found that 78 percent of their diet was comprised of salmon flesh and eggs. A separate study on juvenile salmon growth rates found that fish that received nutrients from carcasses expe- rienced growth rates that were 10 to
In addition to pro- viding a directly consumable food source for young salmon, these carcasses also
provide valuable and necessary nutrients for the trees and plants that are found on the riverbanks.
NELLO PICINICH
150 times higher than fish in untreated control sections. Even on the low end, growth rates were 10 times higher. These salmon carcasses increase the size and health of juvenile salmon as they overwinter in their natal streams. They also provide a food source for the fish immediately after they hatch and swim out of the gravel. In addition, access to these nutrients during the spring time allows salmon smolts (teenagers) to “super charge” them-
selves before their long, hard journey to the Pacific Ocean.
BENEFITS TO THE ECOSYSTEM
As a salmon carcass breaks down, it leaches nitrogen, phosphorus and car- bon into the water, gravels and soils. In addition to providing a directly con- sumable food source for young salmon, these carcasses also provide valuable and necessary nutrients for the trees and plants that are found on the river- banks. One study found that surround- ing trees and shrubs near salmon spawning streams derived more than 20 percent of their foliar nitrogen from salmon carcasses. These trees in turn benefit salmon by increasing shade, increasing bank stability and maintain- ing an overall healthier watershed. Studies have shown that
these
nutrients also directly and indirectly increase the population, production and size of the aquatic invertebrates (bug life). One study documented that aquatic invertebrate populations in- creased eight-fold after the placement of salmon carcasses. These bugs in turn provide another important food source for rearing juvenile salmon.
Other species of wildlife also benefit directly from these carcasses. Salmon
SOUTH PUGET SOUND SALMON ENHANCEMENT GROUP 18
www.joincca.org TIDE
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