Small fish with jellyfish that has a chunk missing

A lot to bite off (click to enlarge).

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.

About Laurie MacBride, Eye on Environment

Photographer and writer focusing on nature and the environment

11 responses »

  1. dianeschuller.com says:

    what a very interesting phenomenon. Thanks for sharing this. I’m sure many species are adapting in this fast-changing environment of ours.

  2. Fred Bailey says:

    Laurie:
    One thing about the notion of global warming…. we’re starting to watch the world around us a lot more closely, and seeing things we’ve just never noticed before. In summer at Comox, the water is chock full of tiny moon jellies,billions of them, and some interestingly enough, have always fallen prey to the piling perch.
    Fred

    • Hi Fred, thanks for the comment. Interesting and yes, I agree, we do start to notice things that we may have overlooked before, once they become more relevant to us personally. But I’m guessing those perch were at best just trying out the moon jellies, because even such small jellyfish, like others in their class, have a defense system consisting of poisonous, stinging and barbed cells. These apparently deter almost all predators (other than the giant sunfish and the others I mentioned, along with some sea slugs that can actually take in those stinging cells and incorporate them for their own defensive use – what a strategy!!). Some animals are too large to be killed or paralyzed by ingesting the jellyfish’s toxin, but they’d be stung all the same and would likely avoid further contact, I expect. Somehow those gobies in the S. Atlantic have adapted to overcome that challenge, and thus I’m wondering if the little ones I saw may be doing the same. Perhaps not – they may have just been testing their own limits, of course! Either way, interesting behaviour, methinks.

  3. Old Jules says:

    Interesting story and a good pic. Something similar happened to me a couple of days ago [not having a camera when the event called]…… three ravens attacking a hawk circled about 100 feet above me. They were seriously attacking, darting in and pulling out feathers. The hawk was trying to catch updrafts to get away and all gradually gained altitude until they were too far away and too high to see. Looked as though the hawk was getting a little distance on them toward the end, but they might have killed him. I’ve watched a corvid or two play games with hawks in the past, but this is the first time I’ve ever seen them so determined to play for keeps.

    • Thanks for the comment and story, Jules, good to hear from you. I’ve seen ravens going after eagles quite a few times (though never for lengthy periods) – but have never seen them go after a hawk – interesting to hear, and quite the experience to witness, I bet!

  4. Paul thompson says:

    Very interesting Laurie. Great pic as usual.

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