Nothing threatens the salmon’s future more then human development. Stream channels, road construction, timber harvesting, and mining all degrade salmon spawning and rearing habitats. Salmon stocks have drastically declined because of these. Logging areas around streams where salmon live reduces the shade and nutrients that salmon eggs greatly need, so starving the developing eggs. Also it increases the amount of silt in the water which chokes the developing eggs and reduces young salmons’ survival during their migration to the ocean. Controlling all these things will help the salmon make a drastic comeback.
The biggest threat of all to salmon is dams, which kill 50% of young salmon and 20% of adult salmon. Dams and reservoirs make salmon journeys even harder and more hazardous and block the movement of salmon which is the main reason why stocks have declined. They have to navigate through spinning turbine blades and high water pressure that kill and injure salmon. Salmon can also get lost in reservoirs which can make a 2-week journey into a 3-month journey. In Washington’s Snake and Columbia rivers, salmon must pass through 8 dams which kill 80-95% of salmon! Also 70% of these two major rivers which is about 482 miles have been converted into reservoirs! Most scientists agree and I think you will too, that removing dams is the only option to save salmon stocks. So by controlling salmon habitat degradation, improving water flow speeds, lowering water temperature, and removing dams the salmon are sure to have a brighter future ahead.
This is why the Rogue Waters project is critical. We have got to start educating and informing people of the dangers of total salmon decimation.
However, salmon do not transport nutrients unidirectionally from oceans to fresh waters as adults returning to spawn. The migration of salmon smolts from fresh waters to the ocean represents a flow of nutrients from fresh waters to the ocean. The term smolt refers to juvenile salmon that have undergone the physiological and behavioral changes that occur prior to migration to marine or estuarine ecosystems (Groot and Margolis 1991). Juveniles of some species and populations of salmon migrate out of fresh waters immediately after emerging , while other species and populations spend up to several years in fresh waters prior to migration (Groot and Margolis 1991).
This aspect of nutrient transport by anadromous salmon is usually ignored (e.g., Larkin and Slaney 1997; Gresh et al. 2000), or dismissed by citing that from 95% to over 99% of the mass of anadromous salmon is acquired in the ocean, implying that smolt nutrient export from fresh waters is inconsequential. However, this assumes that the number of smolts leaving fresh waters is equal to the number of adults returning to fresh waters, even though ocean mortality of smolts is often substantial (e.g., >80%; Burgner 1991). To the best of our knowledge, no study has systematically analyzed the export of nutrients from freshwater systems by
smolts across systems and years. However, in previous studies of a specific system it has been estimated that smolts export from 6.7% to 24.2% of the nutrients that their parents imported (Donaldson 1967; Naiman et al. 2002). Thus, how much of the nutrients imported to fresh waters by returning adults is exported by out-migrating smolts remains unknown. In other words, while previous studies have quantified the nutrients that adult salmon transport to fresh waters (Larkin and Slaney 1997; Schmidt et al. 1998; Gresh et al. 2000), we do not know how salmon impact net nutrient transport. For these reasons researchers quantified the relative magnitudes of nutrient transport by out-migrating smolts and returning adult sockeye salmon. Using historical smolt and adult escapement data from four major sockeye salmon nursery systems in Alaska, there researchers calculated the amounts of nitrogen and phosphorus that anadromous sockeye salmon import to and export from fresh waters, using a total of 76 years of data from four different systems. Based on these calculations, we found that sockeye salmon are consistent net importers of nutrients to fresh waters, but that out-migrating smolts often export a substantial fraction of the nutrients that their parents imported, and that the percentage exported varies considerably across space and time.
Long story short, the salmon are the honey bees of the rivers, streams and estuaries. Without them nutrients are not carried where they are needed. Man is their greatest threat.Shouldn't we then be their greatest hope?
