Multiple Studies Find Wild Salmon Endangered by Hatchery Salmon

The research vol­ume, pub­lished in the May issue of Environmental Biology of Fishes, brings together 23 peer-reviewed, inde­pen­dent stud­ies car­ried out across the entire range of Pacific salmon, includ­ing some of the first stud­ies describ­ing the impact of hatch­eries on wild salmon pop­u­la­tions in Japan and Russia.

The stud­ies pro­vide new evi­dence that fast-growing hatch­ery fish com­pete with wild fish for food and habi­tat in the ocean as well as in the rivers where they return to spawn. The research also raises ques­tions about whether the ocean can sup­ply enough food to sup­port future increases in hatch­ery fish while still sus­tain­ing the pro­duc­tiv­ity of wild salmon.

“This isn’t just an iso­lated issue,” says Pete Rand, a biol­o­gist at the Wild Salmon Center and a guest edi­tor of the pub­li­ca­tion. “What we’re see­ing here in exam­ple after exam­ple is grow­ing sci­en­tific evi­dence that hatch­ery fish can actu­ally edge out wild populations.”

Losing wild fish would mean los­ing the genetic diver­sity that has allowed salmon to sur­vive for cen­turies. Unlike hatch­ery fish, wild salmon pop­u­la­tions have a range of highly spe­cial­ized adap­ta­tions to the nat­ural envi­ron­ment. These adap­ta­tions not only help them return to their home streams to spawn, but also increase their abil­ity to with­stand envi­ron­men­tal changes like increases in ocean tem­per­a­ture and extreme vari­a­tions in stream flows. Hatchery fish, as the name implies, are hatched from eggs fer­til­ized in a con­trolled envi­ron­ment and raised in cap­tiv­ity until they are big enough to release into the nat­ural envi­ron­ment. They lack the genetic diver­sity of wild fish that pro­vides insur­ance against fish­eries collapses.

Hatcheries have been used for many years in an attempt to increase catch in the over $3 bil­lion Pacific salmon com­mer­cial fish­ing indus­try and to off­set losses of wild salmon that have suf­fered seri­ous declines due to dams and habi­tat degradation.

“These stud­ies sug­gest that even more cau­tion is needed to make sure hatch­ery pro­grams keep wild salmon safe, and don’t inad­ver­tently hurt the long term poten­tial of salmon runs,” says Rand.

Since the mid-1970s, large increases in hatch­ery pro­grams in the U.S., Canada, Russia and Japan have released bil­lions of fish into the water. And the increas­ing global demand for salmon has resulted in calls to fur­ther expand hatch­ery pro­duc­tion, espe­cially in Russia and Alaska. In a 2010 open let­ter to Alaska hatch­eries, seafood proces­sors pro­posed increas­ing pink salmon hatch­ery returns by 25%-115% over the next five years. Similarly, Russian hatch­ery man­agers stated in 2010 that Russia is plan­ning to build 23 new hatch­eries that would increase the country’s hatch­ery pro­duc­tion by 66% or 680 mil­lion fish.

“The scale and mag­ni­tude of our cur­rent hatch­ery pro­duc­tion sys­tem is enor­mous,” says Rand. “Five bil­lion juve­nile salmon are released each year world­wide, and the prospect of addi­tional increases in hatch­ery pro­duc­tion is wor­ri­some for the long-term sur­vival of wild salmon.”

Not Just a Local Problem

Scientists are also uncov­er­ing sur­pris­ing inter­ac­tions on an inter­na­tional scale. One of the new stud­ies indi­cates that chum salmon (a type of Pacific salmon) released from hatch­eries in Asia, mostly from Japan, have played a sig­nif­i­cant role in caus­ing declines in a wild chum salmon pop­u­la­tion in remote west­ern Alaska, 2500 miles away.

“Genetic data show that these fish share the same feed­ing grounds in the open waters of the Bering Sea and North Pacific Ocean,” says author Greg Ruggerone of Natural Resources Consultants. “With bil­lions of hatch­ery chum released each year, the abun­dance of adult chum salmon from hatch­eries is now much greater than wild chum salmon, so it is not all that sur­pris­ing that we are see­ing evi­dence of com­pe­ti­tion in the North Pacific.”

This com­pe­ti­tion is likely to get tougher with pre­dicted changes in ocean con­di­tions. Recent cli­mate pat­terns have made ocean con­di­tions tem­porar­ily favor­able enough to sup­port large pop­u­la­tions of salmon, but as these pat­terns shift, the amount of food in the ocean avail­able for salmon could drop sig­nif­i­cantly, mak­ing it even harder for wild pop­u­la­tions to survive.

These results have caused many sci­en­tists to point to the need for a new inter­na­tional agree­ment or treaty to address the expan­sion of hatch­ery salmon in the open waters of the North Pacific.

Many indus­try lead­ers, aca­d­e­mic sci­en­tists and gov­ern­ment agen­cies also high­light the impor­tance of more research to under­stand the full impact of hatch­ery fish on wild salmon. “Wild salmon rep­re­sent the back­bone of the Alaska salmon fish­ery,” says Stew Grant of the Alaska Department of Fish and Game, a con­tribut­ing author to the spe­cial issue. “We need more infor­ma­tion about the impacts of hatch­ery salmon enter­ing our wild salmon rivers.”

“There is no sub­sti­tute for wild salmon. They must be our first pri­or­ity,” says Guido Rahr, President of the Wild Salmon Center. “Wild salmon are an impor­tant part of local cul­ture and a cor­ner­stone of eco­nomic health for fish­ing com­mu­ni­ties. And once you lose the resilience that wild salmon con­tribute to our salmon fish­eries, it’s almost impos­si­ble to bring it back. Given these new find­ings, we urge fish­ery man­agers across the North Pacific to exam­ine the sci­ence and err on the side of cau­tion when con­sid­er­ing hatch­ery prac­tices and expansions.”

Source: Wild Salmon Center Release