Wolffish: The Undead
It has chalky gray-blue skin, unblinking eyes, a mouthful of fangs and a habit of keeling over like a corpse in its cave.
Dracula? A werewolf? A zombie? Close. Meet the Atlantic wolffish.
“Actually, to me they look like the Creature from the Black Lagoon,” says senior aquarist Ernie Sawyer, who tends what might be the scariest-looking fish at Shedd Aquarium.
Look for the two Atlantic wolffish in the first left-hand habitat in the Oceans gallery. The dark, almost frosty environment replicates the North Atlantic offshore waters where wolffish lurk in seafloor caves 250 to 1,600 feet down. If their countenance makes your blood run cold, consider this: Natural antifreeze keeps their blood flowing in water temperatures that approach freezing.
They are as slow and ungainly as they look, swimming in undulating eel-like movements by wagging the tail from side to side. But mostly they sit. A wolffish will scoot out of its rocky lair to prey on bottom-dwelling shelled invertebrates, including sea stars, mussels, clams, sea urchins and lobsters. Its large, jowly mouth contains long front canines—hence the species’ common name—followed by clusters of five or six smaller fangs plus crushing molars on the roof of the mouth that together look like stalactites and stalagmites receding into a deep, dark cave.
Grabbing its prey whole, a wolffish chomps down hard, sending shell splinters flying. “Then,” Ernie says, “the fish sucks the food farther back into the mouth and—crunch, crunch—tenderizes it. A lot of juice and innards shoot out the gills. It’s quite a production.” So much so that he feeds the wolffish before the aquarium opens. Once a week, each fish gets shrimp with the shells on and a squid stuffed with large krill, smelt, silversides and clam for a balanced diet. Interestingly, the wolffish don’t bother the sea stars that share the habitat.
For all their ferocious looks, Ernie says that generally they are harmless to people, although “they have the dentition to do some damage if handled carelessly”— a hazard specific to fishermen and aquarists. But the wolffish have alarmed a few guests with an unusual behavior.
Wolffish go into what is called a period of slumber. And they do it a lot. While they’re napping, they look like they’ve gasped their last on the bottom of the habitat. Their lidless staring eyes and gaping mouth add to the lifeless effect. Ernie explains, “Wolffish only have pectoral fins—no pelvic fins—and their bodies are laterally flattened and somewhat top heavy. When they are resting, they just start to list, and over they go.”
The aquarium even posted a sign to that effect—“Shhh…the wolffish is sleeping!”—at the exhibit. But the wolffish don’t take catnaps; the period of slumber can last half an hour or longer, scaring concerned guests.
The truly frightening thing about Atlantic wolffish, however, is that their U.S.-Canadian population has plummeted by 97 percent in the last 30 years. While wolffish are not targeted by a commercial fishery on this side of the Atlantic, huge numbers of the large fish still wind up as bycatch drowned in trawl nets. And the heavy, weighted bottom-trawl nets also destroy their seafloor habitat. Efforts to have them protected under the U.S. Endangered Species Act have been unsuccessful.
So while Shedd’s cadaverous Atlantic wolffish are alive and well, for all appearances the species may soon be only a ghostly memory in North American waters.