Egg&Smolt® 2.1

U.S. Salmon Digest
Volume 2, Issue 1
Summer 1989


Looking Forward: An Interview with Lauren Donaldson

E&S - Tell us about the beginnings of the Donaldson trout at the University of Washington.

Donaldson - In retrospect it is hard to realize the changes that have taken place in Salmonid aquaculture in the past 60 years. When I came to the University in 1930 the usual hatchery practice was to rob a lake or stream to obtain eggs from the wild fish, carry them to the hatchery where they were incubated, reared for a short time and then dumped back into a lake or stream where survival would be minimal.

It seemed obvious to some of us that if real progress was to be made we would have to develop select broodstocks to take advantage of the fantastic versatility in the salmonid gene pool.

As a first step we had to develop the facilities and techniques to rear the fish in captivity, especially an adequate diet. The wild fish that we obtained from Packwood Lake grew very slowly, about 1/10 pound in weight at 2 years of age and maybe a pound by the 4th year when they were mature, and spawned 400-500 eggs.

By improving the rearing techniques and selection for rapid growth we were able to develop rainbows that reached maturity in two years, weighed an average of 10 pounds and produced 10,000 plus eggs.

E&S - Donaldson trout has an extraordinary yield.

Donaldson - These trout not only grow fast but utilize food efficiently and dress out well. Large wild trout, i.e. steelhead, are long and slender with a weight to length ratio of about 1:1 while the select rainbow with their very thick bodies are 1:1.8. Especially useful is the very thick abdominal wall that produces a nice thick slab of fish for the market.

E&S - Are they steelhead or rainbows?

Donaldson -I guess it is a matter of definition. The original stock came from a fresh water lake where the fish had no access to saltwater. For years we have produced inter-racial hybrids by crossing the UW rainbows with steelheads (migratory rainbows) in the hope of producing a fish that would take advantage of both races, including the ability to adapt to salt water. Several years ago we sent some of our select rainbow stock to Norway to the Institute of Fisheries in Bergen. Dr. Gunnar Rolofson, the Institute Director, to my great surprise transferred the young fish to some floating pens in salt water where they grew like gangbusters. When I visited Dr. Rolofson and saw the rainbows thriving in seawater it was the surprise of my life.

This adaptability to salt water of the rainbow stock has since been exploited to develop large commercial industries in Norway, Finland and Japan.

E&S - What do you think of the constraints on development in Washington State?

Donaldson - That is a very difficult question that I don't have a ready answer for. For many years we used the surplus fish from our experimental hatchery to stock lakes in the state, especially Lake Washington, where they did extremely well. At times we released a few hundred gigantic broodstock into Green Lake where they created a real traffic jam.

The best use for these rapid growing fish has been in salt-water net pen culture, a practice very economically successful in many countries but frowned upon in Washington.

E&S - Why did they stop stocking them?

Donaldson - It was a high-level management decision. Since the rainbow are raised in the Lake Washington watershed, and Lake Washington has a very major population of sockeye salmon that are infected with the IHN virus, other fish from the watershed are suspect.

E&S - Which virus?

Donaldson - IHN is a virus that is often found in sockeye salmon. Many years ago we used to see all the symptoms of what is now known as IHN in the old U.S. Bureau of Fisheries hatcheries at Lake Quinault and Birdsview on the Skagit River. While IHN is a real problem I feel it will always be with us so we must learn to work around it. In Alaska where IHN is found in wild stocks of sockeye, Ken Robertson has developed ways of minimizing the effects of the disease.

E&S - Are Donaldson trout stocked elsewhere in the United States?

Donaldson - Many states use these trout, usually in specific management situations. For example, the State of Minnesota maintains a special broodstock at one of their hatcheries. Their practice is to clean out lakes that are too warm for ordinary trout and too cold for pond fish. The lakes stocked with these very hardy fish produce some spectacular trout fishing.

E&S - If you were going to start on a new species now, as you did sixty years ago, what species would capture your imagination?

Donaldson - Again a very difficult decision. Among the salmonid fishes I think sea run cutthroat would head the list. It is possible to develop a very much expanded sport fishery for this very unique fish.

In addition to fish there are very explosive programs with other organisms that are of great interest. Oysters are becoming an exciting area of practical research. The production of triploid oysters greatly increases the market season for a quality product. Hybridization is used to produce oysters for special markets. The development of very productive shellfish hatcheries makes not only an expanded oyster business possible but clams, mussels, scallops, etc.

Of course the biggest marine farming venture is kelp. In China 400,000 metric tons of dried kelp were raised last year. Kelp is 90%+ water-so the weight of the original product is fantastic.

E&S- What is the future of salmon trout compared to Atlantics, coho, and chinook?

Donaldson - I'm a farmer, and any farmer knows that you diversify to survive. I think each of the salmon and trout can make a contribution. If you blend the stock selection properly you can get more production from your facilities, use your labor pool to better advantage, and spread the marketing.



Donaldson Steelhead: Designer Fish for the Seafood Market
Lauren Donaldson designed his trout to please both the aquaculturist and the seafood connoisseur. Eyed eggs were initially shipped from the University of Washington to Norway and Sweden in the early 1960's. In Scandinavia the hybrid was commercialized and raised in ocean net pens. Today that industry produces more than 30,000 metric tons of large Donaldson steelhead annually, with Finland providing more than half the production.

The product has also been well received in the seafood market. In the United States the product is marketed as salmon trout and more than 1,000 metric tons of the fresh product is imported annually from Scandinavia. In continental Europe, the salmon trout has become extremely popular among the smoking operations, which produce specialty products such as lox and gravlox. These smoke houses prefer salmon trout to Atlantic salmon because of its competitive price and intrinsic qualities.

Intrinsically the salmon trout possess a number of attributes for the production of quality lox. The hybrid's small head and high meat to bone ratio yields a fillet of at least 5 percent more weight than from a similar-sized Atlantic salmon. Similarly the Donaldson, due to its short and deep body form, produces a relatively wide fillet for its weight. This is a positive factor for the lox producers since a relatively small fillet can be cost effective for a presliced product. In addition, the salmon trout differs from the Atlantic salmon in showing a lower accumulation of lipids in the muscle tissue, which gives a firmer smoked product with a higher yield during the slicing process.



The Donaldson: "Cafe Juanita"
Peter Dow, proprietor of the popular Cafe Juanita in Kirkland, Washington, shared his recipe for Donaldson steelhead with Egg&Smolt.

Clean and fillet the fish, then let them set for one day before cooking. The fish will drain fully and will be much tastier. Broil the fillet, flesh down, to sear and seal the surface, then turn the fillet, skin down, to complete cooking.

Baste with a light sauce of butter, garlic, lemon, and marjoram. The sauce should not be too tart so that the delicate flavor of the herbs can come through. If fresh marjoram is not in season, chopped chives can be substituted.

"We call them Donaldson Trout," Dow explains, "even though they taste more like salmon than trout, because there is some consumer resistance to the word steelhead." Dow, who has been serving the Donaldson for about four months, adds that "the Donaldson has the same color as salmon when cooked, and people think of it as salmon rather than trout. It's more moist than salmon, too, with a flavor that is less intense." To try Peter Dow's original cuisine, visit Cafe Juanita at 9702 NE 120th Place in Kirkland, Washington, on the eastern shore of Lake Washington.