Let’s say you’re a bottom-dwelling fish that prefers to eat animals that often hide in the sea floor; things like crabs, shrimp, worms and mollusks.
To find your prey, your options could be:
– sit and wait for your hidden prey to move or rise on the sea floor and make itself more obvious.
– randomly swallow up mouthfuls of the muddy or sandy bottom and hope you got something edible. (Although often your result will just be a mouthful of sand. Yuck.)
– poke around in the bottom to see what you can find.
Option No. 3 seems pretty good, right? But, alas, what can a fish use to poke around in the sea floor?
Well, a number of species have adaptations that solve the problem. Catfish, cod, carp, sturgeon, nurse sharks and some other species have whisker-like organs near their mouth called barbels. (There’s a fish called a barbel that has … surprise! … barbels too.) Barbels have taste buds, allowing a fish to stick its barbels into the bottom to taste around for food without – and here’s the sweet part – having to get a mouthful of sand or mud.
(Let’s stop for a moment to imagine what life would be like if, say, our pinkie fingers had taste buds on them. Barbels are something like that.)
Another common bottom-dwelling fish has a different adaptation for finding food. The sea robin (Prionotus carolinus) has large pectoral (or side) fins that can open out like a fan. But the first three rays of the pectoral fin are separate from the rest of the fin. The sea robin can use these independently moving rays like feelers, to poke around in the sea floor and flush out prey. These feeler rays don’t have taste buds, so they’re not barbels.
Sea robins also use their rays sometimes to “walk” along the bottom.
Sea robins are common up and down the Atlantic coast, including here in Long Island Sound. Although they’re said to have a nice taste, most fishermen consider sea robins to be a nuisance fish, taking bait intended for more sought-after (and easier to filet) species.
Look for sea robins in The Maritime Aquarium’s “Sandy Bottom” exhibit and the “Ocean Beyond the Sound” exhibit (a.k.a. the big shark tank). There’s also a great image of a sea robin on the display graphic as you enter the aquarium galleries via the balcony over the harbor seals.