Strategy: Increase abundance of particular fish species
Issue: Fish Populations
One of the oldest ways to mitigate the effects of dams and other practices (such as logging and commercial fishing) is to build hatcheries. Here, millions of fish are born and fed until they can be released into the river.
Since the mid 1980s, for instance, two to three hundred million juvenile salmon have been released into the Columbia River basin each year. As a result, hatcheries currently account for over 70% of salmon stock in the Snake and Columbia rivers.
The use and operation of hatcheries, however, has become controversial. Possible consequences of relying on hatcheries to keep the abundance of salmon high include 1) reducing the genetic diversity between salmon stocks, 2) hatchery salmon “mixing” with wild salmon and thus further diluting the natural population, 3) changes in behavior that occur from being raised in a hatchery environment, 4) ecological problems because nutrients from wild salmon carcasses no longer fill stream beds, 5) wild salmon smolts being at a competitive disadvantage when looking for food because hatchery salmon are larger when released, and 6) the introduction of diseases that began at hatchery facilities.