Sauteed salmon with morels and peas

With farm-raised fresh salmon available every day of the year, it’s easy to forget that fresh salmon used to be a seasonal specialty. But just as sweet corn, strawberries or watermelon never taste as good as they do at the peak of their local season, there is no better time to enjoy salmon, specifically wild California king salmon, than from now through September.

The California commercial salmon season began May 1, starting south of San Francisco and gradually moving north through Sept. 30. The harvest is organized in this way in large part to concentrate the fishery on the healthiest stocks of salmon, while minimizing the impact on other, more threatened populations.

King, or chinook, salmon, the only salmon fished commercially in California these days, is the largest and most southerly-ranging of the six species of Pacific salmon. However, classifying salmon by species tells only part of the story. Each individual fish can be further identified by the river of its birth, and even the season when its parents spawned. Several different stocks of the same salmon species may enter the same river at different times of year, spawning in different locations. Each of these “runs” represents a genetically distinct population that is finely tuned to its environmental conditions and rarely, if ever, breeds with other stocks.

With this specialization comes vulnerability, and specific runs can become threatened or endangered when their environment changes. The U.S. Endangered Species Act allows for protection of “distinct population segments” within a given species or subspecies, and in salmon regulations these segments take the form of “evolutionarily significant units” (ESUs), which may comprise several similar runs in a geographic area. Two king salmon ESUs are currently listed as endangered and seven more as threatened, but others remain abundant enough to support large-scale commercial and sport fishing.

Most of the king salmon found off Central California originate in the Sacramento River system and belong to the ESU officially known as the Central Valley Fall-Run Chinook. Hatched from eggs laid in October in the main stem of the river and its low-elevation tributaries, these fish migrate downstream as juveniles the following spring, then spend a few months in estuaries around San Francisco Bay before heading out into the ocean. (There is a separate run that enters the river from October to December and spawns in February but is otherwise similar and is managed as part of the same ESU).

In the spring of their fourth year, the now-adult salmon concentrate near the coast, growing rapidly as they feed on abundant krill, squid and anchovies. It is at this point that they are taken by fishermen. Those that escape enter San Francisco Bay beginning in August (once inside the Golden Gate they are off limits to commercial fishing) and migrate upriver to the precise stretch of river where they were born, to lay eggs or fertilize them. Like other Pacific salmon, they spawn only once in their lives, then die.

With their historic migration routes and spawning grounds largely intact, Central Valley fall-run kings constitute one of the largest wild-spawning salmon populations south of Alaska, and their numbers are augmented by hatchery-bred fish. But the winter and spring runs on the same river have not been so lucky. Cut off from its traditional upstream spawning grounds by Shasta Dam, the winter run survives only as a small remnant and is officially listed as an endangered ESU. The spring run, also adapted to higher-elevation spawning, was once larger than the fall run but is now extinct on some rivers and threatened in the others.

To protect the remaining winter-and spring-run fish, the former mid-April opening of the commercial salmon season was pushed back some years ago to May, and the minimum legal size has been raised in the latter half of the season to favor large fall-run fish over younger and presumably smaller winter-run fish.

The current commercial season opening, which runs into late August, is limited to waters south of San Francisco (the actual dividing line being Point San Pedro in Pacifica, San Mateo County), and for the next month or so we can expect Monterey and other Central Coast ports to see most of the salmon landings. As the north-central coast opens in stages from late May through mid-July, the center of salmon action shifts northward to the Golden Gate region and the coasts of Marin, Sonoma and Mendocino counties. On the far north coast, where fish of Klamath River origin dominate, the ocean commercial season will not open until Sept. 1.

In addition to California salmon, we sometimes see wild salmon from the Northwest in summer or kings caught by trolling in southeast Alaska at various times of the year. However, the most famous (and most expensive) Alaska salmon these days comes from a brief but intense gillnet fishery at the mouth of the Copper River in late May and early June. The jet-freight arrival of the first Copper River kings in Seattle has become a local media event like the arrival of Beaujolais Nouveau in Paris, and the hype has recently spread to other cities.

Now don’t get me wrong--these are magnificent, rich-tasting fish, fattened up for their 600-mile spawning run up a long, cold river. But they are not the only delicious spring salmon on the market. Some shoppers and restaurant diners will apparently pay half again to twice as much for Copper River king salmon as they will for king salmon from Monterey or Morro Bay. Hey, it’s your money, but personally, I’ll take the local fish and eat it twice as often.

Salmon is delicious cooked by various methods, from poaching to grilling. Perhaps because of my restaurant background, my first inclination with salmon is to cut it into individual portions and cook them as quickly as possible, whether by grilling over a hot charcoal fire or searing in a skillet and finishing in a hot oven. Both of these techniques give a beautiful browned-orange color and crisp edge to the surface, contrasting with the slightly translucent color of the interior.

However, I have recently come around to the opposite approach, cooking salmon slowly at lower temperatures. You don’t get the crusty outside, but the whole piece cooks to an especially tender, moist texture. Timing becomes less crucial as well.

“Paula Wolfert’s World of Food” (Harper & Row, 1988; re-released in 1996 as the Penguin paperback ‘Mostly Mediterranean’) contains two salmon recipes using a method she learned from self-taught French chef Michel Bras. In what she calls “oven-steaming,” inch-thick salmon filet portions bake on a sheet pan on the upper shelf of a 225-degree oven, with a pan of boiling water on the lowest shelf to provide a moist environment.

Alice Waters’ “Chez Panisse Cafe Cookbook” (HarperCollins, 1999) takes the slow-bake technique a step further, reducing the temperature to 200 degrees and allowing a full hour for a whole 3-pound salmon filet. Again, a pan of water on the lowest oven rack provides a moist environment.

Other published recipes call for temperatures in the 300-to 325-degree range, with proportionally shorter cooking times. A slight variation on this technique is to bake salmon filets on a cedar or alder plank at about 350 degrees. In addition to providing a distinctive smoky aroma, the plank acts as a heat sink, moderating the heat of the oven so the fish takes almost twice as long to cook as it would on a thin metal pan at similar temperature.

I find a dry 300-degree oven to work fine, and I don’t bother with the pan of water. The timing in the recipe here will produce fish that is still medium-rare, with the center firm but still slightly translucent. If you like it less cooked, use an instant-read thermometer and pull the fish from the oven when the internal temperature reaches 105 degrees.

Depending on the fat content of the fish, white fat may or may not collect on the upper surface of slow-baked salmon. Early in the season, wild salmon tend to be a little leaner than they will be later in the summer, and they are definitely leaner than the typical farm-raised salmon. In any case, if you don’t like the look of the white layer, simply wipe or blot it away with a paper towel.

Being especially tender, slow-baked salmon needs something on the plate to provide a texture contrast. Oven-fried potato wedges are one solution, but the ideal oven temperature for the fish is too low to make them without a second oven. Crisp potato latkes cooked on top of the stove are another possibility. But the easiest solution of all is the Indian lentil wafers called pappadums , which toast up crisp in a few seconds over direct stovetop heat. You can lay the dried pappadums directly in the grate of a gas range, turning them with tongs as they puff up and brown. With an electric stove you will need some sort of grate to hold them half an inch or so off the coils; a Mexican-style asador works perfectly.

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Jay Harlow is author of “West Coast Seafood” (Sasquatch Books, $23.95).