Sable Island’s cod killer?
The new plan to slaughter seals blames seals for the cod fishery collapse, but a large seal population might just be the cod’s best hope.
Reprinted from The Coast
July 1, 2010
by Linda Pannozzo and Bruce Wark
One morning in early April 2003, the villagers of Smith Sound, Newfoundland, awoke to a glimpse of what it might have been like to live there 500 years earlier. The sound was brimming with cod, as far as the eye could see. Villagers rushed out in their boats, scooping the fish up in nets and buckets. In three days, they hauled hundreds of thousands of cod aboard their boats, in the end totaling 780 metric tonnes---roughly the combined weight of 500 average-sized cars.
It was a reminder of the days when the fish were so abundant off the shores of Newfoundland they could be caught in baskets lowered over the sides of boats, except for one glaring difference: these fish were dead.
Many villagers quickly blamed seals for chasing the fish into water that was so cold they froze to death. For a time, even some government scientists entertained this possibility. But a federal investigation showed the seals weren't to blame; the subsurface water in the entire sound was colder than it had been at any time during the previous decade, and the cod froze to death.
While media reports of the cod die-off described people scrambling to fill crates and barrels destined for the nearby fish plant, the story was also about how seals had once again become the usual suspects---"vermin fish-eaters"---easily blamed for anything that went wrong in the fishery. And things had gone horribly wrong.
On July 2, 1992, then-federal fisheries minister John Crosbie announced that Atlantic groundfish stocks had collapsed, causing despair in countless fishing communities across Atlantic Canada and throwing 40,000 people out of work. The once-abundant Atlantic cod had crashed to the point of no return. The arrival of modern trawler fleets in the 1950s---equipped with fish-finders and sophisticated gear---marked the beginning of the end. Whole schools of cod could now be found, caught, processed and frozen 24/7. These factory-freezer trawlers were so effective that 200 of them were able to catch eight million tonnes of northern cod between 1960 and 1975. By comparison, it took a century to catch that many fish after John Cabot's arrival in 1497.
In 1990 Leslie Harris, president of Memorial University, chaired an independent review of the state of the northern cod stocks. He described the offshore factory trawler as "the most destructive fishing machine yet devised by human ingenuity." Members of the traditional, small-scale, inshore fishery, who operated from small boats closer to shore, had warned since the mid-1980s that the cod were disappearing, but the government had failed to respond. Today there's little disagreement that overfishing by the big offshore trawlers combined with government mismanagement caused the cod collapse, which turned one of the most fertile fishing grounds in the world into a wasteland.
Fast-forward two decades and the cod still show no signs of recovery. Estimates vary depending on the stock, but scientists say that only a tiny fraction of the original cod biomass is left in Atlantic Canada, and some stocks are close to extinction. In 2003, the Committee on the Status of Endangered Wildlife in Canada designated the Maritime cod population a species of "special concern" while it declared the worse-off Newfoundland and Labrador population "endangered."
Small-scale inshore fishers, pushed to the brink of financial collapse, blame the seals for the fish not coming back. They argue that an expanded grey seal cull is needed to save the cod. But many scientists and conservationists believe the truth is more complex and that seals are being blamed for the federal government's mismanagement of the cod stocks---deflecting attention from the continued use of destructive fishing methods.
Grey seals are, indeed, a tempting target, especially the huge numbers that gather on Sable Island every winter to breed and give birth. Killed historically for their oil and skin, their population had been severely depleted by the 1970s, when only a few thousand were whelping on the island. But since there has been no large-scale hunting of grey seals in recent years, the Sable Island population has grown to around 300,000. The island is now the world's largest grey seal colony---a place where it would be easy to kill large numbers of the animals in just a few days.
Last year, under growing pressure from the fishing industry, the federal Department of Fisheries and Oceans commissioned a study to examine the costs and logistics of "managing" the Sable Island grey seal population. (See "How to kill 220,000 seals on Sable Island: the DFO plan," May 27, 2010). DFO hired CBCL Ltd., a Halifax-based engineering firm, to consider two options: first, to figure out what it would take to slaughter 220,000 seals over a five-year period, and second, to consider how to conduct a contraceptive vaccine program targeting 16,000 females each year for five years.
According to the study, which The Coast obtained through an Access to Information request, either of the two options would have to take place between December and early February, when the beaches and dunes are covered with nursing mothers and their babies.
The study describes the logistics of killing and moving tens of thousands of seal carcasses over a 25-day period. In the first year, 10 seals would have to be killed every minute to achieve that year's target of 100,000. Modified tree-hauling equipment would be needed to move the carcasses either to mobile incinerators or to places where they would be stacked in containers, slung from the island by helicopter to a supply vessel and then transported to a "shore base" for disposal.
Such a massive operation in Sable's protected and remote wilderness would cost $35 million, while an immunization program would run to somewhere between $12- and $23 million.
"To any reasonable person, this is a holocaust situation and I don't use that word lightly," says Bridget Curran, director of the Atlantic Canadian Anti-Sealing Coalition. "There's no science to support claims that seals are responsible for ground stock depletion or are responsible for the failure of groundfish stocks to rebound," she says. "It's a ridiculous scheme, it's unnecessary, it's inhumane [and] has no basis in science."
Seals and science
Bridget Curran is not a scientist herself, but Sara Iverson is. She's a researcher in physiological ecology at Dalhousie University. Iverson has studied the diets of grey seals on Sable Island for 17 years using a technique she developed to analyze the fatty acids in their blubber. "Fatty acid signature analysis is based roughly on the principle 'you are what you eat,'" she says. Iverson analyzes a small piece of blubber, taken from a live seal, to calculate both the mixture and amount of prey the seal has eaten over several months. She found that cod are not a staple food for grey seals.
"Cod make up a very small proportion of their diet," she says. "By far the largest diet items for grey seals on the Scotian Shelf are sand lance, redfish and other forage species such as capelin and herring." Iverson says seals prefer eating these fish because they are abundant and have a high fat content (five to 14 percent) compared to cod, which is only one percent fat.
"Grey seals are only one small cog in a very large wheel," Iverson says adding that the complex marine food web makes it impossible to point a finger at any one species. "It's well known that the absolute largest predators of fish are other fish. Cod themselves are extremely cannibalistic and are large consumers of forage fish such as sand lance, capelin and redfish." She says that when the cod stocks collapsed, the whole marine food web shifted. With few large cod left, the population of the smaller fatty fish exploded, and since they're the preferred prey of grey seals, the seal population ballooned too.
According to Iverson, there is evidence, based on DFO's aerial surveys, that the exponential growth of the grey seal population on Sable Island has stopped. "The population was still increasing several years ago, but not nearly at the rate it had been over the past few decades," she says. The results of the most recent survey won't likely be available for a few months, but Iverson predicts it will probably show further stabilization of the seal population. She concludes there's not enough scientific evidence at the moment to justify either a cull or the sterilization of grey seals.
"Scientifically we don't really have clear evidence that removal of grey seals would result in the recovery of those cod stocks," she says. And tinkering with a complex system could result in unintended consequences. "We have a hard time managing even simple ecosystems in terms of food webs. This is a very complex system and we don't have any idea would happen if we removed one cog."
Seals and the cod collapse
That's a point that strikes a chord with Jeff Hutchings, a Dalhousie University biology professor who specializes in Atlantic cod. In 1997, he co-wrote a paper with the late Ransom Myers, a well-known fisheries conservation biologist, about the cause of the cod collapse in Atlantic Canada. They concluded it resulted from a combination of overfishing, overestimation of the size of the stock, as well as increased discarding and non-reporting of undersized fish. The paper emphasized that seals "clearly did not cause the collapse of the cod."
Like Iverson, Hutchings argues that the ocean is not a simple two-species predator-prey ecosystem, and that treating it this way would have unknown consequences. "Cod and grey seals do not exist on their own in the marine ecosystem and there have been other changes in abundance of species that compete with cod and that eat cod and cod eggs."
In 2007, Boris Worm, a marine ecologist at Dalhousie, testified about the shifting marine food web during hearings at the Nova Scotia legislature. He pointed to increases in the numbers of small pelagic fish which eat the larvae and eggs of cod and concluded that because seals feed on pelagic fish "seals today are actually not hindering the recovery of cod, but actually are good for the recovery of cod."
Jeff Hutchings has a slightly different take on the question of whether seals are interfering with the recovery of the cod. It all depends, he suggests, on the size and location of the remaining stocks. Hutchings points out, for example, that according to DFO estimates, grey seals are responsible for about 10 percent of natural cod mortality in the eastern Scotian Shelf and only one percent in its western waters. The Scotian Shelf lies off the eastern coast of Nova Scotia. Hutchings says it's a somewhat different story in the southern Gulf of St. Lawrence, where cod stocks are already teetering on the edge of extinction.
"Even if you were to remove all the seals on Sable Island, it would have a negligible impact on cod on the Scotian Shelf and maybe some impact on the recovery in the Southern Gulf of St. Lawrence," Hutchings says.
But he also points to other factors affecting the cod, such as fishing practices. While the fishery for cod is currently limited, bycatch of cod may not be. Bycatch is the term used to describe those fish taken by accident in trawl nets, gill nets and longlines. Numerous studies have shown that the vast majority of fisheries bycatch is discarded, either dead or in poor condition. According to Hutchings, "bycatch of cod is another factor affecting their recovery."
During those 2007 hearings at the legislature, Liberal fisheries critic Harold (Junior) Theriault complained about the illegal dumping of cod bycatch. On Georges Bank, "there's hundreds of tonnes of codfish going over the side, dead, not being reported, because they can't report it, they can't bring it in, they can't dump it, so they can't report it even being dumped," Theriault said.
It's a point that's hotly contested by Denny Morrow, executive director of the Nova Scotia Fish Packers Association. "It is so important that we cut through a lot of misinformation that's out there and a lot of the emotional trappings that go with this issue," he says. Morrow, who strongly favours a cull of grey seals on Sable Island, says that government monitoring of the number of cod taken accidentally shows that bycatch is not the reason why the stocks are failing to recover. He insists that seals are the main culprits, especially as their numbers rise. "These are very large predators, adults can weigh 600 to 1,000 pounds," he says. "They're eating a lot of fish."
Morrow is also concerned about parasite worms that seals can pass on to cod, possibly affecting the health of the fish while making them less commercially attractive. "We've found that fish that we've gotten in that moratorium area off eastern Nova Scotia has been so infested by these parasites that even if the fishery were open, we wouldn't be able to do anything with the fish. You can't economically pick them [the worms] out."
For Morrow, the main issue is the survival of Nova Scotia fishing towns. "Our young people who would like to stay and fish increasingly have to move," he says. "I'm just a bit surprised that there is more concern about the seals on Sable Island than there is concern about the people that live in these coastal communities."
Dal biologist Jeff Hutchings agrees that a cod recovery plan is needed to preserve the fishing communities Morrow refers to, but Hutchings adds the federal government has shown no real commitment to developing such a plan. He says it's remarkable that nearly two decades after the collapse of the cod, fundamental change in the fishery has not taken place. DFO still has no recovery targets, no timelines, no harvest control rules. According to Hutchings, going ahead with any form of seal cull or contraception plan in the absence of a comprehensive recovery strategy would simply be "irresponsible."
In the foggy Atlantic, 300 kilometres southeast of Halifax, lies the narrow, crescent-shaped sand bar called Sable Island, long known as the "graveyard of the Atlantic" because of the many ships wrecked there. Sable is a wild place with shape-shifting sand dunes held together by the long roots of the marram grass that feeds the island's famous wild horses. Last month, federal and provincial politicians announced that Sable will be designated a national park, a decision welcomed by environmentalists because it will raise the level of protection for the island's fragile natural beauty and biodiversity. But this protection does not apply to seals.
At a public meeting held last week in Halifax to discuss the future of Sable Island, Doug Harvey, a planner with Parks Canada said that any decision to cull seals there would have to be preceded by public consultations. In the meantime, Parks Canada is asking for public input on the future of Sable Island as a national park via its website, email or letter before August 15.
Although environmentalists welcome giving the island national park status, they also worry about the continued destruction of ocean life. A raft of scientific studies worldwide show we are creating less diverse and less stable marine ecosystems. Oceans everywhere are being emptied, not only of fish species due to overfishing but of plankton---the foundation of the entire food web. All this means that overfished populations, like the cod, are not only more vulnerable to environmental change, but much less able to bounce back.
"Industrial fishing has scoured the global ocean. There is no blue frontier left," said Dalhousie marine ecologist Boris Worm in a 2003 study that appeared in the scientific journal Nature. The study found that since 1950, 90 percent of all large fish, including sharks, bluefin tuna and Atlantic cod, have disappeared from the world's oceans. Worm and his co-author, the late Ransom Myers, wrote that the depletion of these large predators could "bring about a complete re-organization of ocean ecosystems, with unknown global consequences."
It's a concern shared by Rebecca Aldworth, director of the Canadian branch of Humane Society International. She points out that seals are also top ocean predators and that they co-existed for centuries with wildly abundant cod. Top predators, she says, are vital to the health and abundance of the species they prey on in complex ocean ecosystems.
"We shouldn't be talking about how to control or reduce seal populations," Aldworth says, "we should be protecting seals, not removing them from the ocean ecosystem, because we need them to help fish stocks to rebound."
The Smith Sound cod die-off in April 2003 may provide us with a cautionary tale. While there are still many unanswered questions surrounding the largest documented natural die-off of cod in Newfoundland waters, federal researchers at the time concluded that seals weren't the culprit. Why the fish didn't adapt to the cold temperature is still a mystery, and the subject of further study by DFO scientists. But perhaps the answer lies in fact that collapsed populations are far more vulnerable to changes in their environment than healthy ones.
Meantime, Aldworth says it's easy to blame seals for the failure of the cod stocks to recover, just as seals were wrongly blamed for the Smith Sound die-off. But, she says, a massive $35 million cull on Sable Island can't be justified.
"This is clearly the Canadian government responding to immense political pressure from the fishing industry lobby," Aldworth says, adding it's unfortunate that DFO is investing time and money studying the feasibility of a massive seal cull on Sable Island in the absence of any evidence that it would restore the cod stocks, benefit the marine ecosystem or even reduce the transmission of parasites.
"There is evidence to suggest that the destructive fishing practices that continue today are responsible for fish stocks' lack of abundance and for the lack of recovery of those fish stocks," she says. "Scapegoating seals is not going to solve the problem."