Some Highlights from Saving Salmon

The current effort to save the salmon is concentrating on the river physical habitat, (i.e., riparian zones, water temperature, condition of the river bottom, rip-rap, culverts, obstructions, etc.). Simply stated, the survival of any species depends on three factors: food, predators and physical habitat. Physical habitat is about 30 percent of the problem. Salmon spends 2/3 of his time in the ocean, thus the ocean represents about 20 % of the total problem and the remaining 10 % is divided between the rivers and the estuaries. See the figure top right. Therefore, the river physical habitat represents about 5% of the problem. The probability of successfully solving a problem by working on only 5% of the problem alone is exceeding low.

By counting the relative abundance of sardine, anchovy, hake, saury, and mackerel scales at different depths in these ocean sediments and comparing them to present stocks, estimates of past abundance of these five fish can be determined over the last 200 years. It is interesting to compare this data with the historic Columbia River salmon catch data. See the curves bottom right. The red curve is the Columbia River Salmon catch data and the green curve is plot based on the fish scale abundance. The duration and similarity of the population trends exclude coincidence as a possible

explanation. They are definitely linked and what caused the decline in one most likely caused the decline in the other. Possible connections might be:

> The six species have a common food source that is declining,
> The six species have a common predator that is on the increase,
> All of the above.

Studies on 23 tributaries to the Columbia River show that popular human conceptions of proper river habitat are not the same as the salmon‘s conception of proper river habitat. Streams with “poor” and “bad” habitat are outproducing streams with “good” habitat. What humans consider as excellent stream habitat is available, but is not being used by salmon.

We have been using incomplete science to save the salmon for 100 years; maybe we should begin to listen to the Salmon. To learn more download the full sixty-two page report.