Marine mammals return to Strait of Georgia
Dotted across a map of coastal B.C., a handful of place names tell a cryptic and almost forgotten story. Whaletown, on bucolic Cortes Island. Whaling Station Bay, a semicircular sweep of white sand on the northeast corner of Hornby Island. The Ballenas Islands, a pair of uninhabited islets readily visible from the ferries that plow daily between Nanaimo and Horseshoe Bay. All point to a glorious past, a time when the Strait of Georgia was a paradise for many species of whale, along with harbour seals, sea lions, and fish beyond number.
They also hint at a different, bloodier time, when B.C. was briefly home to a thriving trade in whale oil, meat, and baleen.
“At the turn of the last century, it was quite common for people to row out in English Bay and watch the humpbacks breaching,” says Andrew Trites, on the line from his office at UBC, where he’s director of the Fisheries Centre’s marine-mammal research unit. “And then there was a whaling station set up over near Nanaimo, and within only a few years they managed to kill all the humpbacks that used to come to the Strait of Georgia.”
This wasn’t the brutal but easily romanticized whaling of Herman Melville’s Moby Dick. Instead, it was a modern, industrialized fishery, with motorboats and rocket-propelled harpoons, and by 1910 it had extirpated the Strait’s humpbacks and grey whales. Some thought they’d never return.
Recent months have shown otherwise, however, with several high-profile cetacean sightings giving hope to amateur whale watchers and veteran marine biologists alike.
“We’ve always had grey whales and humpbacks and even Pacific white-sided dolphins kind of poke their heads into Georgia Strait,” says Paul Cottrell, regional marine mammal coordinator for Fisheries and Oceans Canada (FOC). He’s checking in from Bedwell Harbour on South Pender Island, where he’s overseeing a project designed to identify noise-pollution threats to southern resident orcas, an endangered subspecies now thought to number just 88. “But what’s unique about the last year is that animals from these different species were staying.”
Cottrell cites the pod of approximately 100 Pacific white-sided dolphins that spent several days feeding in Howe Sound this past May, a grey whale many urban residents saw feeding in False Creek at about the same time, and two more greys that have become long-term occupants of the waters off Victoria and Sechelt.
“We do have resident grey whales along the west coast of Vancouver Island and the central coast up north,” he notes, “but we’re seeing grey whales maybe becoming residents of these other areas, which is really interesting. Of course, they’re just occupying areas they used to occupy. But they’re staying because there’s a food source there, which indicates a healthy aquatic ecosystem.”
If this sounds like a positive development for our embattled marine environment, it probably is. And it’s not just greys, humpbacks, and dolphins that are making a comeback. Although chinook-salmon–eating southern resident orcas are just barely holding their own, their carnivorous transient kin in the Strait of Georgia have experienced a resurgence that is surprising even whale specialists.
“When we started studying killer whales in the mid-’70s in Georgia Strait, these transients were extremely rare,” says FOC biologist John Ford, speaking by cellphone from Klemtu, where he’s researching fin whale populations in B.C.’s northern waters. “Over the years, the numbers [of transient orcas] have increased substantially. The population has done really well: their numbers have gone from about 25 animals in the early ’70s to about 10 times that in our study area. There’s a combination of really good survival in the population and immigration into the area, to the point that transient killer whales are a very common feature in the ecosystem of Georgia Strait. They’re present pretty much on a daily basis.”
The inference is that populations of harbour seals and Steller sea lions—preferred prey for transient orcas—are also healthy, as indeed they are. The larger of the two pinniped species has suffered a calamitous population crash in the western portion of its range, from Prince William Sound across to northern Japan. Here, though, Steller populations are on the rise, and although harbour seals in the strait have topped out at about 40,000 individuals from a low of 3,800 in the 1970s, that’s on a par with the numbers that would have been present prior to European colonization.
It’s tempting to look for an ecosystem-based explanation for this comeback, but the answer is simpler than that: these days, apart from a few misguided fish-farm operators, no one is shooting seals or sea lions. Prior to their becoming protected species under the federal Fisheries Act in 1970, however, sea lions were fair game, and harbour seals had a bounty on their heads.
Also thanks to a hunting ban, we may see one of the largest of the pinnipeds, the northern elephant seal, make a return to these waters. Believed extinct in the 1880s, this ungainly and almost entirely aquatic animal has grown from a remnant population of approximately 100 individuals to the point where there are now more than 100,000 in the eastern Pacific—not including, of course, the dead full-grown male that washed up in Nanaimo’s Departure Bay in November 2008, apparently having been struck by a large seagoing vessel.
“After that happened,” Trites says, “I started getting various e-mails sent to me saying, ”˜You know, I saw an elephant seal.’ So they’ve probably been here for a while, but you don’t see a lot of them because, typically, they don’t haul out. And people’s accounts were basically like they’d just seen a sea monster—this massive head with a huge nose stuck out as they were walking along the beach or paddling a kayak.
“It’s not a common occurrence, but I think what we’re seeing in B.C. is animals coming back into an area that they traditionally fed in. And who knows? It’s conceivable that before the First Nations people were hunting, there may well have been breeding elephant seals in B.C. It’s not out of the question that we’re seeing them return to their normal range.”
It’s unlikely that many humans will resent this return to normality on the part of grey whales, humpbacks, and elephant seals. Harbour seals and Steller sea lions are another matter. There’s a reason why they were, and in some cases still are, hated by recreational and commercial fishers alike.
“Certain marine mammals, like seals, sea lions, and some whale species, are very curious,” says Lisa Spaven, who heads up the B.C. Marine Mammal Response Network, based at the Pacific Biological Station in Nanaimo. “And like garbage bears, they’re looking for ways to find their prey more easily, which can lead to increased interaction with fishing gear. Certain marine mammals are known for depredating, which means taking fish off lines, and that then becomes an issue—not only for the marine mammals in that they’re getting entangled, potentially, but also for the fishermen, because they’re having damage to or losing their gear, or losing their catch.”
When a happy pinniped swims off with the salmon a recreational angler was planning on having for dinner, it’s understandable that the aggrieved party might want to call for a renewal of the seal cull. Pressure is mounting on the government for just such an action, but that, Trites says, would be a mistake.
“One of the controversies that I see coming up over and over is, ”˜There’s too many harbour seals. We’ve got to get rid of them,’ ” he notes. “And that’s in the mistaken belief that it’s a fairly simple system, and that all the seals eat is salmon—that if we remove the seals, there’ll be more salmon. But like any problem that I’ve ever worked on, once you scratch below the surface you find out that it’s far more complicated than that.
“Just as an example, we don’t have any recent diet information, but what we know from the 1980s is that salmon made up four percent of the diet [of local harbour seals]. It’s hardly a ringing endorsement for seals eating all the salmon. The bigger items were herring at 32 percent and hake at 43 percent, and what’s interesting about this is that hake is the largest fish predator of salmon smolt. So it could be that while the seals do eat adult salmon, the fact that they eat more of the salmon predators means that they have a net positive effect on salmon returns.”
Even more complicated is the effect that global warming is having, not only on charismatic megafauna like humpbacks and orcas but on the self-effacing microfauna at the bottom of the food chain, the minute animals that ultimately help to feed us as well as pinnipeds and cetaceans.
“On the West Coast,” says FOC herring specialist Jaclyn Cleary, “there’s a pretty clear inverse relationship between sea-surface temperature and herring production. In warm years, when the sea-surface temperature is high, we tend to get more southern predators like hake. Last year, there was lots of Humboldt squid around. And those warm conditions also usually result in reduced availability of food—like lipid-rich copepods and euphausiids [krill]—for the herring stocks. But in the Strait of Georgia, those relationships are not as concrete.”
There’s more research that needs to be done, she suggests, including paleobiology—the use of ancient soil and midden strata to study historical patterns of animal distribution. Prof. Herb Maschner of the University of Idaho’s anthropology department is a pioneer in the field, having made some significant discoveries regarding Steller sea lion populations in Alaska. (One of his more controversial theories suggests that curtailing the Atka mackerel fishery in Alaska, as proposed by U.S. environmental groups, might actually hurt sea lions. Paleobiological data show that high mackerel populations coincide with low sea-lion density—the fish outcompete sea lions for food—while modern-day dietary studies suggest that juvenile Stellers can’t extract enough nutrition from mackerel to survive.)
“The problem is that nobody’s really tried to do what I do,” he says. “I’ve had millions of dollars in funding to do this in the [northern] Pacific, but nobody’s tried”¦in the Gulf [Strait] of Georgia, even though the middens are there.
“But what you can take from me, for your region of the world,” he continues, “is that if something is doing surprisingly well and hasn’t for a long time, it means something else we’re not noticing is doing surprisingly bad, and we’ve got to start paying attention to what that might be. If a certain set of species are all of a sudden doing great, it means somebody else is paying for it. And if you don’t know what that is yet, you have to look.”
But that will take money, and although the good news is that most marine-mammal species in the Strait of Georgia are thriving, the bad news is that research budgets are not.
“I come from a field that’s got more questions than answers, and the only way we’re going to answer these questions is by doing research. Without sound scientific information, you can’t make sound management decisions or social-policy decisions,” says Trites, who argues that while government scientists are doing valuable work, their political masters in Ottawa don’t see basic research as a priority.
“I mean, we can just look at the StatsCan example,” he says, citing the ongoing census controversy. “It’s almost like, ”˜We don’t need any information because we know, in our heart of hearts, how to make the right decision.’ And I think that’s a bit frightening.”
Especially, he adds, given that the twin problems of global warming and human overpopulation require hard decisions be made right now.
“Do we want a system where you can stand on your porch and look out and see a humpback whale or see dolphins frolicking or killer whales hunting harbour seals?” he asks. “Or would you like a system that’s clean on the surface but you see no marine mammals and no sea birds because we’ve used the sea as their competitors?
“There’s definitely a story here,” he adds, “and I don’t think any of us know what the final sentence will be.”