The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note of any observations you have made of the world around you. Rain, sun, wind...insects, birds, flowers...meteorites, rocks...seasonal changes...all are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
September 2013 San Juan Channel, Pacific Northwest
"The sea lions are back." That was the word circulating on the island recently, so I grabbed my foul weather gear and camera, and hiked out to see them. This was a stormy day, autumn having crashed into the Pacific Northwest early this year, with thunder and lightning, but sea lions are pretty exciting too. San Juan Channel is a good spot to find them, especially at Cattle Point Narrows, where tidal currents race through the constricted channel between Lopez and San Juan Islands, at times as powerfully as 5 knots.
The lighthouse across the way is at Cattle Point at the very south end of San Juan Island. It's less than a mile from where I'm standing, and that water is over 500 feet deep. Considering that as much as 10 vertical feet of ocean has to move through here in 6 hours, you can understand why it looks like a river when the tide is running. There are reefs on both sides too. These in front of me are called Deadman rocks. The tide here runs even swifter, with whirlpools and waves, very hazardous for sailors, needless to say.
But what makes the sea dangerous to people is exactly what makes it attractive to animals hunting for fish. When the tide is slack, fish hide out. When it runs, the fish come out. So do the fish-hunters.
Harbor seals (Phoca vitulina) live here all year. Any day I come out here I'll see them hauled out on the rocks and swimming around, their growls and grunts carrying across the water. It's high tide right now so many seals are balanced on the tops of rocks, sunning in this break between showers.
Dry fur is lighter. You can tell which seals have been snoozing for a while. Some of these fellows are watching me, even though they are quite safe over there.
Today I was hoping to see Steller sea lions
too, who come into the Salish Sea for the winter. They are huge animals, 10 feet long, easily distinguished from the seals, half that length. Here's one cruising along at the surface. See how big it is compared to the seals hauled out beyond it! Their fur is also a uniform reddish-blond, unlike the shades of patterned gray of the seals.
While I watched, the tide began to turn. Within half an hour it was running fast. The ebb tide pours out to the left from this vantage. The sea lions began fishing in earnest.
There were at least three I could see at one time, though probably more since they were all intermittently underwater. All these sea lions are males, come to feed prodigiously over the winter, before they rejoin the females at rookeries in Oregon, northern California and Canada. During breeding season males don't eat for months while they fight for territory and their harems. It's quite peaceful at this time of year though, feeding grounds being neutral territory.
More after the tangle of bull kelp.
Like many other marine mammals, Steller sea lion numbers plummeted in the 20th century after rampant hunting, and overfishing depleted food sources. Populations have recovered somewhat since the Marine Mammal Protection Act of 1972. The 2009 U.S. ban on West coast krill-fishing is intended to provide more food for marine species across the board, in recognition of the fact that large visible animals like whales and salmon depend on the tiny crustaceans. The marine food web is complex, and our understanding of it too often simplistic. For example, fishermen generally have a poor opinion of seals and sea lions, seeing them as competitors for commercially valuable salmon. However field research (scraping poop off rocks and analyzing its contents) shows these mammals are actually opportunistic hunters, eating whatever is most abundant at the moment, typically herring, hake, pollock, dogfish and salmon. In cases where seals have been killed off, as in the Copper River delta of Alaska in the 1960s, the result was not more salmon for fishermen, but fewer salmon, and the failure of the razor-clam fishery. Seals eat Starry Flounders, predators of Razor Clams. Seals also consume Hake, which prey on juvenile salmon. To me, seeing all these seals and sea lions is a sign of a more robust ecosystem.
These sea lions would take several deep breaths and then dive for a few minutes, coming up with small fish, likely herring or sand lance. This surprised me somewhat since we've had a big run of Humpback salmon, or Pinks (Oncorhynchus gorbusha
), this fall, a blip of good fortune, likely the result of cooler La Nina waters over the last two years (these are the smallest and most abundant of our 5 species of salmon; unfortunately other species are on a steady downward trend, especially the Chinooks, or King salmon (O. tshawytscha
), which our resident orcas depend on). I'll go out on another occasion and see if they're coming up from their dives with any Humpies.
A flock of about 60 Heermann's gulls (Larus heermanni) got into the action too, following the sea lions, swooping down to catch scraps. I could tell where a sea lion was about to surface by watching the gulls. See the splash:
spend the summer and fall in the Salish Sea feasting on our abundant fish too, before heading south to Mexico for breeding. You rarely see them in parking lots and garbage dumps. Their vivid orange bill and sharply contrasting plumage are especially dramatic in a big flock like this one chasing the sea lions.
Once the tide started running in earnest, seals began to slide into the water, mostly diving along the steep walls in the kelp beds. The gulls followed them too. Can you see the two seals in this photo?
Straight down below the bluff where I was standing a seal surfaced, and rolled over, swimming upside down for a bit - a nice trick, getting a good look underwater while still breathing above the surface - then glided along the wall, sleekly navigating the tangle of kelp and reef. Ungainly on land, these creatures have such powerful grace in the sea.
Other wildlife was out feeding too, in their own ways. Saw a Harlequin duck diving in the current along the wall, hunting mollusks and crustaceans in the reef. Harlequins breed up in the mountains, and then migrate down to our rough coastal waters for the winter. Also watched a Great Blue Heron perching lightly on a mat of bull kelp, ready to snatch up small fish hiding in the tangle.
It was so cool to stand there watching all this activity, but in a while the western sky began to darken ominously. The little break in the storm was blowing past me, and it was getting chilly, so I hiked back through the woods. The squall hit just as I got to my car. I couldn't help but think about the seals and sea lions and birds out there, at home in the thunder and lightning and rain and rushing current.
The Daily Bucket is open for your observations of nature. Stormy weather, signs of fall, cool wildlife? All notes are welcome.
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