, shortfin mako, longfin mako, and dusky — are listed as “vulnerable,” a more serious ranking, on the red list.
Two one-pound (0.45 kilogram) packages of dried shark fins from Richmond contained 10 and 27 fins, mostly smaller and poor-quality product.
Sharks have eight fins that could potentially be hacked off, the four largest and most profitable being the dorsal (top), caudal (tail), and two pectoral (side) fins.
Based on The Sun's purchases, one can only guess at the substantial number of sharks represented by Canada's importation of 77,000-kilograms of fins.
"We're one of the richest countries in the world," said Ernie Cooper, a WWF specialist in international wildlife trade. "We provide a significant market for shark fin. If there was no market for shark fin, then there'd be no targeted fishing of sharks."
Yet, the only federal laws broken relate to mislabelling, not sales of species at risk.
CFIA provides a list of acceptable retail names for shark products based on 11 officially recognized species. But DNA tests on the eight shark samples provided by The Sun found six shark species for sale that are not on the list, meaning their sale is not permitted in Canada.
Not that anyone -- seller, consumer or government inspector -- could identify a shark fin by species simply by looking at it.
A scientific paper in the draft stage, based on The Sun's purchases, concludes: "Currently, regulation of wildlife sale within these cultural markets is impeded simply because of the inability to accurately identify specimens.
"Generally, custom officials are not trained to be familiar with scientific nomenclature, however not even trained taxonomists are able to morphologically identify dried fragmentary remains of specimens. Therefore, it is unknown how many protected or endangered species enter Canadian borders each year without detection."
CANADA'S MURKY WATERS
Boris Worm, an associate professor of biology at Dalhousie University in Halifax, and master's student Aurelie Godin have just finished the first comprehensive assessment of Canada's 28 shark species, published online in Marine Policy.
"Very few people are aware we have 28 species of sharks here," Worm said in an interview. "A lot of people just don't know we have sharks in our waters."
The federal Committee on the Status of Endangered Wildlife in Canada (COSEWIC) rates three as endangered -- the porbeagle and great white shark in the Atlantic and the basking shark in the Pacific.
Sightings of the basking shark are so rare off the B.C. coast that the federal government conducts regular coastal overflights for them -- so far without spotting a single one.
COSEWIC also lists the shortfin mako as threatened in the Atlantic, and three as species of special concern -- sixgill and soupfin (tope) sharks in the Pacific, and basking sharks and blue sharks in the Atlantic.
Worm's report notes that Canada continues to allow a fishery on porbeagle, with a catch quota of 185 tonnes.
Up to 100 tonnes annually of shortfin makos can be landed in the Atlantic, even though they are listed as threatened.
The report found "major shortcomings" with Canada's shark management, noting the Species at Risk Act has "not yet yielded any meaningful protection measures for sharks." It also finds "the state of knowledge" for non-commercial species is low, with poor regulations related to shark bycatch.
"Shark conservation is challenging, as many species are highly migratory and several countries share the management of single stocks," the report found.
Worm said commercial longline boats on Canada's East Coast lack the on-board observers or video monitoring mandatory on the Pacific coast, meaning there is little information on the number and species of shark bycatch.
"We are largely in the dark," Worm said. "Only one to five per cent of boats are monitored. It's unfortunate."
Efforts to reduce shark bycatch would benefit fishermen by reducing damage to their gear and the time required to release sharks. Worm noted that a screen could easily be adapted to mackerel traps to keep out basking sharks, just as shrimp trawls in the Gulf of Mexico have been fitted with escape hatches for turtles.
In addition, seasonal closures could be implemented where sharks are known to congregate.
In Greenland, so many sharks are caught in the shrimp trawl fishery there is interest in using their carcasses for biofuel.
"To me, that shows disregard," Worm said.
Worm and Godin make several recommendations: catch and release of all sharks that have a conservation concern; monitoring of all fisheries with high bycatch of sharks and of independent shark surveys to find out more about populations; investigation of fishing methods that reduce the chance of catching sharks; development of handling policies that better ensure survival of sharks released; ensure that all sharks brought ashore still have their fins attached; implement a catch-and-release sport fishing policy "for all sharks, without exception."
The two researchers also recommend that recreational shark derbies be banned and replaced with tag-and-release programs that promote shark conservation. Their report said shark derbies in Nova Scotia kill 10 to 20 tonnes of blue shark annually, noting "the message conveyed to the public" by such events is concerning. (Sharks smaller than 240 centimetres must be released, along with porbeagle sharks.)
Their study also noted that a scientific paper in 2006 estimated 26 million to 73 million sharks annually are traded for their fins, "a number that exceeds the reported catch by three to four times."
Responding for Ottawa on the East Coast, Steve Campana, senior scientist at the Canada Shark Research Laboratory, said he shares Worm's and Godin's concerns for shark populations around the world.
"Compared to other countries, Canada is one of the best. But have we reached the level have more steps to take. Canada is one of those."
Campana argued that commercial fishing of the porbeagle -- rated endangered by COSEWIC -- is low and closely monitored. He estimated the population at 200,000 to 250,000, extending well beyond Canada's 200-nautical mile economic zone and into the northeast U.S., and growing despite the modest fishery.
The mating ground of porbeagle sharks off southern Newfoundland has been closed to fishing.
"Many sharks are in far worse shape [than the porbeagle]," he said. "The great white shark, for instance: There is a very real possibility that species will go extinct in our lifetime. That is a disturbing thought."
In an interview from Dartmouth, N.S., Campana said it's important to note that sport fishermen are not permitted to keep sharks except at fishing derbies, and that the blue sharks being caught are plentiful.
Getting to see a shark -- even a dead one at a fishing derby -- can also have some benefit in terms of public education, he said, adding that scientists are present to examine every shark caught and put tags on them.
Fisheries and Oceans Minister Gail Shea refused to be interviewed by The Sun on shark management.
B.C. HOME TO 15 SPECIES
Researchers are still just getting to know the sharks in Canada's Pacific waters.
In early August, federal marine researcher Jackie King spent eight days up to 90 kilometres west of Barkley Sound aboard the Canadian Coast Guard research vessel Neocaligus as part of an international shark-tagging project. She endured sea sickness and sleeplessness as the 18-metre vessel roiled against the Pacific rollers.
Just one set of 75 barbless hooks baited with herring caught a whopping 52 blue sharks, evidence that where the species schools, it can be found in large numbers.
Four blue sharks and two soupfin sharks were fitted with satellite transmitters to provide information on their wanderings.
As of mid-October, two of the blue sharks had been tracked to California: one about 110 kilometres off Mendocino, the other more than 200 kilometres off Santa Cruz.
A new report by King, along with emeritus scientist Sandy McFarlane and marine biologist Romney McPhie, all of them with the federal Pacific Biological Station in Nanaimo, documents 15 species of shark in B.C. waters.
"That would be surprising to people," King said. "It's because we don't have fisheries for them. We don't come across them, so they're overlooked."
Sharks cited in the study include great whites that washed ashore, mainly on the east side of Haida Gwaii, and a smooth hammerhead caught off the west coast of Vancouver Island in the 1950s.
The population of great white sharks could increase in future years as they come north to feed on B.C.'s healthy population of harbour seals, thought to have increased 10-fold to an estimated 105,000 since the federal government afforded the marine mammal protection from commercial harvest and bounties in 1970.
Commercial halibut fisherman Gary Robinson was fishing about 25 kilometres offshore in Dixon Entrance in waters about 200 metres deep in 2008. Hauling in his line, he was surprised to see he'd made two catches on one hook -- an arrowtooth flounder, and a Pacific sleeper shark that sought to eat the flatfish.
"In the 1980s, we used to get a couple per week while halibut-fishing," he said. "The last 10 or 15 years we have been getting a couple per day ... sometimes more if fishing deep."
He said the sharks have no market value and are discarded.
"Generally when we catch one of these I just resume hauling and the hook pops out once the weight of the fish comes out of the water," he said. "They seem to have very soft jaws. The odd time the gangion [the thinner branch line] will break if it has been frayed by the fish's fighting. Then it does have to live with the hook, probably for life."
Exactly how many sharks caught as bycatch ultimately die from their injuries is unknown.
In the three-year period ending with 2009, the hook-and-line groundfish fleet reported catching a total of 4,622 sharks, not including the spiny dogfish, which is the subject of a commercial fishery.
Three species accounted for almost four-fifths of the total -- 1,341 sixgill sharks, 1,227 Pacific sleeper sharks and 1,068 blue sharks, the others listed as mackerel, salmon, soupfin, requiem, brown cat, and even one endangered basking shark.
A total of 802 sharks could not be identified by fishermen, close to 20 per cent of the total.
Tameezan Mawani, regional groundfish manager for federal fisheries, said the commercial fleet can expect soon to be required to monitor more closely its bycatch of sharks and other marine mammals, as well as seabirds.
Ottawa is considering producing laminated cards to help crews more accurately identify the various species.
While commercial fishermen are required to remove sharks "in the least harmful way possible," there will be a "code of conduct" produced soon to improve catch-and-release methods.
Although there appears to be little appetite in B.C. for targeted shark sport fishing, the individual recreational harvest, excluding sixgills, is 20 per day, a limit that is soon to be changed by federal fisheries.
Mawani said there will be consultations with the Sport Fishing Advisory Board this fall. Based on regulations in U.S. states on the west coast, she expects sport fishing of sharks to be largely catch and release, except for a daily
retention limit of perhaps one or two for dogfish and maybe salmon shark.
PUBLIC OPINION SWAYS
While Jaws generated unreasonable public fears of sharks, there has been a tidal shift in more recent years.
Canadian filmmaker Rob Stewart's award-winning documentary Sharkwater, released in 2007, went a long way toward sounding the alarm about the global decline of sharks and the negative impact their removal could have on marine ecosystems. Chinese celebrities are stepping up to the conservation plate, just as their Caucasian counterparts have done over the years for the more charismatic tiger, panda and harp seal. Basketball star Yao Ming, Olympic diving champion Guo Jing, Hong Kong actor Tony Leung and others have joined campaigns to discourage consumption of shark-fin soup.
In Hong Kong and beyond, guests to Chinese wedding banquets are encouraged to reduce their cash gifts to 70 per cent if shark fin soup is served and to donate the 30 per cent to conservation non-profit organization and charities.
Closer to home, a new Vancouver organization, Shark Truth, sponsored a contest that dangled a trip to Mexico for Asian couples vowing not to serve shark-fin soup at their weddings.
Protecting sharks has become cool. And none too soon.
Sharks fill an important niche as top predators, and their removal could have unforeseen risks for the greater marine ecosystem.
"We know that sharks all around the world are declining," the World Wildlife Fund's Cooper said. "We also know that sharks play a critical role in the health of other fish species."
The Census of Marine Life -- a 10-year international effort to catalogue the planet's marine species, concluded earlier this month -- noted that the effects of global overfishing are more obvious on individual species than on larger marine ecosystems.
In one study associated with the census, researchers found that overfishing of top-of-the-food-chain predatory sharks in the northwest Atlantic has increased the number of mesopredators -- medium-sized predators such as rays, skates and smaller sharks upon which the larger sharks feed.
Increased numbers of cownose rays are thought to have impacted the bay scallop so seriously that in 2004, North Carolina closed the previously healthy fishery.
In Japan, excessive fishing of the larger sharks caused a population boom of long-headed eagle rays, which led to decimation of both wild and farmed shellfish, the census reports.
To Dennis Thoney, director of animal operations for the Vancouver Aquarium, these sorts of studies into overfishing of sharks hint at a beneficial ecological impact provided by sharks whose extent remains unknown.
"We're only starting to see it, and it's very indirect," said Thoney, staring down at an aquarium tank filled with tropical blacktip reef sharks. "They're very important predators, extremely important in regulating other fish populations.
"The biggest benefit? We haven't seen it yet."