Salmon is arguably the most popular fin fish on American menus today. But within the general heading of salmon there are a number of species and subtle variations in appearance, flavor and texture. Salmon available commercially to chefs and restauranteurs in the US, fall into two major groups, Atlantic salmon is typically farm raised, and not always in Atlantic waters. Pacific salmon is mostly caught wild.

Atlantic Salmon: Since the late 1980's the popularity and availability of salmon has risen dramatically. This is due in no small part to the production of farm raised Atlantic salmon.

The Atlantic salmon (salmo salar ) has for centuries been a prized catch on both sides of the Atlantic. Sparkling silver on its sides and belly with a dark back and small spots on its upper side, these fish average 9-10# whole. Its flesh has a deep pinkish- orange color and a firm texture.

Since the turn of the century Atlantic salmon have been in great decline due to pollution and dam building in the rivers where this fish spawns. Once a favorite New England delicacy and bountiful in the waters of the Northeast, it has been almost non-existent in the US, except in Maine.

Pacific Salmon: Five species of Pacific salmon make up a spectrum of availability throughout the year. Each has its season, unique flavor, and texture characteristics.

Chinook Salmon (King salmon): The largest of the Pacific varieties, it ranges from 9 to over 40 lb.. It is silvery and can be distinguished by black spots on its fins and tail. Its principle season is March to October. It is rich in fat and its flesh has a large flake texture.

Chum Salmon (Keta salmon): The second largest of the Pacific salmon, it ranges between 8 and 15 lb.. Chum Salmon are silvery and can be distinguished by its slim "wrist" just above its tail. It is mostly available from July to November. Its flesh is pale in color and moderate in fat content.

Pink Salmon: The most numerous of the salmon species in the Pacific. It has an oval shape making it the roundest shaped salmon. Pink salmon don't usually get much larger than 8 lb.. Landed mostly from July to September most pink salmon are canned. Its raw flesh has a light pink color.

Sockeye Salmon: The second most numerous salmon in the Pacific, its harvests take place in a a relatively short time period centered around the summer spawning season. Copper River in Alaska is one of the earliest and most prized runs of sockeye. Sockeye are prized for their bright red flesh and firm texture. Available June to September they average about 6 lb..

Coho Salmon (Silver salmon): Identified by its silvery appearance, the coho or silver salmon is the smallest of the Pacific salmon. Coho has a finely textured flesh with rich pink color. It is available as a wild catch from June to November. Wild fish range from 4 - 10lb.. It is also notable because it has been successfully farm raised, usually being sold as "plate" salmon or "baby coho" weighing about 8 oz.

Salmon Farming: Starting in the 1970's Norway began developing the technology for farm raising Atlantic salmon. As market demand rose, salmon farming took hold in neighboring Scotland, Ireland and Iceland. By 1990, farm raised salmon were being produced in Canada, Chile, Australia, New Zealand and the US. Domestic salmon farming, done mostly in Maine, is a very small part of the world's production which was nearly 500,000 tons by 1994 according to the University of Anchorage. Today, the salmon producing market is primarily dominated by Norway, Chile and Canada.

What's so great about farm raised salmon? From the chef's point of view, salmon has always been a prized product in the kitchen. But having a consistently fresh and high quality seafood product available 52 weeks of the year has propelled salmon to the head of the seafood category and driven creativity with this versatile fish. From the restauranteur's point of view, its great not to worry about fluctuating prices. The cost of farm raised salmon in most markets hasn't fluctuated more than a dime per pound in the last 3 years. This combination of benefits has made salmon a starring player on fine dining menus.

How are salmon farmed? Through selective breeding, producers are continually developing a better product. Eggs are selected from only the highest quality salmon and incubated in fresh water. Young salmon are allowed to develop in fresh water for about 1 year. They are then transferred to salt water cages.

Large floating cages are anchored in pristine waters near the shore to produce an open water pen for young salmon (smolts) to grow to maturity. A typical cage holds 10 tons of salmon.

A controlled diet of fish meal, processed from herring, is the main food for farm raised salmon. Feed is regulated by body size and water temperature. There is a 1 to 1 ratio of meal to product produced. In other words, a pound of feed will produce a pound of salmon. Salmon farming is a very efficient use of feed compared to land based farming.

Harvesting of farm raised salmon is coordinated with market demand. A week before harvesting feeding stops, this produces a firmer meatier salmon. Salmon are gutted, washed, graded and cut on site and immediately packed in ice in specially designed containers. They are typically shipped within 24 hours of being harvested.

In contrast to all the benefits of farm raising salmon, one negative aspect regularly mentioned is pollution. Large cages densely packed with salmon create an unnatural amount of waste that is not easily absorbed by the ocean's ecosystem. So far, the only solution seems to be regularly moving cages to avoid a build up of salmon waste on the ocean floor.