At a marina near Desolation Sound last summer, a school of small fish were busily swarming a jellyfish, biting off and eating bits of it, right beside the dock. I’d never seen a fish (or any animal, for that matter) eating a jellyfish, and nor had the other people who stopped to watch.
Murphy’s Law prevailed, so by the time I’d fetched my camera from our boat, the fish had darted off, leaving one lone individual whose resolve seemed to have vanished along with his buddies. So you’ll have to take my word for it: the large chunk missing from the jellyfish in the photo above was removed by a school of fish that included this little guy.
Since then I have learned that very few creatures eat jellyfish: the Leatherback turtle (a reptile), the Northern fulmar (a bird) and the Ocean sunfish (a fish, but a large one) are among the only known “medusivores”. I’ve been unable to find any mention of small fish in the Pacific Ocean eating jellyfish.
However, several articles in 2010 discussed the exciting (at least to marine biologists) news that jellyfish had been discovered to comprise up to a third of the diet of the Bearded goby, a small fish in the South Atlantic. This suggests that Bearded gobies are successfully adapting to some of the impacts of climate change, including the increasing number of jellyfish in the world’s oceans. (Here’s an interesting article about the findings and their significance.)
There are over 2000 species of gobies worldwide, and though I can’t be certain (and am happy to be corrected by more knowledgeable readers), I think my little fish last summer were likely Black-eye goby, one of our region’s three native species.
If so, could I have been witnessing some of the first evidence, here in the Pacific Northwest, that gobies are adapting to some of the impacts of climate change?
Now that would be exciting news, even if it is a lot to digest.