Ocean Watch
By Susan Scott
Clearing up miso
butterfish and black cod
In last Sunday's Star-Bulletin, I read a story about an aquaculture plan on the Big Island that said, "In a little over two years, a favorite island delicacy -- miso butterfish -- may be available from fresh, cold-water black cod."Since I grew up in the hinterlands, the sentence confused me. Is miso butterfish another name for black cod, or is it a dish made from black cod? And what's black cod?
First, about miso butterfish: It's a recipe. Miso is a paste made from soybeans and rice. This Japanese staple is common in Hawaii's and Japan's grocery stores.
Recipes for miso marinade vary but generally call for miso, sugar, ginger and rice wine stirred together. Some people marinate salmon, ahi and aku in this mixture, but the favorite is black cod, also known as butterfish.
It's possible to buy butterfish already miso-marinated, but at $10 to $11 a pound, it's more economical to prepare your own. This requires planning because the fish must soak one to two days, depending upon the recipe. After that, grill, bake or broil it.
As for black cod, it's not a cod. It's a sablefish (scientific name Anaplopoma fimbria) belonging not to the codfish family, but to another all its own.
Sablefish have black skin and get their name from the sable, a North Asian marten with black fur. Apparently the sablefish resembles a cod in shape, and that's where the name black cod comes from.
Sablefish live only in the cold waters of the Pacific Ocean ranging from California to Alaska, across the Bering Sea to Siberia and down the Kamchatka coast to Japan.
The biggest sablefish grow up to 40 inches long and weigh about 40 pounds, but the average catch is about 2 feet long and 10 pounds. Sablefish have exceptionally long lives. Some have been estimated to be 90 years old.
Japanese anglers once fished for sablefish in Alaskan and British Columbian waters. In the 1970s, however, the United States and Canada enacted 200-mile laws, banning all foreign fishing vessels within that distance of land.
The fish still get to Japan, though. The United States and Canada export most of their sablefish catch there, where people prize it for sushi.
People call sablefish butterfish because of its high oil content, but it's not a butterfish. The real butterfish is a bony little thing weighing just over a pound. This food fish (Peprilus triacanthus) grows fast and lives for only about three years. Butterfish range from Florida to Newfoundland, but most are caught in New England waters.
To defeat their many predators, butterfish often swim among swarms of jellyfish.
If you live in Britain, a butterfish is something else entirely. It's a 9-inch-long marine eel that lives along all British coasts. In the United States these eels are called rock eels or rock gunnels. The scientific name is Pholis gunnellus.
If you mention rock eels to a Brit, however, he'll think you mean dogfish, which in the United States are small sharks, but in Britain are ... Well, there's no end to it.
Even though these fish names are confusing, I think I've got it. When I see miso butterfish at my grocery store now, I'll know it's not a real butterfish, but a marinated black cod, which is really a sablefish.
And now that I know how to cook it, I'll even buy one.
Marine science writer Susan Scott can be reached at http://www.susanscott.net.
