The Question of Hatchery Fish
A report to the Maxwelton Salmon Adventure
by Dean Enell
What's wrong with hatchery fish? For one they're pretty naïve. After spending 2-6 months in a benign hatchery environment they're totally unprepared for the real world and generally become a predator's meal in short order. In fact less than 5% make to it to adulthood. Hatchery fish
are described as those incubated or reared under artificial conditions for at least a portion of their lives whereas wild fish
refers to those produced by natural reproduction in a river basin that has contained a population of that species since 1800.
On a broader scope, some scientists worry that hatchery-raised salmon lack the genetic characteristics wild salmon have developed over generations to adapt to specific rivers and streams, thus threatening their long-term survival. In fact, despite the presence of more than 150 hatcheries along the Columbia pumping out 1 billion juvenile salmon smolts each year, the Columbia River stocks have dwindled from historic highs of as many as 16 million returning adults to fewer than 2 million today.
Historically hatcheries have been part of the Pacific salmon equation since 1872, when the U.S. Fish Commission built the first one on the McCloud River in Northern California. Since then more than 400 have been established from Alaska to California, turning out more than 325 million juvenile fish a year. Unfortunately, from the very beginning, hatcheries ignored the lifecycle that had made wild salmon thrive for 10,000 years since the last Ice Age. Eggs were routinely shipped from as far away as New Zealand, with no regard for the local adaptations the fish had evolved for their home rivers. Gene pools were truncated by spawning a whole generation from the first few fish to come in. While hatcheries are good at producing fish for people to catch, they are not as good at producing fish to survive in the wild, said Reg Reisenbichler, a biologist for the U.S. Geological Survey. To thrive in a hatchery, fish feed aggressively on the top of the water, where their food pellets are scattered. In the wild, that sort of behavior will get a smolt eaten by a kingfisher. As a result, hatcheries genetically change the behavior of the fish, and are vulnerable to booms and busts, said Robin Waples, director of conservation biology at the National Marine Fisheries Service's Northwest Fisheries Science Center in Seattle.
Other fish scientists worry about the effects of staying, or the tendency of fish to reproduce, in areas other than where they were raised. The concern is that hatchery fish with low survival and reproductive rates displace native fish that are more adaptive to a particular area and have greater reproductive potentials. Reference 1 below cites studies that advance this argument.
The earliest hatcheries were simply egg-incubating stations that released tiny fry into the streams, hoping to increase fish populations by reducing the mortality of eggs incubated in stream-bottom gravels. By the second decade of the twentieth century, managers began to feed the fry and raise them to fingerling size before turning them loose. But the diet they received - a mixture of fish offal, horse meat, tripe, and condemned pork and beef - was ineffective, and even spread disease through the tightly packed schools of fish.
It wasn't until 1960, with the advent of pelletized feed made from fishmeal, that hatcheries had significant success in raising large numbers of fish to large fingerling size or even to the smolting stage, when the fish begin to adapt to salt water for their adult lives. Fish were not the only one that had to adapt to this changed food source. In Astoria (Oregon) the most common fish lure these days is fashioned to look like a tiny artificial food pellet (the Oregon Moist Pellet) rather than the traditional insect or egg.
Even as they became more proficient at raising juvenile fish, the hatcheries were actually undermining the vitality of the wild stocks of salmon that they hoped to supplement. One problem was rooted in "carrying capacity," the maximum number of fish that a particular stream can support. As hatcheries infused rivers with millions of fingerlings for their journeys to the sea, the hatchery fry came to compete with the wild fish traveling oceanward at the same time. At times, there simply wasn't enough food to nourish all of the young fish, to the detriment of both wild and hatchery stocks.
When hatchery-bred fish return as adults and interbreed with wild salmon, they produce offspring that are less hardy than their purely wild counterparts. Each river and tributary has a distinct strain of fish, the product of generations of natural selection in which the fish that best fit a particular environment were the most likely to return and reproduce, passing on their genes to the next generation. For instance, fish whose spawning journey takes them just a few miles from the ocean enter the river nearly ready to mate, while their cousins destined for spawning grounds far inland will not be ready to lay their eggs until months after they re-enter fresh water. In addition, wild fish often possess resistance to the parasites and diseases of their native streams.
Sometimes the genetic wires get crossed accidentally, as when hatchery fish stray into another stream upon returning to spawn. In many other cases, managers transplanted fingerlings from one river system to another. Either way, the hatchery-bred salmon mated with wild native fish and diluted their local adaptations. For example, native coho salmon possess resistance to a particular parasite that is present in coastal Oregon's Nehalem River. Young hatchery coho from another river, where the parasite isn't prevalent, were planted in a tributary of the Nehalem for several years. Later, when adults were collected there, their offspring proved less resistant to the parasite than the wild stocks but not as susceptible as the hatchery transplants. Researchers concluded that the mixing of the stocks had reduced the population's resistance to the parasite. In another case, scientists found that eggs laid by coho of hatchery descent that spawned in the wild were less likely to survive than the eggs of wild fish. The reason? Apparently, the hatchery fish were spawning earlier in the year, which was not as well matched to the conditions of that river as the native salmon's timing.
But hatcheries are staffed by fish scientists, and they are well aware of past shortcomings and the role of hatcheries is changing dramatically. Deeper understanding of the problems hatcheries have created and of the role they have to play in the recovery of salmon, and a new recognition of the limits of our scientific knowledge are profoundly changing the way hatcheries are managed.
Today, producing fish for harvesting is balanced with a second mission: to help conserve wild salmon, and, where they are endangered or threatened, to help them recover to healthy, sustainable levels. This mission will take on even more importance in the years to come.
To lay the groundwork for a comprehensive re-tooling of hatcheries, the first-ever scientific review of federal, state and tribal hatchery practices is now underway. Work has begun to redesign some hatcheries to provide safe passage for wild fish. Hatchery operations are timed so that young fish are released when they will not compete with wild fish for food. Guidelines have been developed to protect the genetic integrity of wild salmon, and state, tribal, and federal governments are working together to complete Hatchery and Genetic Management Plans for hatchery operations that may affect wild salmon. An Independent Scientific Review panel has also been asked to develop a scientific framework for hatchery operations.
Already there are examples of how hatcheries can play a vital role in saving endangered wild salmon. In 1976, biologists estimated that fewer than 50 wild spring Chinook salmon remained in the North Fork of the Nooksack River-the result of excessive fishing, timber practices and other factors. To guard that stock against immediate extinction, biologists from the Washington Department of Fish and Wildlife captured these fish and moved them to the nearby Kendall Creek Hatchery. These native salmon are bred at the hatchery, and they return as adults to the hatchery, where they help propagate future generations. A scientific committee, which includes representatives from the Nooksack and Lummi tribes and WDFW, meets regularly to chart the course of their recovery.
For the past five years, an average of 2,000 adult wild spring chinook has returned to the hatchery, and in 1999 an additional 900 fish returned to the river itself. This successful restoration project took many years. But this experience has been the source of new knowledge about how to succeed in the delicate task of preserving and restoring wild fish when they are at the brink of extinction.
Today, one third of the 100-plus hatcheries in Washington state are involved in recovering wild salmon runs. Still, there is a great deal more to do. Some hatcheries are a century old, and urgently need to be improved-in some cases to remove obstacles that block wild fish from migrating upstream. This is work that must be done to bring hatchery practices into harmony with their new, dual mission of recovering wild fish while sustaining the abundance of hatchery fish available for harvest.
The biggest problem with hatcheries is they make people think they can have salmon without worrying about wiping out their spawning habitat with dams, clearcut logging and overgrazing. Until very recently considerably more money has been pumped into hatcheries than habitat restoration under the premise that we could engineer ourselves out of the salmon problem without altering our salmon insensitive practices. Fortunately there has been increased emphasis on habitat restoration lately as the salmon stocks continue to dwindle. Hatcheries which were initially started to 'create more fish,' have also employed better science to reduce the detrimental effects of competition, gene pool dilution and low survival rates mentioned above.
As in Field of Dreams, the baseball movie which popularized the notion of 'if we build it they will come', our goal should be to provide salmon habitat to encourage the return of salmon to the Maxwelton. Using hatchery fish to guage our rebuilding efforts while stimulating community involvement seems a worthwhile course of action. As Jan Holbrook pointed out, even if many of these planted fry fail to survive and return they are contributing to the creation of a fish conducive environment within our watershed by contributing to the natural processes which become involved. If these planted fish become well rooted and pose a competitve threat to returning native fish then we should rethink our planting practices.
My reading of this situation is that we should continue our practices with a limited number of planted fish so we can evaluate the watershed we're attempting to rebuild. As an accessory benefit, we're providing stimulus to the community at large (and ourselves) to participate in this process.
1. NOAA Tech Memo NMFS NWFSC-30: Genetic Effects of Straying of Non-Native Hatchery Fish into Natural Populations
STRAYING OF HATCHERY FISH AND FITNESS OF NATURAL POPULATIONS
Washington Trout and Native Fish Society
P.O. Box 19570
Portland, OR 97280, USA
Opinion from Jim Myron Conservation Director, Oregon Trout