State of the Salmon works with resource managers, researchers, fisheries and conservationists on both sides of the Pacific Ocean to help people understand the role of hatcheries in salmon fisheries and ensure that management strategies are designed to protect the health, diversity and abundance of wild (naturally spawning) salmon.
While hatcheries have a role in both recovery of wild fish and increasing fishing opportunities, hatcheries can put wild stocks at risk. The US National Oceanic and Atmospheric Administration (NOAA) Fisheries Service has identified a number of risks to wild salmon from hatchery production.
Genetic risks have been well studied and include interbreeding and intentional or artificial selection that can lead to a loss of genetic diversity in wild populations. This can increase the risk of population declines and fishery closures. Ecological risks, such as competition for food resources are less well understood, but a series of recently published peer-reviewed studies that stemmed from a 2010 conference demonstrate growing scientific evidence that ecological interactions between hatchery and wild salmon can harm wild fish.
New Pacific Salmon Research Points Toward
from Hatchery Fish
May 14, 2012 -- A newly published collection of more than 20 studies by leading university scientists and government fishery researchers in Alaska, British Columbia, Washington, Oregon, California, Russia and Japan provides mounting evidence that salmon raised in man-made hatcheries can harm wild salmon through competition for food and habitat (see press release).
Selected Study Highlights
- In Russia, hatchery chum salmon on Iturup, part of a remote island archipelago in the Western Pacific, appear to be displacing wild chum salmon in neighboring rivers, representing a loss of biodiversity (Zhivotovsky et al. 2012).
- In Japan, where billions of hatchery fish have been released since the 1940s, scientists have initiated river surveys and, for the first time, documented chum salmon that are naturally-reproducing (Miyakoshi et al. 2012).
- In Alaska, hatchery pink salmon are showing up in rivers at levels that are much higher than previously thought. Hatcheries in Alaska have been deliberately positioned to keep them separate from wild stocks. However, the levels of hatchery salmon in spawning populations in many areas of Prince William Sound exceed all commonly used risk thresholds (2-10% hatchery-origin salmon in the spawning population). While the overall effect of this level of hatchery straying remains unclear, a number of scientists are raising concern about the potential impact on wild salmon populations (Brenner et al. 2012, Grant. 2012).
- In Russia, a scientist recommends caution over further expansion of pink salmon hatcheries in Sakhalin until more is known about impacts on wild salmon. The research questions whether current hatchery operations are resulting in net benefits (above wild, background levels) to the pink salmon fishery and documents the decline of a wild chum salmon population in Sakhalin as a result of a hatchery. Hatcheries for chum salmon may have a role given loss of critical spawning habitat for the species in Sakhalin (Kaev. 2012).
- In Russia, investigators reveal that life history traits of hatchery salmon (for example, age of fish in the spawning run) are diverging significantly from their wild counterparts, indicating hatchery fish are becoming domesticated. In addition, the hatchery contribution to the natural chum salmon spawning populations is very high in one intensively researched river system, exceeding risk thresholds used in North America (Zaporozhets and Zaporozhets. 2012).
The research, published May 2012 in Environmental Biology of Fishes, identifies several pragmatic ways to minimize impacts of hatchery salmon on wild salmon. These include:
- Positioning hatcheries so that they are far away from wild populations and timing releases to ensure that they minimize interactions with wild populations.
- Avoid moving hatchery fish to distant release locations to assure they return to their origin at the hatchery, thus reducing the number of returning hatchery fish that stray from the hatchery and enter wild salmon rivers to spawn;
- Marking 100% of hatchery juveniles so these fish can be carefully monitored and traced throughout their life cycle;
- Establishing wild salmon management zones; and
- Establishing caps on hatchery releases to minimize interactions that are recognized, or strongly suspected, to have a negative effect on wild salmon.
See the full press release.
See abstracts of all 22 studies.
Purchase collected series.
What is a hatchery?
Hatcheries are facilities where salmon are bred and raised in captivity for at least part of their life cycle. Hatcheries mix sperm and eggs from returning adult salmon under controlled conditions, incubate fertilized eggs in a regulated environment, raise hatched fish in holding tanks and/or net pens for varying lengths of time, and then release the juvenile fish into rivers or the ocean.
Where are hatcheries located?
While salmon hatcheries have existed for over 100 years, industrial scale hatchery production began growing steeply in the 1970s. Currently, approximately 800 hatcheries in the United States, Canada, Russia, Japan and South Korea release more than five billion juvenile fish annually of all seven species of Pacific salmon (pink, chum, Coho, Chinook, sockeye, steelhead and masu) into the North Pacific Ocean.