I think, from a cursory look at a series of pictures, that most flatfish lie on their left side (that is, the “left” as compared to a typical fish). Are there any exceptions?
If so, is it because some species are left- or right-handed, or are there individuals within a single species that are left- and right-handed? If the former, what would cause such an evolutionary divergence?
If not, are there any reasons that an occasional opposite-handed mutant (I’m thinking of the occasional human being who has reversed internal organs) would not be successful within the flatfish population?
For most flatfishes, individual species or genera will go one way or the other, but it’s an amazing mix. Here’s a list of the families in Order Pleuronectiformes, the flatfish, with “sinistral” or “dextral” tagged to each to indicate whether “top” is what was originally left or right side.
Suborder Psettodidei
Family Psettodidae, two primitive species from Indonesia and Africa, go either way
Suborder Pleuronectoidea
Family Citharidae, go either way
Family Scophthalmidae, sinistral
Family Bothidae, “left-eyed” flounders, sinistral, and “California halibut,” a species that goes either way
Family Pleuronectidae, “right-eyed” flounders and halibuts, dextral
Suborder Soleoidei
Family Soleidae, the soles, dextral
Family Cynoglossidae, the tongue soles, sinistral
I have no info for flatfish, but I do for lobsters. They have one “pincher” claw and one “crusher” claw. These are definitely available on either side.
Thanks for the info; that’s pretty interesting. I was curious about flatfish particularly (as opposed to lobsters, for example) because it seems like a relatively severe modification is required for the fish to “flop” from one side to t’other, as opposed to the (seemingly) relatively simple pincher/crusher alteration. I was curious whether the genetics worked out to allow fish of both handednesses to interbreed (as it does, apparently).
Unless it’s a spiny lobster (panulirus interruptus). (Incidentally, I like spiny lobster better than lobsters with claws. I don’t know if it’s because of the species, or because they were fresher.)
I was watching a show about dolphins. There is a group of bottlenosed dolphins in, IIRC, the Carolinas that form up line-abreast to push fish to the shore of estuaries with their “bow waves”. Interestingly, they always land on their right sides. Over time, the teeth on the right side of their mouths will wear down because of the sand and mud they tak in whilst catching the fish.
I’ve never caught a flatfish; but I saw some dead ones on the shore of Terrel Creek, so it’s likely I’ll get some when I start fishing. I don’t recall which side of them was the top side.
Question: How does one clean a flatfish? When I was young and caught trout and catfish, I’d slit them up the belly. Are flatfish cleaned the same way? Or are they cleaned by cutting up the side?
