Tag Archives: Tomcod

What is a Cod?

Four species of fish in the Gulf of Alaska have the common name “cod,” but only two of these species, the tomcod and Pacific grey cod, are true cod. Common fish names are often misleading and confusing. For example, brown trout (Salmo trutta) belong to the genus Salmo, while cutthroat trout (Oncorhynchus clarki) and rainbow trout (Oncorhynchus mykiss) are in the genus Oncorhynchus. To confuse the issue even more, brook trout (Salvelinus fontinalis), lake trout (Salvelinus namaycush), and Dolly Varden trout (Salvelinus malma) are char, not trout. Also, in the southern United States, bullheads are catfish, while in Alaska, we call sculpins bullheads.

True Cod and Imposter Cod

Lingcod

Lingcod (Ophiodon elongatus) and black cod (Anoplopoma fimbria) are not only unrelatedto Pacific grey cod (Gadus macrocephalus) and Pacific tomcod (Microgadus proximus), but they look quite different from the two “true” cod species. Pollock (Gadus chalcogrammus), though, a species closely related to a Pacific grey cod, isn’t even referred to as a cod. With these confusing common names, we can forgive an angler for not knowing whether he has caught a “true cod” or some unrelated fish.

Pollock

Last week, I wrote about the crash of the Pacific cod population in the Gulf of Alaska. In that post, I was discussing only Pacific grey cod. Over the next few weeks, I’ll write posts about the true cod species as well as the cod imposters in Alaskan waters. I hope to clear up any confusion surrounding cod and their common names.

Pacific Tomcod

Tomcod

The Pacific tomcod (Microgadus proximus) is one of the smaller members of the cod family, reaching a maximum size of 12 inches (30.5 cm). Its body is slender and covered with small, thin scales, but it feels smooth to the touch. It ranges in color from olive green to brown on its dorsal surface and creamy white on its ventral surface. Like its cousin the grey cod, a tomcod has a barbel on its chin, three dorsal fins, two anal fins, a large head, and a large mouth with small teeth. A tomcod’s barbel is smaller than a Pacific grey cod’s barbel, and unlike a Pacific cod, a tomcod’s dorsal fins do not contain spines. Despite these differences, a tomcod looks very much like a small Pacific grey cod.

Tomcod range from central California to western Alaska and can be found anywhere from the surface to as deep as 700 feet. They feed on zooplankton, shrimp, worms, and small fish and in turn, are a food source for larger fish, seals, and sea lions. Because of their small size, tomcod are not an important species for either commercial or sport fishermen, but they are a good food fish and have a sweet, subtle flavor.

Next week, I’ll discuss grey cod. I have already posted about their declining numbers in Alaskan waters, but I’ll delve more into their biology, importance in the ecosystem, and their value as a human food source. The following week, I’ll point out the differences between Pacific and Atlantic cod.

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Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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