04 Aug

What’s a weir?

In the first photos I posted from our trip to Redoubt Lake, I included this one of Mama Bear, leading her cubs over one of the fish weirs.

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Now, I suppose that not everyone knows what a “weir” is. I didn’t really have much of an idea when I started this job, although I did get excited because I saw a reference to a “vortex weir” which sounds like something totally awesome. I still don’t know what a vortex weir is, but the one you see above is a “picket weir.” Essentially, it is a picket fence in the water.

The back side of the weir is supported by big wooden tripods. The front side is metal poles, or pickets, which are threaded through two or three layers of framing to hold them in place. Since they hold up with bears walking across them, you can see that it’s a pretty sturdy structure.

Weir from the backside. Orange-pink bits below the weir in the foreground are salmon carcasses discarded by the bears.

Weir from the backside.
Orange-pink bits below the weir in the foreground are salmon carcasses discarded by the bears.

The advantage of the pickets, since they slide up and down, is that they can follow the contours of the bottom of the stream. The bottom of the pickets are covered with sandbags, which hold them down and cover any gaps, making it “fish-tight.”

Since all the returning salmon want to go upstream, or, at Redoubt Lake, up the falls and into the lake, they get backed up behind the weir. (That’s why the bears are there.) The Forest Service staff who are spending the summer working at the weir pull up the pickets to create gaps and let the fish through, counting every one.

Jon counting fish as they pass through the weir

Jon counting fish as they pass through the weir

Most of the fish get through with no hassle, but 10% of the fish that go through find themselves inside a fish trap, and become research subjects.

Laura nets a fish in the trap.

Laura nets a fish in the trap.

Since the bears are sloshing around in the water by the weir, and the water is always pushing to get through and down the falls, they check the weir to make sure it is still fish-tight.

Not a corpse - just Joe in a drysuit, snorkeling along the weir and checking the sandbags.

Not a corpse – just Joe in a drysuit, snorkeling along the weir and checking the sandbags.

It turns out to be pretty hard to take a picture of someone snorkeling in which they don’t look like dead body, so you might get a better idea from some of the video taken by Elizabeth, the intern working with me.

We’re talking and making noise so that the bears know where are while we’re sitting on the weir and counting fish. On the right you can see Jon standing on top of a log; he’s looking around the corner at the second weir, and then blowing an airhorn to tell the bears they can’t start fishing over there because we’re still around. In the background noise, first I am translating a Russian folksong which I’ve just finished singing, and then later starting to sing the only other Russian song I know. Not captured on this video is my exciting rendition of Angel from Montgomery.

27 Jul

Dead Whale Tales

On our way to Redoubt Lake, we made a little detour to check out this dead whale. It was a gray whale, which died and washed up in March or so. It originally washed up closer to the town of Sitka, but was towed to this location, further from people’s houses.

As you can tell, it has been dead for some time and is an advanced state of decomposition. Large portions of it had melted into piles of goo. As you might imagine, it smelled terrible!


But if you think that’s gross, imagine this image. The fellow we were with said when they cut it open for the necropsy, they unleashed a veritable river of blood. And one of my Forest Service supervisors told me he was once involved in towing a whale corpse from one location to another. When they approached that one in the boat, first, he said you started gagging a quarter of a mile away, and, second, they could see bubbles in the water, from gases escaping out of the blowhole. Yum!

Since it’s a giant smelly pile of meat, maybe you guessed that a whale carcass is a the sort of thing that attracts bears. In fact, the attraction is so well know that earlier in the year there were hunters who came out and shot a brown bear. You can see the bear’s skeleton in the foreground; the hunters only took the head with them. You can also see that Joe’s carrying his rifle in case any other bears come by for a snack.


Perhaps that unlucky bear was the one spotted in June by folks who went on a boat tour with the Sitka Conservation Society.