The official American Fisheries Society name is sablefish, but to nearly everyone who catches them, sells them, or eats them, the name is black cod. To add to the name confusion, this fish is in no way related to members of the actual cod family (Gadidae) which includes Pacific cod, walleye pollock, and hake.
Black cod are deep, deep water fish that favor the edge of the continental shelf along the north Pacific Rim. They are found on the North American side of the ocean form Cedros Island in Baja California, north to the Behring Sea. Black cod also dwell on them Asian side from Kamchatka south to Japan. Commercial concentrations of sablefish are generally encountered in depths between 200 and 500 fathoms (1200 to 3000 feet).
Though larger black cod seldom stray from the abyssal depths, the juveniles sometimes venture into near shore waters and school near the surface. In the August and September of 2014, we encountered seemingly endless numbers of 4 inch black cod nearly everywhere we fished for salmon. Based on what we found in the stomachs of the silvers landed, juvenile black cod were a substantial part of their diet during late season 2014.
Black cod spawn in January and February in the lower 48 and in March and April in Alaska. Their eggs are pelagic (drifting), smooth, and roughly 2 mm’s in diameter. One inch long juveniles have been found near the surface in May, an indication of hatching time and early growth rates. By age three the young black cod weigh close to three pounds. At five years of age they are about two feet long and the males are mature. The females mature at 6.5 years and over two feet in length. Maximum size for sablefish is about 60 pounds. The biggest sport caught one I’ve seen was 46 pounds,
Black cod have only one close relative, the skilfish. Also a deep water Pacific species, these fish grow to at least 200 pounds and possibly much larger. Unlike the sablefish, skilfish are quite rare. The Vancouver Aquarium one had a couple skilfish and some black cod in a tank. I’m not sure if they’re still there.
For any of you who think you’ve seen the photo of a very large black cod in the Pioneer Bar in Sitka – a 130 pounder – things aren’t what they seem. According to a biologist friend who has tipped a few in the P-bar, that’s a middling size skilfish in the photo, not a behemoth sablefish.
Black cod are among the most valuable commercially caught fish in Alaska with a strong Asian market. This can be owed to the high oil content. The domestic market for black cod is mostly high end restaurants on the west coast. Japanese buyers grade black cod in a rather odd way – by depth. Oil content is the big variable with sashimi grading and the price paid. Apparently, the depth at which these fish are caught and the oil content are directly correlated. The deeper the water the black cod comes from, the higher the oil content and the higher the sashimi grade.
Aside from humans, another mammalian predator, killer whales, also favor high oil content. Orcas will selectively pick sablefish from longline gear while ignoring other deep water species such as grenadiers and rockfish. More recently, sperm whales have begun picking the black cod off commercial gear, too. Given the excellent price paid for black cod, this predilection of the toothed whales doesn’t make them popular with longliners.
Black cod apparently migrate long distances. Some studies indicate migrations of over 2500 miles during the course of six or seven years. Sablefish feed on a wide variety of marine organisms including saury, lanternfish, crustaceans, worms, and a host of other small fish. In captivity they’ve been described as indiscriminate feeders, meaning they eat just about anything you throw in the tank. Black cod grow well in captivity, which, along with the strong market and high price, make them a likely candidate for aquaculture. A British Columbia company is now marketing organic, farm-raised black cod.
Commercial fishermen capture sablefish in deep water trawls and on longlines. The U.S. harvest in 2012 was 41 million pounds of which 31 million pounds came from Alaska and the rest was harvested in Washington, Oregon, and California. Prices range mostly from $4 to $7 per pound depending on the size of the fish. The sport harvest is relatively miniscule. We encounter black cod as an incidental catch when fishing halibut in “the deep, deep”. Hauling fish up from 600 feet or deeper is a muscular challenge – but the eating quality of black cod makes it worth the effort.
Rich in omega 3 and 6 oils, velvety in texture, with a thick white flake, black cod are both healthful and delicious. The oil content it difficult to over cook them and dry them out and the flavor is uniquely rich. In a reversal of fortunes, Chilean sea bass were initially marketed as a good substitute for depleted black cod. Both fish share similar qualities at the table. Successful management has brought black cod back to high and sustainable levels while a massive distant water industrial fleet has decimated the Chilean sea bass populations.