Sea Discovery: Wolf eels, the not so terrifying “wolf-ish” fish

Hidden in the darkness of the deep, wolf eels are not as dangerous as they look according to The Marine Detective. Well, maybe not to their prey, but with divers, they tend to shy away in their caves and peek out. While their bulbous heads and large, toothy mouths can look frightening, these fish are generally slow-moving and sedentary. And yes, I said fish! Even though their common name suggests that they are an eel, wolf eels (Anarrhichthys ocellatus) are part of the wolffish family and not true eels.

A female wolf eel shows off her teeth. Photo: Dan Hershman

Wolf eels still have pectoral fins like most fishes, but the rest of their elongate body looks very eel-like. This body shape lets them slide into dark crevices and move stealthily along the seafloor. The body shape and movement of a wolf eel is similar to another eel-like fish we discussed a few weeks ago, gunnels.

A wolf eel swims into a hole in the rocks using its long body. Photo: Chris Wilson

The large teeth and jaws of the wolf eel may have you thinking they would be successful fish predators. This is true, but along with fish, wolf eels use their large teeth and massive jaws to prey on hard-shelled invertebrates like mussels, crabs and even spiny sea urchins. Wolf eels have teeth on the roof of their mouths to be able to crunch even the toughest of shells. This diverse diet helps sustain the wolf eel’s enormous (wolf-like) appetite.

Above is the upper jaw of a wolf eel with bony, tooth-like projections. Photo: Jackie Hildering

An unusual behaviour of these ancient-looking fish is that they mate for life! Monogamy isn’t common practice in the ocean, with plenty of fish in the sea and all, but wolf eels make it work. When wolf eels reach sexual maturity and find a mate, the two must find their perfect den to spend the rest of their life. Other wolf eels and octopuses are often looking for crevices and holes to have their dens, so there can be fierce competition and battles for the best spots (video).

A couple of wolf eels in their den. Photo: Dan Hershman

Wolf eels are not at risk in British Columbia, but they still face threats like pollution, which can negatively affect the health of their environment (like kelp forests) and decrease prey populations. They are also often accidentally caught by fishers. While these slower-moving, curious fish are always an exciting sight for divers, it is important to respect the animal’s space.

Check out below to see the amazing transition in colouring between juvenile and adult wolf eels in this Hakai Wild video.

Resources:

Wolf Eel – No Ugly Fish! by the Marine Detective (Article)

Wolf Eel: Lazy Lovers of the Pacific, Ocean Futures Society (Article)

Wolf Eel: eel that’s not an eel, Seattle Aquarium (Article)

Wolf Eel, Monterey Bay Aquarium (Article)


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