Murre chicks take to the water when they’re barely three weeks old, too young to fly or dive. Their fathers go with them and stay by their side for months, feeding them and teaching them to fish while their mothers, which have made a heavy caloric investment in producing eggs, go off by themselves to recover. Parental devotion and the equal division of labor pay dividends. The reproductive success rate of Farallon murres is extremely high, typically above seventy percent, and they’re one of the most abundant breeding seabirds in North America. Huge though it was, the colony that Warzybok and I were visiting held less than five percent of the islands’ murres.
The murre population today represents a provisionally happy ending to a long, sad story. Two hundred years ago, when Russian hunters began wiping out Californian fur seals, as many as three million murres bred in the Farallons. In 1849, when the Gold Rush made San Francisco a boomtown, the islands became an inviting target for a city without a poultry industry. By 1851, the Farallone Egg Company was gathering half a million murre eggs a year for sale to bakeries and restaurants. Its eggers arrived by boat in the spring, crushed the eggs that had already been laid, and proceeded to collect every freshly laid one. Over the next half century, at least fourteen million murre eggs were harvested on the Farallons. The birds’ fidelity to their nest sites kept them coming back, year after year, to be robbed of the objects of their devotion.
By 1910, fewer than twenty thousand murres remained on the main island. Even after egging stopped, they fell victim to the cats and dogs introduced by the keepers of the island’s lighthouse, and large numbers were killed at sea by oil flushed from the tanks of ships entering San Francisco Bay. The murre population didn’t seriously recover until after 1969, when the main island became a federal wildlife refuge. And then, in the early 1980s, the population plunged again.
The problem was the indiscriminate fishing method known as gill-netting. Hauling a huge net to the surface of the ocean sweeps up not only the target fish but porpoises, otters, turtles, and diving seabirds. Today, globally, at least 400,000 seabirds are killed every year in gill nets—murres and puffins and diving-ducks in northern waters, penguins and diving-petrels off the coast of South America. The annual worldwide toll on murres alone may exceed the 146,000 killed in the 1989 Exxon Valdez oil spill, the most destructive spill in history.
Beginning in the mid-1980s, many American states, including California, took note of the ecological havoc and imposed severe restrictions or outright bans on gill-netting. The result, in the Farallons, was an immediate surge in seabird numbers. In the past fifteen years, safe from gill-netting, and free to do what they do, the murres have quadrupled their population. The only threat to their survival in the Farallons now is the disruption of their food source by climate change or overfishing.
Pete Warzybok, perched in the blind, was writing down the species of fish that the murres in his study plot brought back to their nests. To a California fisherman asked to share the ocean’s bounty with seabirds—Farallon murres consume more than 50,000 metric tons of fish every summer—the argument for murre conservation isn’t just ethical or aesthetic. The birds that Warzybok studies function like airborne fishery-monitoring devices, a fleet of living research drones. They scour thousands of square miles of ocean and are expert at finding where the food is. Using only binoculars and a notebook, Warzybok can gather better data about current anchovy and rockfish populations, for much less money, than California’s fishery managers can gather from a boat.
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Farallon murres are the lucky ones. They’ve survived most of the major threats to seabirds, and a case can be made for their economic utility. Elsewhere, globally, in the past sixty years, the overall seabird population is estimated to have fallen by seventy percent. This number is even worse than it sounds, because a disproportionate number of seabird species are at risk of extinction. Of the world’s 350 or so seabirds, a larger percentage is listed as endangered or threatened than of any comparable group of birds. Parrots, as a group, have troubles of their own, but they’re also widely admired. Game birds are valuable to hunters; eagles and other raptors are conspicuous and iconic. Seabirds breed on remote, forbidding islands and spend most of their lives in waters inhospitable to us. If they disappeared entirely, how many people would even notice?
Imagine a young albatross in the South Atlantic Ocean. It’s following the circumpolar winds, gliding five hundred miles a day on its ten-foot wingspan, using its nose to track the smell of fish or squid or crustraceans near the water’s surface. Often the best place to find food is in the wake of a deepwater fishing vessel. The young albatross glides in circles around a trawler and eyes the chaos of smaller seabirds tussling over the fish scraps thrown overboard. When it plunges into the scrum, it brings a size advantage: a massive bill and a wingspan that announces, I am huge! The other birds scatter, but as the albatross hits the water something goes terribly wrong. Its outstretched wings have wrapped around the cable of the trawler’s net, which drags it under and swiftly pulls it deeper. No one sees this happen. No one is out on the cold, choppy water except the trawler’s crew. Even if the crew had time to be looking, the bird has disappeared in the blink of an eye, and its dead body won’t float to the surface until the ship has moved on.
Every year, thousands of albatrosses are killed invisibly by trawlers. Tens of thousands more die on the hooks of long-line fishing vessels, along with even greater numbers of petrels and shearwaters. Accidental death in the world’s fisheries is one of the two most grievous threats that seabirds face, and it’s a tough one to address, because deepwater fishing boats typically operate under intense financial pressure and minimal oversight. Only a few countries seriously regulate their fleets’ seabird bycatch.
In one of those countries, South Africa, I met a successful long-line tuna-boat captain named Deon van Antwerpen. With me, at a small harbor in Cape Town, was Ross Wanless, a biologist who manages the seabird conservation program of BirdLife South Africa. Wanless had come to the harbor to hear about the problems that Van Antwerpen was having with the government’s seabird regulations. Van Antwerpen, a beefy and voluble man, gestured unhappily toward a basket of pale green fishing-line weights at the back of his vessel. “We’ve lost three thousand of these things,” he said.
Long-line fishing kills albatrosses differently than trawling does. A smaller seabird dives down and brings a baited hook to the surface and tries to pull the bait off, and then an albatross barges in and swallows the whole thing, hooking itself and drowning. One solution is to weight the line, so that the baited hook quickly sinks out of reach of the birds. But a bare metal sinker can become a bullet to a crew member’s forehead when a hundred-pound tuna is hauled in and the line recoils. BirdLife recommends sinkers with a loosely attached casing of luminescent plastic (light attracts fish), and Van Antwerpen had been eager to try them on his vessel. “Every bird I catch,” he said to Wanless, “is potentially a fish I didn’t catch. But you need to get legislation that’s practical. If you don’t, then most guys will just ignore it.”
There ensued an intricate discussion between an exceptionally conscientious boat owner and a conservationist whose goal is to bring bird-safe methods to the entire world’s deep-sea fishing fleet. Van Antwerpen’s chief complaint with the plastic sinkers was that BirdLife wanted them too close to the baited hook—“If a shark snaps the line, we lose the sinker.” Would it be okay if he increased the separation between sinker and hook to four meters? Wanless frowned and pointed out that this would make the hook sink too slowly to protect seabirds. But maybe increasing the weight of the sinker would compensate for a greater separation? Van Antwerpen said he’d be happy to do the experiment—he really didn’t want to catch albatrosses. He just wanted to catch tuna without losing all his sinkers.
Fishing vessels can further reduce seabird bycatch by dragging a “bird-scaring” line, which consists of a brightly tasseled rope with a plastic cone at the end of it. Bird-scaring lines are inexp
ensive, easy to use, and highly effective at keeping birds out of a vessel’s wake. A trawler, by using only a bird-scaring line, can reduce albatross mortality by as much as ninety-nine percent. Because a long-line vessel’s hooks remain close to the surface beyond the bird-scaring line, South Africa requires it to take one additional protective measure, either weighting its lines or setting them after dark, when the birds are less active and can’t see the bait.
Wanless and his wife, Andrea Angel, who is the leader of BirdLife’s Albatross Task Force, have been working with South Africa’s government and fishing fleet for more than a decade. Any commercial vessel fishing in South African waters now has to practice seabird-bycatch mitigation, and Wanless and Angel are attempting to forge relationships with every skipper in the country’s fleet. “The way to achieve something,” Wanless told me, “is not to present a fancy technical solution but to engage with human beings.” As a result of his and Angel’s efforts, the annual toll on seabirds in South Africa has fallen from an estimated 35,000 in 2006 to as few as 3,000 today. The trawler fleet in neighboring Namibia has reduced its bycatch from 20,000 to 1,000.
But protecting seabirds takes more than regulations. It also requires independent monitoring of fishing vessels and, ideally, a financial incentive for the industry to reduce seabird bycatch. Although long-liners have one straightforward reason to catch fewer birds—“They’d rather catch ten-thousand-dollar bills, which is what a bluefin tuna represents,” Wanless said—a potentially stronger incentive is the market for sustainably harvested fish. Pursuit of this premium market, particularly in Europe, has led much of South Africa’s fleet to pay to put an observer on each of its ships, to ensure compliance with bycatch rules. Without an observer on board, even a captain like Van Antwerpen may sometimes break the rules.
The best way for a government to ensure compliance is to mandate that every vessel be outfitted with a digital camera to monitor its catch and bycatch. When Australia did this with its tropical tuna-fishing fleet, in 2016, ship captains placed panicked calls to Australian regulators, asking where they could buy bird-scaring lines. “Once there’s a camera on board, the game’s over,” Wanless said. “You’re risking losing your license for failing to buy a hundred dollars’ worth of gear.”
Another promising technological advance is the Hookpod, which Wanless calls “the silver bullet.” It consists of a hard plastic case that snaps around a baited hook, protecting the bait from birds and birds from the hook, and that doesn’t spring open until it has sunk to a safe depth. The Hookpod isn’t as cheap as a hook and a sinker, but it’s cheap compared with the value of tuna, and it comes with an LED that attracts them. “What we like about the Hookpod,” Van Antwerpen told me, “is that we put six of them in the water and caught fish with two of them, because of the light.”
It is theoretically possible, by making the Hookpod standard equipment on all long-line vessels, and by requiring all trawlers to run bird-scaring lines, and by simply banning gill-net fishing (as South Africa has done), to render the world’s oceans safe for seabirds. For now, though, the global situation remains atrocious. Wanless and Angel have expanded their outreach to the fisheries of South America, Korea, and Indonesia, with not altogether discouraging results, but the fleets of China and Taiwan, which together account for two-thirds of fishing vessels on the high seas, operate with little or no regard for seabird mortality, and they sell their catch in markets mostly indifferent to sustainability. Wanless estimates that 300,000 seabirds, including 100,000 albatrosses, continue to be killed annually by long-liners alone. This is hard enough on the abundant species, like Sooty Shearwaters. But many species of albatross, which are slow to reach maturity and typically breed only in alternate years, are threatened with extinction. And, as harmful as modern fishing practices are, there’s an even deadlier threat that seabirds face.
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Gough Island, a twenty-five-square-mile mass of volcanic rock in the South Atlantic Ocean, is home to millions of breeding seabirds, including the entire world population of the Atlantic Petrel and all but a few pairs of the critically endangered Tristan Albatross. Ross Wanless first went to Gough in 2003, as a doctoral candidate, after other researchers had reported that alarmingly few petrels and albatrosses were fledging chicks. It was known that rats and cats, which humans have introduced on islands all over the world, prey heavily on seabirds. But there were no rats or cats on Gough, only mice. Using video cameras and infrared lights, Wanless recorded what the mice were doing to the petrel chicks. “The sun went down,” he said, “and a mouse came out in the petrel burrow. It hesitated and then started nibbling on the chick. Other mice came, and I witnessed this insane, disgusting attack. As the blood started to flow, the mice got more and more excited. At times, there were four or five of them competing for the wound, lapping up blood and going inside to eat the chick’s internal organs.”
Having evolved without terrestrial predators, seabirds have no defense against mice. A petrel in its inky-dark burrow can’t even see what’s happening to its chick, and an albatross on its nest lacks the instinct to recognize mice as a threat. In 2004, Wanless recorded 1,353 breeding failures among Gough’s Tristan Albatrosses, most of them from mice predation, and only about 500 successes; in more recent years, the rate of breeding failure has been as high as ninety percent. Among all species of seabird on Gough, mice now kill two million chicks every year, and many of these species are also losing adults in the fisheries. Annual mortality among adult Tristan Albatrosses at sea has risen to ten percent—more than triple the rate of natural mortality. Ten percent adult mortality plus ninety percent breeding failure is a formula for extinction.
The calamitous decline in seabird populations has many causes. Overfishing of anchovies and other small prey fish directly deprives penguins and gannets and puffins of the energy they need to reproduce. Overfishing of tuna, schools of which drive smaller fish to the ocean’s surface, can make it more difficult for shearwaters and petrels to forage. Climate change, which alters ocean currents, already appears to be causing breeding failure among Iceland’s puffins, and birds that nest on low-lying islands are vulnerable to rising sea levels. Plastic pollution, particularly in the Pacific Ocean, is clogging the guts of seabirds and leaving them hungry for real food. And the resurgence of marine mammal populations—in other respects, an environmental success story—has resulted in more seals to eat young penguins, more sea lions to crowd cormorants out of their breeding sites, and more whales to compete with diving birds for prey.
The number-one threat to seabirds, however, is introduced predators: rats, cats, and mice overrunning the islands where they breed. This is the bad news. The good news is that invasive species are a problem with achievable solutions. Organizations such as Island Conservation, a nonprofit based in California, have perfected the use of helicopters and GIS technology to target predators with mammal-specific poisoned bait. Animal lovers may grieve at the mass killing of small furry mammals, but human beings have an even greater responsibility to the species they’ve threatened with extinction, however inadvertently, by introducing predators.
The most ambitious rodent-eradication effort to date was mounted by the South Georgia Heritage Trust. South Georgia island, which lies nine hundred miles from the Antarctic Peninsula, is the breeding ground of perhaps thirty million seabirds; without rats and mice, the island could easily host three times that number. From 2011 to 2015, at a cost of more than $10 million, three helicopters traversed every ice-free area on South Georgia, dropping bait. No living rat or mouse has been detected since 2015.
Similar efforts are now planned for Gough Island, in 2019, and for South Africa’s Marion Island in 2020. Mice came to Marion with whaling and sealing vessels in the nineteenth century. In the 1940s, the South African government introduced cats to control them, and the cats quickly went feral. Instead of killing mice, they proceeded to decimate the smaller seabird species nesting on the island. (“Mice know exactly what a cat is,” Ross
Wanless explained. “Seabirds don’t.”) Marion’s seabird populations were expected to recover as soon as the last cats were removed from it, in 1991, but they didn’t. “The mice are the only explanation,” Wanless said.
Seabirds are a poignant combination of extreme vulnerability and extreme toughness. A twenty-pound Tristan Albatross can’t stop a one-ounce mouse from eating its young, and yet it thrives in frigid saltwater and brutal winds and can bully a large gull. Because of its longevity, it may survive twenty years of breeding failure and still produce chicks, once the threat to its nest is eliminated. “Seabirds respond well to restoration,” Nick Holmes, the science director at Island Conservation, told me. “Addressing the terrestrial threat bolsters their resistance to all the other threats.” When Island Conservation and its partners eliminated rats from California’s Anacapa Island, south of Santa Barbara, the hatching success rate of Scripps’s Murrelet (a small cousin of the Common Murre) immediately jumped from thirty percent to eighty-five percent. The murrelets are now secure on Anacapa, and Ashy Storm Petrels have been recorded breeding there for the first time.
The End of the End of the Earth Page 13