Tuesday’s (September 29) sighting of a gray whale swimming and possibly feeding right off the Stanley Park Seawall brings recent sightings up to three in that area.

It isn’t clear if it is the same whale or different whales in the widely reported incidents since August 12. One whale, perhaps the same animal each time, was observed for days in the same area in English Bay, sometimes travelling into Burrard Inlet and off West Vancouver’s Ambleside Beach.

Are these sightings so close together a sign that whales are finally coming back to Vancouver waters after decades of relatively stringent pollution controls? Or are they indicative of the successful rebuilding of stocks after the end of commercial whaling in our waters in 1967? (The gray whale itself received complete protection from the International Whaling Commission in 1947.)

It’s hard to say. There's no doubt the presence of large marine mammals is a vote of confidence in an area's ecological health. Sporadic appearances of mobs of feeding Pacific white-sided dolphins in Howe Sound in recent years can be attributed, at least partly, to the efforts to renew the herring populations there, as well as the closure of the Woodfibre mill and the Brtitannia mine.

And gray whale stocks, certainly, are the big success story on the eastern North Pacific coast, numbering about 20,000 today after almost being wiped out in the past century. The pre–commercial whaling estimate of Pacific North American grays is about 27,000. (Humpback whales are undergoing a similarly heartening return to pre-whaling levels locally and in the North Pacific.)

The filter-feeding species migrates past B.C. from its calving grounds in Baja California, Mexico, every spring on the way to summer and fall feeding waters in northern Alaska’s Bering, Chukchi, and Western Beaufort seas, where they gorge on the large zooplankton crustacean blooms. The whales come back along the same route late in the year, and the return trip of 16,000 to 22,000 kilometres is the longest migration of any marine mammal on Earth (a record shared by the humpback).

Back in January 2007, a tugboat operator spotted a gray whale swimming in the Fraser River near the Port Mann Bridge. Three years later, a gray whale seen feeding at the mouth of the Squamish River was declared to be the first in Howe Sound in a century. A few days after that, Vancouver’s False Creek hosted a gray, between the Granville and Burrard bridges.

Those sightings sparked lots of media (and scientific) interest, both in Vancouver and across Canada. With adult specimens of Eschrichtius robustus at almost 15 metres in length and weighing up to 35 tonnes, they are a spectacular sight.

Now, though, the frequency of appearances seems almost to have induced a sense of blasé detachment in locals. The TV stations don't always lead off the evening news with whale video clips these days. The Vancouver Police Department’s maritime patrol, which attends such sightings in its jurisdiction when possible, even tweeted on September 30 that such encounters were “becoming a regular gig”.

So, should Vancouverites get used to the idea of seeing gray whales in neighbouring waters all the time now?

Possibly. Especially if what we are seeing lately is what cetacean researchers refer to as a “seasonal resident” whale.

What we might be witnessing is the adoption of Vancouver by a gray whale that has voluntarily left its migrating fellows in order to settle down for a while in an area that appears to have a stable, sufficient supply of food, in its case small fish and invertebrates such as worms, mysis shrimp, or crab larvae, depending on what is available.

From California to southern Alaska, about 200 to 300 of such grays hang out in selected waters for about three seasons every year, linking up with their fellows in winter in Mexico, where they live off their blubber until returning to their feeding grounds again.

But those months of near-privation make it necessary that the whales store enough energy in their blubber during their feeding months to survive the migration. And climate change might or might not be playing a part in terms of affecting their feed in the north Pacific. Could a fear of starvation be causing some to abandon migration to hole up along the coast if sufficient food supplies are found?

A varying number of them—some scientists think as many as 200—stay off the northern California and Oregon coast between June and October, with a group of about 40 making Oregon's Depoe Bay area their summer home. A bunch of about a dozen turn up around Washington state’s Whidby Island every spring and summer, with about another 50 preferring Puget Sound's waters. Such resident whales have spawned a lucrative seasonal whale-watching industry (worth almost US$30 million annually in Oregon alone).

As many as 80 of them are estimated to stop in shallow B.C. coastal waters every year. Some are these are well known around the towns of Tofino and Ucluelet on the west coast of Vancouver Island near Long Beach, often in Clayoquot Sound.

It isn’t known exactly why such whales behave the way they do, but plentiful food is probably the reason.

Very accurate photo-identification methods mean that researchers have a good grasp on which seasonal resident whales return to the waters of their choice each year, so researchers and conservationists should know soon if the recent appearances have been of the same cetacean.

And who knows if seasonal residents attract others once they have adopted an area? If one whale becomes a half-dozen or a dozen cetaceans returning religiously for seven or more months every year, there could be a stampede for licences to operate whale-watching outfits in English Bay and surrounding waters. This would bring attendant safety problems regarding the busy marine traffic in Vancouver's inner and outer harbours, both commercial and recreational, but that would probably be a problem most people would love to have.

And because grays are thought to live as long as 50 to 60 years (exact lifespans are unknown), if we are seeing the beginning of an English Bay–Salish Sea regular seasonal visitor, expect local media to anthropomorphize this pioneering marine mammal by giving it a name and dutifully reporting its every appearance.

Just don’t expect the same fanfare generated by previous years' intermittent and unpredictable cameos.

(And if you want to get the jump on the inevitable Vancouver Aquarium name-the-whale contest if the visitor does turn out to be a new seasonal resident, leave your suggestion in a comment below this story.)