Naturespeak A naturalist's view of the world

November 28, 2009

Not All Bad

Filed under: Uncategorized — wykes @ 9:33 pm

If there’s one thing to say about gobies it’s that they are not evil. Yes, as an alien species here in the New World their existence threatens the delicate balance of life in the Lakes. Go ahead and Google the word Round Goby and you’ll be bombarded by page after page detailing the dastardly deeds of this finny villain. All of the bad press is certainly true – they eat fish eggs, out-compete native fish, and they are ugly (although this last charge is certainly not the most heinous). These destructive little Europeans are home-wreckers here in the Great Lakes. But, it is worth while to consider that back in their home world they are just another fish in their sea. They are, in fact, quite incredible little fish. This alone is enough reason to take a look at one of these fellows through un-judgmental eyes every once and a while.

The Round Goby is just another fish in the Caspian Sea- one of the largest bodies of enclosed water in the world.  It’s hard to say exactly – or easily – exactly where the Caspian lies because it is surrounded by so many countries. Let’s see, there’s Kazakhstan, Russia, Turkmenistan, Iran and a few more “stans.”  Back in the bad old days you could have simply said that they are from Russia (with love), but not any more. Gobies are also found in the Black Sea which happens to be bordered by the likes of  Turkey, Bulgaria, Romainia, Ukraine, etc., etc.  It is very possible that the gobies came to Lake Erie  in order to see what it was like to be in a place bordered by only two countries!  Admittedly, this is only a theory. This was a fish with no country to call it’s own. At any rate, there are at least five related goby species found in that region and all are stocky, tubular, and bottom dwelling (and all equally without a home country). Our little alien friend happens to be a very typical Goby.

I plucked our sample Goby (see above) out of the Lake Erie sand last month. This creature was waiting out a wind tide within the confines of a little pool of water under a rock (see below). He was very much alive when handled for these shots. The first thing to notice about this species is the compact structure and the bulldog facial features. The blue-gray eyes are located high up on the head and the mouth appears a bit over-sized. Gobies will eat anything that fits into that sizable maw – be it a bait worm or another fish of slightly smaller size. They are almost cartoonish is appearance (although not so funny if you are a bait worm or that other slightly smaller fish!).

Although you can’t see it in these views, the top fin has a prominent black dot on it which is employed as a signal beackon for “talking with” other gobies by semaphore. There are also two huge side fins, called pectorals, that flare out from just behind the head. The most unique fin feature is the pelvic, or bottom, fin that you can clearly see in the view below. This single fin is actually a pair of fins that are fused together to form a suction cup. None of our native fish have this bottom-hugging  feature.

Gobies have to stick to the bottom because they have no swim bladders to keep them afloat. They scurry along the substrate using their huge pectoral fins like legs. Whenever they achieve some height in the water column, after great exertion, they sink back to the bottom as soon as the effort ceases. I suppose I should mention that this individual appears to be so dark because it was a male in breeding color. Normally these fish are light brown with dark side spots, but males can turn dark brown or even black when in “the mood.” Even their eyes will cloud over with an iridescent glaze.

Apart from being interesting to look at, Round Gobies do reveal an unintentional good side to their alien nature. Here in their Great Lakes home they have proven to be a Godsend for Lake Erie Water Snakes, who eat them like popcorn. Small and large-mouth bass, along with Walleye, will also feast upon them. One fishing tackle manufacturer has even come out with a Goby-shaped lure as means to catch lunker fish.

So, as you can see, they’re not all bad.

3 Comments »

  1. Voracious eaters, yes, and certainly a pest in their non-native Great Lakes waters. I don’t think they’re ugly, though – they have a certain buggy-eyed comic appeal. Or perhaps they’re so ugly they’re cute?

    Comment by Holly — December 1, 2009 @ 2:13 pm

  2. Holly:
    You know, I agree with you. Ugliness is relative. To them, we are probably one of the most ridiculous looking creatures on earth!

    Comment by Gerry Wykes — December 1, 2009 @ 8:40 pm

  3. In a world where invasives are now the norm, and the havoc they wreak is considered by many just another day at the beach, it’s kind of nice to see that some invasives have some redeeming qualities, even if they are small.

    Fish have never been my forte, but I have some fishy friends who write about fish in ways that make them very interesting and have piqued my interest. This post is right up there among them. Thanks!

    Comment by Ellen — December 2, 2009 @ 11:52 am

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