What better way to begin a book about Pacific Coast seafood than with salmon? In addition to it being one of the most delicious foods our part of the Pacific has to offer, no other fish is a better symbol of the natural resources of the region, and of its human history and traditions. And no other fish more clearly ties together the land, the rivers, and the sea, the impact of man's activities on this interrelated environment, and the challenges facing us and the fish in the present and future. As much as salmon and its freshwater cousins rainbow trout and arctic char symbolize all that is wild about the Pacific Northwest, they are also symbolic of the revolution in the fish market brought about by aquaculture. In the last quarter of the twentieth century, salmon farming has forever altered the world of salmon, virtually erasing the notion of fresh salmon as a seasonal food. The following pages will help you to sort out the various species and forms of salmon and to use each to its best advantage. Pacific Salmon
King or chinook, Oncorhynchus tshawytscha
Coho or silver, O. kisutch
Sockeye or red, O. nerka
Chum or "silverbright," O. keta
Pink, O. gorbuscha
Steelhead (rainbow trout), O. mykiss
On any day of the year, most any supermarket or fish market in the West is likely to be offering some sort of salmon. The selection can include anything from whole fish at under a dollar per pound to fillets and steaks at ten dollars or more. The fish may be any of six or seven different species, caught in the wild or raised on a fish farm, all varying considerably in size, flavor, fat content, range, and season. Most of this chapter will be devoted to the differences among the various salmons, and how to use each to its best advantage. But first, a look at the basic life cycle of all salmons, which is useful in understanding those differences. Salmon, along with many trouts, are anadromous fish, which means their life cycle includes phases in both fresh and salt water. Because both salmon and trout are so valued by both commercial and sport fishermen, and because much of their life takes place in full view of man in rivers and creeks rather than in some unknown region of the ocean, the Salmonidae are one of the most studied families of fish, and salmon observers have developed a rich and specialized vocabulary for their developmental stages.
Salmon begin their lives as eggs laid on the gravelly bed of a river or creek. After hatching, which may not take place for several months, the immature fish spend anywhere from a few weeks to two years in fresh water, depending on the species. During this period, they grow and develop through various stages, from the newly hatched fry called "alevins," to the immature "parr" with their camouflage markings, and finally to the "smolt" that are preparing for the conversion to salt water as they migrate to the ocean. After one to four years in the ocean, feeding and constantly growing, salmon reach sexual maturity and return from the ocean to the river of their birth to spawn and complete the cycle. In one of the miracles of instinctive behavior, fish that have spent years in the open ocean find their way across hundreds of miles, back to the same stretch of gravel in the same branch of the river where they hatched, to lay the eggs that will be the next generation. How they do it is still a mystery, but it may involve a neurological "inner compass" attuned to the earth's magnetic field, changes in day length that define the seasons, and a sense of smell that can detect incredibly subtle differences in the water from one creek fork to another. Unlike Atlantic salmon and some other salmonids, which can spawn several times and return to the ocean afterwards, Pacific salmon make a single spawning return in their lifetime, and undergo irreversible physical changes in the process. They also stop feeding once they enter fresh water, relying on accumulated body fat for the energy needed to swim upstream, sometimes hundreds of miles. If she has managed to escape predation by whales, sea lions, and brown bears, not to mention fishing humans, a female salmon locates a suitable spot on the stream bed, makes a hollow in the gravel, and lays hundreds of eggs. Nearby male salmon add sperm (milt) to fertilize the eggs. After spawning, all the adults die. Those that are not eaten by gulls or bald eagles decompose in the stream, providing nutrients to the food chain that will ultimately nourish their own offspring. Because salmon spawning is so site-specific, the stocks in one river rarely if ever cross-breed with those of another river. Even within the same stream, different stocks have evolved that enter the river and spawn at different times of year. Thus each salmon "run," a particular combination of species, river, and season, represents a genetically distinct population, adapted to the precise conditions of its spawning grounds and ocean range.
With this specialization comes vulnerability. If a particular spawning run is interfered with, it can become threatened with drastic decline or even extinction. And Pacific salmon have faced plenty of threats. Dams on many rivers block access to upstream waters. Erosion of watersheds from logging, grazing, or other activity can cover spawning gravel with silt, smothering eggs and reducing the attractiveness to future spawners. Water diversions can result in water that is too shallow, too slow-moving, or too warm for salmon that have evolved to match conditions unchanged for millennia. Unscreened irrigation pumps can pull in juvenile salmon by the thousands, a major problem in California's Sacramento Valley. In the case of chinook salmon, which spawn at three to four years of age, one year of spawning failure can make a serious dent in the population, but there are still younger fish out in the ocean that may do better next year. However, if the spawning grounds are unreachable or unusable four or five years in a row, that's it. One of the first major irrigation projects in California's Central Valley, the Friant Dam completed in 1942, cut off the spring run of chinooks on the San Joaquin River from its only spawning grounds, and within a few years the run was extinct. The story has been repeated on other Western rivers, especially in the Columbia River system, in which more than 200 historic salmon stocks have become extinct and at least 75 more are threatened or endangered. In fact, only a handful of wild salmon runs from California to British Columbia can be called healthy.
The exception to all this gloom is Alaska, which has continued to produce large harvests of all five Pacific salmon species year after year. The Alaska salmon fisheries are characterized by a relatively pristine environment and effective management, augmented by aggressive hatchery production. With abundant fresh water flow in largely undammed rivers, and little of the environmental degradation that has depressed or destroyed so many salmon runs in the Lower 48, Alaska's wild-spawning salmon stocks are in good shape for the present. Fishery managers have also figured out how to allow large catches while ensuring sufficient spawning return to the rivers, so the wild stocks are maintaining their numbers from year to year. Add to that the many millions of juvenile salmon released each year by the state's salmon hatcheries, some of which survive to return to the river of their birth two to four years later. It's the truest form of "ocean ranching," a little like turning cattle loose on the open range, except you don't need to herd them in; the salmon return on their own, driven by the same spawning impulses as their wild-born cousins. Together, Alaska's wild-spawned and hatchery salmon make up fully 90 percent of all the wild-caught salmon taken in U.S. waters. As long as current management and hatchery policies remain the same, this is one fishery that should be sustainable at the high levels that have characterized the last decade. If anything, Alaska's salmon fishermen sometimes face problems from too many fish. Processors have tried various forms to deal with the excess supply, some of which are succeeding in the marketplace (salmon burgers) while others (salmon ham, breaded portions) have struggled.
A Note on Names
In addition to common names, many species of fish and shellfish in this book are identified by their Latin or "scientific" names. To avoid confusion among common names in many languages, as well as multiple common names within a single language, the 18th-century Swedish botanist Linnaeus established a Latin-based system of classification of living things which is still in use today. This system assigns a unique, two-part, Latinized name to each species while identifying groups of closely related species. For example, chinook (king) salmon is known scientifically as Oncorhynchus tshawytscha. The first part of the name, always capitalized, identifies the genus, a group of species having certain traits in common. Oncorhynchus (Greek for "hooked nose," a reference to the distorted jaws of spawning salmon) covers all varieties of Pacific salmon as well as several trouts native to the Pacific Rim. The second part of the name, the species, is not capitalized, and applies uniquely to chinook salmon. Sockeye salmon is Oncorhynchus nerka, coho salmon is O. kisutch, and so on (where the genus is clear from context, it is sometimes reduced to an initial). Species names sometimes refer to a discoverer (pallasi), or a geographic location (californicus), or some anatomical feature (melanops, "black-eyed"). In the case of Pacific salmon, they come from native Alaskan and Siberian names for the fish. Several genera (plural of genus) may be grouped together into families, the names of which end in -idae (such as Salmonidae, salmons and trouts, or Pleuronectidae, right-eyed flounders). Families in turn belong to orders such as Salmoniformes (the Salmonidae plus the Osmeridae, smelts) or Gadiformes (cods and their relatives). These terms occasionally show up in the form of adjectives such as "salmonid" and "gadiform."
Shopping for Salmon
Salmon is available in steaks, fillets, whole and half fish, and sections or "roasts" of various sizes. Fillets of a given type usually sell for slightly more than steaks, because the latter includes bones and belly flaps that are removed in filleting. If you can use the quantity, buying a whole or half salmon will save you some money (if the price is less than two-thirds the price of fillets, it's a better deal). There's not much more impressive than a whole roasted, poached, or grilled salmon for feeding a crowd. Even if you plan to cook it in pieces, cutting your own salmon allows you to create portions of just the size and shape you want, something you can't always count on finding at the fish market. As a bonus, you have the head and bones for chowder or other uses.
Knowing your salmon species can help you get the best bargain, and cook your salmon to the best advantage. Here is a rundown of the various salmons that can be found in our markets, in terms of size, color, texture, and the fat content that is one of the main variables in flavor.
Chinook Is King
King, or chinook, is the least numerous of the Pacific salmons, but the most valuable. From California to Alaska, this is the species that produces the largest salmon (fish of 20 pounds or more are common in some areas), and for my money the best flavor. Kings generally spawn in larger rivers, often hundreds of miles inland, which requires large reserves of fat. The fat content of a given king salmon will depend on the location, time of year, and food supply, but in general kings are among the fattest wild salmon. This makes them ideal for grilling, broiling, and other dry-heat cooking methods, although they are also delicious poached, steamed, or baked.
King salmon are fished commercially from central California to northwest Alaska, and are virtually the only salmon caught commercially south of British Columbia. (Chinook is the official name in field guides and regulations, but just about everyone in the trade calls them kings.) Perhaps it's partly local loyalty, or just the fact that these were the first salmon I learned to cook, but for me a midsummer king salmon caught off Bodega Bay, San Francisco, Half Moon Bay, or Monterey will always be the definition of salmon flavor. Thanks in part to aggressive publicity, the large, rich kings from Alaska's Copper River, available fresh in late May and June, command the highest prices in the market; some aficionados prefer the even fatter kings from the Yukon.
Coho = Silver
Silver, or coho, salmon comes close to king in size and flavor, and can be used interchangeably with king in recipes. Once fairly common all up and down the coast, coho mainly spawn in shorter coastal rivers and have suffered more loss of critical spawning habitat than any other species. Coastal stocks in Oregon and California are officially "threatened" under the Endangered Species Act, and both sport and commercial fishermen must release any silvers they catch. Some relatively healthy runs of coho remain in Alaska, especially in the southeastern region, and there is some commercial fishing for cohos in Canada as well. Peak coho catches are in July and August; look for fresh coho specials in late summer, or frozen fillet portions other times of year.
Seldom Seen Though one of the smaller varieties of Pacific salmon, sockeye is among the most important commercially. In some years it is the most numerous salmon species caught in Alaska, and it brings in by far the most dollar value. Yet this fish can be hard to find in local markets in any form other than canned. Sockeye, or red, salmon are found as far south as California, but mostly range from the Columbia northward. Where they occur, they can occur in huge numbers. In Bristol Bay in southwest Alaska, home to the world's largest sockeye runs, as many as 60 million of these fish return to their spawning streams each summer, and fishermen harvest tens of millions of fish year after year. (One hopes that two successive bad seasons in Bristol Bay in 1997 and 1998 had to do with weather cycles, and are not signs of a long-term decline.) Another major sockeye fishery occurs at the mouth of the Copper River, where the reds outnumber the famous kings twenty to one. These large, apparently sustainable catches of sockeye are even more remarkable in that, unlike some other Alaska salmon fisheries, the fish are all from natural spawning populations, not augmented by hatcheries. For years, the best Alaska sockeye salmon went frozen to Japan, and the rest into cans or smokehouses. (Sockeye is the premium canned salmon variety, commanding twice the price of pink salmon.) In the late 1990s, however, Japanese enthusiasm for Alaska reds waned for a variety of reasons, including a sagging economy in Japan, the growing world supply of cheap farmed salmon, and lingering resentment over a lawsuit brought by a group of Bristol Bay fishermen against the key buyers. If this pattern continues, sockeye processors may look to the domestic market to sell more of their fish both fresh and frozen, which would be fine with me. Sockeye rarely top 6 pounds, but they pack a lot of flavor. Where bigger salmon often feed on small fish like anchovies and herring, the sockeye diet runs to zooplankton, including larvae of crabs and other shellfish as well as the tiny shrimplike krill. The result is a distinctive, especially "wild" flavor, as well as an especially strong meat color--like other salmon but more so. Although the common name "red salmon" refers to the bright skin color of spawning fish, it also reflects the deep red-orange of the meat. Those unaccustomed to sockeye sometimes think the color looks odd or fake.
Chum and Pink: Bargain-Basement Salmon
For those with the money to spend, it's hard to beat king, coho, or sockeye salmon. But two other species, chum and pink, also offer good eating, at a lower price. Both are plentiful, particularly in Alaska, and both are common in supermarkets as a less expensive alternative to the glamour salmons. In fact, they can be downright cheap, with whole fish sometimes selling for around a dollar a pound. As long as you remember not to expect the same flavor and fat content as in the other types, these cheaper salmon can be among the best buys in the fish market. Chum salmon makes up 15 to 20 percent of the total Alaska salmon tonnage most years, versus about 10 percent for king and coho combined. Similar in size to coho, but considerably leaner, chum is perhaps the most variable salmon in the quality of the fish that come to market. At its best it can be a delicious, attractive fish; at its worst, it is disappointingly pale and bland. Although chum salmon is the official name for this species, you would hardly know it from advertisements or package labels. A few products use the name "keta," but almost all of the fresh and frozen chum sold outside Alaska goes under the attractive-sounding label "silverbright," sometimes spelled "silverbrite." Although it sounds more like a brand name for toothpaste or metal polish, and certainly invites confusion with "silver" (coho) salmon, "silverbright" actually has a specific meaning within the fish trade. When caught out in the ocean, when they are still feeding actively and their fat content and flavor are highest, chum salmon are as silvery in color as real silver salmon, though they lack the identifying black spots of the latter. Fish in this condition, known as "silverbright," offer the best eating and command the highest prices. However, most chums are caught not in the open ocean, but in river mouths and estuaries as they concentrate before spawning. Like other salmons, once a chum heads into fresh water it stops feeding and lives on its stored fat. In a matter of days, the meat becomes noticeably paler and lower in fat, with a corresponding loss of flavor and eye appeal. Hormonal changes cause the skin color to get progressively darker and marked with vertical bars and irregular splotches of red and green. Fishermen and processors rely largely on these color changes, described in a range of terms like bright, semi-bright, and dark, to decide on the market value of a give! n batch of fish. Unfortunately, the distinctions in skin color are not always followed at the retail market, where chums of any shade are likely to be labeled "silverbright." I have yet to see a chum salmon in a supermarket that matches the color of a true silverbright. Still, I have had plenty of very good meals from these fish. Just choose the ones with the brightest skin and the reddest meat. Smaller, more plentiful, and even cheaper than chum is pink salmon, typically sold as a frozen headed and gutted fish of 2 to 3 pounds. Pinks are by far the most numerous salmon species in Alaska, with annual landings as high as 100 million fish, outnumbering all other species combined. Even with their smaller size, this amounts to 35 to 40 percent of the state's total tonnage of salmon. Pink salmon is the least typical of the Pacific salmons; it's relatively lean, with a finer flake and milder flavor than the other varieties. In fact, the best way to approach this species may be to forget that it is a salmon, and treat it as a salmon-colored alternative to various white-fleshed fish. A whole thawed pink salmon is one of the easiest of fish to fillet, and yields almost 75 percent of its weight in edible meat. The fillets can fill in nicely in any recipe calling for lean, moderately flavored fish with a fine texture, such as rainbow trout, weakfish, redfish, or corbina. Sauteing, steaming, and baking are among the best cooking methods. The fillets take on seasonings readily; a liberal sprinkling of a packaged Chesapeake or Louisiana-style spice mix is an easy way to jazz up their flavor. A whole pink salmon or half of a chum is also a good candidate for baking or roasting. Both chum and pink salmon carry most of their fat just under the skin, rather than throughout the meat as the other salmons do; cooking them with the skin on, so the fat bastes the meat as it cooks, maximizes both flavor and moisture. Leftovers are useful in salads, salmon cakes, stuffings for mushrooms, or any other way you might use canned salmon. To select a frozen pink, look for one that has most of its scales intact; a lot of missing scales, especially in vertical marks that come from a net, are signs that the fish may be bruised. The fish should be rock-hard, with no ice crystals in the bag that would indicate thawing and refreezing. Allow at least 24 hours for the fish to thaw in the refrigerator (set it in a pan to catch the inevitable drippings). Rinse the inside of the fish well before cooking, and remove any traces of blood along the backbone.
Steelhead Is Salmon, Too
Rainbow trout, which has recently been reclassified to the same genus as the Pacific salmons, is mainly a freshwater fish, but a certain percentage of the fish migrate to the ocean one or more times in their lifetime. There, they adopt the diet and habits of salmon, in the process losing their rainbow colors and taking on a salmonlike color in both the skin and the meat. On their return to the river of their birth, these fish are known as steelhead, a favorite quarry of sport anglers. Although they are strictly game fish in most of their range, and limited to catch-and-release fishing in some areas to preserve threatened stocks, there is a small commercial take of steelhead as part of the in-river salmon fisheries on the Columbia, and also on some Indian reservations. It's a controversial fishery, and some restaurants and retailers in Washington and Oregon refuse to buy these fish out of sympathy with (or fear of boycott from) sport fishermen. I haven't heard of this happening! in California, which may be why some of the Columbia catch winds up here. In any case, it's a fine-tasting fish, a bit paler and milder than salmon. Wild steelhead is rare in the market. Most of what is sold as "steelhead" is rainbow trout raised on farms, either in salt water (see below) or fresh.
Not too many years ago, if you saw fresh salmon in a West Coast fish market, you could assume it was caught somewhere along the Pacific Coast. Today, it's just as likely to have come from a fish farm, possibly one halfway around the world. The salmon farming that has revolutionized the world salmon market originated in Norway, with the species native to the north Atlantic (Salmo salar). Seeing the catch of wild salmon in decline, due to the familiar combination of overfishing and habitat alteration, the Norwegian salmon industry changed its focus in the 1970s from catching salmon to raising them in captivity. From a few Norwegian fjords, the technology of saltwater salmon farming has spread around the world to various coldwater sites in northern Europe as well as Washington, Maine, both coasts of Canada, New Zealand, and Chile. The typical salmon farm consists of an array of circular or rectangular floating net pens, accessible by boats or piers, in a sheltered saltwater site such as a fjord or deep bay. The pens are stocked with 6-inch juvenile salmon called smolts, usually spawned in the farm's own freshwater hatchery from its own broodstock. Several times a day, either manually or through automated systems, the farmer scatters pellets of feed based mainly on fish meal over the surface of the pen, and they are gobbled by the salmon as they slowly sink. In 14 to 18 monthsthe time keeps getting shorter as farmers breed for faster growth and feed producers refine their formulasthe fish grow to market size (4 to 10 pounds). As salmon farming has grown more efficient, the fish have become less expensive. When farmed salmon first hit the market twenty years ago, they were mainly an off-season replacement for wild salmon, sold to those who would pay the price for a fresh salmon during the winter. Once the wild Pacific salmon season opened in the spring, the farmed fish could not compete in price. By the late eighties, however, the cost of farmed salmon had dropped to the level of the wild fish, and farmed salmon gradually became a year-round alternative. Over the last decade, as supply has continued to grow and production costs have continued to fall, farmed salmon has actually depressed the price of wild, and fishermen routinely settle for prices lower than those that would have sent them out on strike in past years. Atlantic salmon remains the most popular species with saltwater farmers, although various Pacific species can be raised by the same methods. Coho salmon was an early favorite with Northwestern farmers, and remains so in Chile, but these days it is mainly a niche item for some freshwater farmers. King salmon performs nearly as well as Atlantic in British Columbia, and a stalwart group of B.C. farmers has stuck with this native variety while others have switched to the slightly more profitable Atlantics. In Washington farms, as in Maine and eastern Canada, Atlantics are the rule. Maybe it's just my regional palate, but given the choice between a farmed Atlantic and a farmed king, I'll take the latter. The one Pacific species that has succeeded worldwide in salmon farms is rainbow trout, which has come on very strong over the last decade in nearly every growing region. Rainbows have been aquacultured far longer than any other salmonid, though mainly as small fish in fresh water; but it turns out they will also grow to salmon size (up to 8 pounds) in net pens, in either fresh or salt water, and if fed like salmon their meat looks and tastes a lot like salmon. Chile in particular is producing a lot of saltwater rainbows, which are variously sold as salmon trout, sea trout, or steelhead, although their rainbow-striped skin makes them easy to tell apart from wild steelhead. All the farmed salmons share some basic advantages and disadvantages. If nothing else, being available every week of the year in fresh form would give them an advantage, but many chefs and retailers choose them even when wild fish are available because of their consistent quality, size, and shape. And as already noted, the price has gotten more and more attractive. Flavor is a bit more subjective; some tasters find the flavor of farmed fish inferior to wild, while others prefer it. The biggest disadvantage (and this goes for salmon, steelhead, and arctic char alike) is that with the "high-energy" feed formulas that yield rapid growth, these fish deposit a lot of excess calories in the form of fat. Now, some fat is a good thing; just as in beef, fat means flavor in salmon, and a lot of the most prized wild salmon, like Alaska's Copper River and Yukon River kings, are favored precisely because they are fatter than others, in preparation for longer upstream migration. And I know it's "good fat" of the omega-3 variety. But one can have too much of a good thing, and for my money most farmed salmon simply tastes and feels too fatty (especially the belly meat, which can cook up downright greasy). Perhaps if enough of us who feel this way speak up about it, the word will get back to the farmers and feed manufacturers and they can find a way to "finish" the fish with a little less fat. On the other hand, all that fat means it's a lot harder to overcook farmed salmon. Even when cooked to the fully opaque stage, farmed salmon remains juicy throughout, giving it a much wider margin of error than many leaner fish. Still, in a recipe where the drippings from the fish are retained in the dish, I much prefer wild salmon to farmed.
How to Grow a Salmon-Colored Salmon
One of the distinguishing traits of all salmons is orange-red meat. But this color is not inherent in the fish; it comes from its diet. Most crustaceans contain a natural pigment called astaxanthin (which is, incidentally, the reason the shells of crab, lobster, and shrimp turn bright red when cooked). In the ocean phase of their life, wild salmon eat large quantities of small shrimp and their smaller relatives called krill, and in the process accumulate the astaxanthin in their flesh. Captive salmon can survive quite nicely on a diet of fish meal, so long as it has an appropriate mixture of protein and fat. But without a source of dietary astaxanthin (or other carotenoid pigments) the meat will never develop that appealing "salmon" color; it will have the ivory color of farmed trout, or of that small minority of wild salmon that are genetically unable to deposit the pigment in their meat. Conversely, trout fed a diet containing xanthins will develop a salmon color, even in fresh water. So, to grow a salmon that looks like salmon, farmers need feed with some form of pigment added. One source of pigment for feed manufacturers is shrimp or crawfish meal, but these are relatively expensive. Another option is canthaxanthin, a related pigment found in many plants, including carrots and marigolds, and widely used in food products from catsup to poultry feed. Both astaxanthin and canthaxanthin can be synthesized in the laboratory, producing molecules chemically identical to the natural form but at a lower cost. Synthetic astaxanthin, although the more expensive of the two, is also the more effective, and by the early 1990s it had become the standard pigment used by most salmon farmers around the world. The United States Food and Drug Administration did not approve the use of synthetic astaxanthin in fish feed until 1995, but when it did, many farmers and feed producers quickly converted from canthaxanthin to astaxanthin. Shellfish are not the only natural source of astaxanthin; among the other organisms that produce this pigment is a yeast, Phaffia rhodozyma, which can be grown commercially on a large scale. Phaffia may turn out to be a more economical source of pigment than the synthetic form, with a possible marketing advantage in claiming a more "natural" product.
Rainbow Trout Oncorhynchus mykiss (formerly Salmo gairdneri)
Through all the booms and busts and next-big-things of the aquaculture industry, one species has remained in steady supply: rainbow trout. A daily staple of the fresh fish market, these fish range in size from single-serving fish of around half a pound to 3-pounders perfect for the poaching pan. Processors now supply this fish in various forms (whole, fillets, boned, preseasoned), and even in different colors. Native to western North America, rainbow trout is among the world's most widely transplanted fish species. Wild populations have been established (mainly for sport fishing purposes) in most of the temperate parts of the world, across North America and northern Eurasia as well as New Zealand, Tasmania, South America, and South Africa. It's proven just as adaptable as a farmed fish; in fact, most of the world's production comes not from the United States but from northern Europe. Trout or Salmon? Originally found in the rivers of North America west of the Continental Divide, rainbow trout is usually identified in older books by the Latin name Salmo gairdneri, part of the same genus as Atlantic salmon and various Eastern and European trouts. However, the name has been a subject of debate for more than a century, with many scientists arguing that rainbow trout (especially in its seagoing form, steelhead) has important anatomical and behavioral traits more in common with the Pacific salmons (genus Oncorhynchus) than with other Salmo species. Others observed that rainbow trout was nearly identical to the Kamchatka trout of northeast Asia, identified in 1792 by Johann Walbaum as S. mykiss. Genetic mapping studies in the 1970s and '80s confirmed both these arguments, and in 1988 ichthyologists Gerald R. Smith and Ralph F. Stearley proposed to reclassify rainbow and Kamchatka trout as a single species of Oncorhynchus; retaining Walbaum's prior species name yielded O. mykiss. ! The American Fisheries Society adopted this usage in 1989. U.S. trout production has remained fairly constant in recent years at around 25,000 metric tons per year--nearly 60 million fish. Approximately 80 percent of that comes from one state, Idaho. Most of Idaho's farms are located near the Snake River, where there is an abundant supply of clean, cool water. An extensive aquifer gathers runoff from snowmelt in the northern Rockies and the Snake River Plateau, transporting it through the porous volcanic rock and releasing it in springs that feed into the river. Some of this water is impounded in ponds and raceways (flow-through channels) where the trout are raised from hatchery fingerlings to market size. While raceway trout rarely top 2 to 3 pounds, a few farmers on larger freshwater lakes are growing trout to larger sizes, up to 8 pounds, in floating net pens like those used in saltwater salmon farms. One of the largest of these farms is in eastern Washington, in one of the series of long, narrow lakes behind dams that make up the middle reaches of the Columbia River. Their fish, which has rainbow skin but is otherwise more similar in appearance, flavor, and fat content to farmed salmon than to other trout, can be used interchangeably with salmon. In the wild or on the farm, in fresh water or salt, the color of a trout's flesh depends on its food supply. The vast majority of farmed rainbow trout get a diet based on fish meal, and they have pale-colored meat that cooks up to an ivory color, similar to that of a wild trout in a freshwater stream. However, feeding the same trout a salmon diet containing xanthin pigments will give the meat a reddish-orange color like that of its seagoing cousins, and, to my taste, a somewhat fuller flavor. Many freshwater trout farmers have added red-meated rainbows to their product line. The most colorful trout of all, and also the least common, are "golden" rainbow trout. Originally developed in West Virginia as a sport fish, these strikingly colored fish represent not a separate species, but a particular color strain of the familiar domesticated O. mykiss. (Despite what some fishmongers might claim, golden rainbows have nothing to do with the wild golden trout of California [O. aguabonita], a separate species native to a few streams in the southern Sierra Nevada.) By crossing and back-crossing descendants of a single golden-colored mutant rainbow spawned in 1954, breeders were able to create a true-breeding stock of trout with a brilliant golden-yellow skin, marked with the characteristic lengthwise rainbow stripes of normally pigmented rainbow trout. Farmed golden rainbows, usually with red flesh, are sometimes found alongside other farmed rainbows in fish markets and supermarkets. Besides being pretty to look at, they are comparable in taste to other red-m! eated trout, meaning slightly fuller in flavor than ordinary rainbows. All the small farmed trouts have moderately rich flesh, with a fat content of around 7 percent. Whole fish are ideal for pan-frying or grilling if small, and poaching, roasting, or baking if larger. Uniformly sized 6- to 8-ounce fish are favored by the restaurant trade, and generally command a premium price over the more randomly sized fish in the retail market. A fish of 1 to 1-1/2 pounds is a convenient size to serve two, a 2- to 3-pounder to serve four. Some small trout are sold as head-on boneless fish, ideal for stuffing or for cooking butterfly style (with both fillets attached by the skin, generally with the head removed). Larger trout are sometimes sold in fillet form, with some processors removing the pin bones for a completely boneless fillet. I always cook trout with the skin on; it helps hold the meat together, as well as providing flavor (most of which is in the thin fat layer just under the skin). I also like to eat the skin, but some prefer to leave it behind on! the plate. If you can't find trout fillets in your market, you can always buy a whole trout and have it cut into fillets at the fish counter, or do it yourself. If you want your fillets to be completely boneless, run your fingertips down the middle of the fillet from the head end to locate the strip of tiny pin bones; they continue about halfway to the tail end. With a fillet knife or a thin boning knife, cut as close as possible along one side of the pin bones, cutting down to but not through the skin. Repeat on the other side of the pin bones, then cut under the bones to remove them. This leaves a narrow channel in the meat that mostly disappears in cooking as the skin shrinks. You might also find live rainbow trout of anywhere from a pound on up in markets with freshwater tanks. For now that means mostly Asian markets, although more full-service Western fish markets are adding live seafood tanks. The classic use for live trout is in truite au bleu, but it's also a good way to ensure the freshest possible fish for any recipe.
Arctic Char Salvelinus alpinus
The newest member of the salmonid family to enter the aquaculture mainstream is arctic char. Part of a branch of the Salmonidae that includes brook trout, lake trout, and Dolly Varden, arctic char is native to the far northern reaches of North America and Eurasia, and also occurs in smaller form in the Alps and some English lakes. Among those lucky enough to have tasted it, a wild arctic char enjoys a reputation as one of the finest tasting fish in the world. I haven't had that experience, but the farm-raised char I have sampled from farms in the Yukon Territory and western Washington have been among the best farmed fish I have ever tasted. Imagine a very big trout, but richer in flavor and finer in texture, or a small salmon, but paler in color with less fat and a more delicate flavor, and you have a pretty good idea of arctic char. Any cooking methods suitable for either trout or salmon will work with char, although poaching seems especially right for its delicate flavor and texture. If you have occasion to cook a whole arctic char, it's one of the prettiest of the salmonids, with skin of a pale coppery or rosy sheen, yellowish highlights, and faint pink spots. As a bonus, a typical fish of 4 to 5 pounds is the perfect size for a 24-inch fish poacher.
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