EAST MACHIAS, Maine — When it comes to restoring Atlantic salmon habitats, apparently size matters.

That’s among the lessons learned by the Downeast Salmon Federation during three days of consulting this week with Peter Gray, 70, a Scotsman who is a world expert on restoring wild salmon populations to coastal inland waterways like Washington County’s East Machias River watershed.

Through a grant from the North American Salmon Federation, Gray was in Washington County this week to promote the concept of restocking long-depopulated salmon habitats with young salmon raised in stream-side hatcheries to the size of “parr,” which are significantly larger than the younger and smaller “fry” salmon. The smaller fry salmon are most commonly used in U.S. Fish and Wildlife Service restocking strategies in place in Maine and elsewhere.

“Forget about fry,” Gray tells those who seek his advice. “With fry you lose about 90 percent of what’s raised and released. With parr, you’re producing and introducing top-quality fish that are identically the same as if they were born in the river. You’re raising athletes, with the size and muscle texture and survival-of-the-fittest instincts to swim to Greenland and Iceland and then come back to reproduce in your river.”

Gray has spent 43 years developing and testing techniques and technologies that have restored salmon fisheries throughout the world. His methods and oversight during 27 years as manager of the Kielder salmon hatchery are credited with restoring the salmon population of England’s River Tyne in Northumberland, near the Scottish border. Raw sewage and other pollutants had devastated River Tyne salmon to the point where there were no salmon taken by rod in 1959. Annual rod catches are now pushing 5,000, and the Tyne boasts the best recovery rate of restocked fish in Europe.

“It was dead by the 1960s,” Gray said. “Now it’s the best salmon river in England or Wales. But clean water doesn’t make salmon; salmon make salmon. The biggest problem salmon have is us, directly or indirectly. People are the bloody problem, and it’s a duty that we restore them. It’s the right thing to do. We did the damage, and now we have the facilities and the knowledge to repair that damage, so let’s get it done.”

The 450-member Downeast Salmon Federation is in the midst of constructing a $1.25 million fisheries restoration, laboratory and conservation hatchery within a riverside facility in East Machias. The project involves remodeling a building donated by Bangor Hydro-Electric Co. and retrofitting it to accommodate the flow of river water through a hatchery that is rearing 50,000 Atlantic salmon fry a year for introduction to the East Machias River. The hatchery is scheduled to take delivery on 90,000 salmon eggs in January and expects to introduce those young salmon into the river next fall.

Alan “Chubba” Kane, president of the federation’s board of directors, said the East Machias Aquatic Research Center could incubate as many as 600,000 salmon at the facility each year if it could acquire that many eggs through federal fisheries agencies. Historically, he said, restocking strategies that use fry have not shown good results. Kane is eager to persuade the U.S. Fish and Wildlife Service to explore other options, including using parr, not fry, in restocking programs..

“It’s a breath of fresh air to have Peter Gray’s expertise here,” Kane said Wednesday. “This guy is a gift from the sky. He’s put everything together. He’s lived it. He’s found out how to do it. Now it’s a matter of convincing U.S. Fish and Wildlife and other people of that. We want them to help us so that we can help them look good. We have the infrastructure in place. From a cost basis, it would be a huge bang for a small amount of investment.”

Antonio Bentivoglio, a fish and wildlife biologist at the U.S. Fish and Wildlife Service office in Orono, said Thursday that fall parr stocking is already among the methods being used in the Pleasant and Narraguagus rivers in Washington County.

“It’s one of many different approaches we are currently doing,” Bentivoglio said. “We’ve been doing it long enough now to know the results look good. If it’s a better method than egg planting or fry or parr stocking, I can’t say.”

Joan Trial, a fish biologist with the state’s Department of Marine Resources, said the effectiveness of different restocking strategies varies with the locations involved. Fry grow to about an inch in length over the first eight months of their life cycles and are just beginning to feed when they are released in June. Parr, she said, grow to about 2 inches in length by the time they are released at a year old in October. “They have been feeding for months,” she said, “but those are the best months, given the water temperatures.”

“It’s all about the conditions in which we are using them,” she said. “We are constantly evaluating the effectiveness of each approach we use in restoring populations.”

Gray describes salmon as “the most political fish that swim.” It’s a reality that Gray has watched play out in Iceland, Germany, England, Ireland and other countries working on salmon population restoration. “It’s politics that is stopping progress,” he said.

Kane is convinced that the East Machias River watershed offers a superior habitat over other nearby Down East river systems, including the Narraguagus, the Pleasant and the Machias rivers, all of which are more prone to pollution by agricultural chemical runoff.

“Because the East Machias River system’s waterways are pretty remote, they remain more in their natural state,” Kane said. “The upstream lakes are hard to reach, and salmon habitat that is hard to reach doesn’t change much.”

Kane said his group’s goal of seeing the East Machias River teeming with salmon would have a significant impact on the region’s struggling economy in the form of increased revenue for local lodging and restaurant businesses and other businesses that cater to outdoor tourism traffic. Gray agrees.

“You wouldn’t believe the number of rich businesspeople from the south of England who travel to the areas along the River Tyne to fish for salmon,” Gray said. “The impact on the local economy is huge and growing.”