Hood Canal never disappoints me.
We’re in year 2 of our herring habitat study, asking whether Puget Sound herring populations are limited by the availability of spawning habitat. Does egg mortality vary by spawning substrate? Is eelgrass a better place to put your eggs than, say, invasive brown algae? In year 1, we learned that egg mortality was the same across spawning substrate types: eelgrass, invasive brown algae, red algae — you name it. Substrate type doesn’t matter. What does matter, we found, is where that substrate occurs. We found greater differences in egg mortality among spawning sites — Elliott Bay versus, say, Hood Canal — than among spawning habitat within sites.
This year, we’re looking closely at why herring egg survival varies among spawning sites. Is it shoreline development? Is it water quality? Is it predation? This last one – the predation question – is by far the most fun to sample! We’re dropping cages on top of herring spawn and comparing egg loss rates (the number of eggs found on day 1 minus the number of eggs found on day 10, for example) inside and outside of cages. Big cages. Big old sablefish traps, in fact, thanks to our collaboration with NOAA Fisheries.
So last week we returned to our sampling site in Quilcene Bay on Hood Canal, following a tip from the Department of Fish & Wildlife that the herring were going nuts. And indeed they were, along with everything else!
The sun came out as our boat arrived on the spawning site, which had the tell-tale sign that eggs were in the water: birds. Hundreds of egg-eating birds: scoters, pigeon guillemots, mergansers, grebes. And the fish-eating types, too: cormorants and gulls.
We soon discovered why: the spawning herring were still on site, 2 days after the report came in. Which meant there were both eggs and fish available for feasting, and so we were treated to a real Lion Country Safari, Puget Sound style. In addition to the diving birds and gulls, we counted 24 bald eagles on site, chasing after herring when they came to the surface.
Invertebrates were chowing down, too. This fella came on board attached to some red algae:
I know it’s not cool, but I have to confess that what made me the happiest was watching no fewer than 2 dozen California sea lions chasing after herring, forcing the fish to flip out of the water in an effort to escape predation. [As evidence of exactly how uncool I behave when I see wildlife action, check out this video. Listen at your own peril! http://youtu.be/_0-IPW6_QvE] It was pretty amazing watching the gulls, eagles and sea lions chase after and fight over the fish. The divers were kind enough to bring me evidence of the massacre!
After gorging on fatty forage fish, the sea lions gathered in rafts out in deeper waters and basked, raising their flippers in the air. Not exactly sure what’s going on there, but they seemed fat, happy, and lazy.
As one colleague said to me after hearing about my day: “I guess the Sound isn’t toast after all.”
Plus, none of the sea stars we saw showed signs of wasting syndrome.
I gotta say, it was a good day.