Section 2: Methods

This project focuses on three areas of evaluation: the historical production, the current production and the capacity for restoration. We do not consider these three factors an exhaustive list, but we believe that these factors should be part of any successful prioritization.

Historical production

The historical production gives an idea of the relative capacity of the watershed to produce Pacific salmon. Our index (Table 1A) uses the method devised by Lichatowich and Nicholas (1992). The cannery records from the late 1880s to 1920s are used to determine the historical production (Cobb 1930). Details of the method are as follows:

The largest five years of harvest are averaged
The catch effectiveness was set at 40%
Cases of salmon are converted to numbers by the following formula. For Chinook there are about 65 pounds of fish for each case. And a Chinook is assumed to average about 22 pounds. For coho and chum salmon there are 70 pounds of fish per case, and the average fish weighs about 10 pounds.

The advantage of this approach is that in different watersheds the fishing industry developed at different times, speeds, and to some extent to different levels. By selecting for the largest five harvests over the entire period of the cannery records, an index of historical production that is relatively homogeneous throughout the region is obtained. The down side of using this method is that the capacity of the streams to produce salmon was already significantly impaired in most watersheds before the turn of the century. So, this historical comparison is an indicator of the historical capacity. It is a more equitable comparison of the capacity of watersheds to produce salmon. We used information on coho salmon, chinook salmon, and chum salmon for the comparisons. It does not consider the production of steelhead trout or cutthroat trout. Oregon values were from Lichatowich and Niclolas (1992). Washington values were calculated for this project.

The historical salmon production for each watershed was scored by the following criteria (Table 1A in Section 3). The largest average run of salmon for each species was selected from the watersheds of record. That watershed is then the benchmark for that species, receiving the maximum score for that species. If the species is listed as endangered the score for that watershed is 10 points. If the species is not listed the maximum score given is 5 points. The score of all other watersheds was determined by calculating the percent of that watersheds production compared to the largest population of that species from the list.

For example, for Chinook, the Rogue River had the highest production of Chinook in the region 125,000 fish. In all other watersheds the production of Chinook was divided by 125,000 and multiplied by either 5 or 10 points depending on if Chinook are listed or not.

The endangered status of salmon species came from the ESA web page on February 22, 2001. Species listed as "candidates for listing" were not considered listed. In the case of Puget Sound, most of the fishing occurred in the Sound itself and not in the streams, so the historical production of each stream could not be determined independently. We assumed the maximum production of each species unless watershed size or geology suggested limits. Most watersheds were given the maximum score.

Current production

The current production of salmonids in Pacific Northwest watersheds comes from Oregon Department of Fish and Wildlife and the Washington Department of Fisheries and Wildlife (Table 1B in Section 3). The California Department of Fish and Game does not have population estimates for northern California watersheds. Again, species of salmonids currently listed as endangered were weighed more heavily. The current production estimates will be updated as the information become available. Scoring followed the same method as outlined in the historical section. The watershed with the highest score was selected as the benchmark. For all other watersheds, the proportion of their populations compared to the base were determined and multiplied by 10 points or 5 points depending on whether the fish was listed as endangered or not.

Capacity for restoration

For this analysis we selected three additional factors that significantly influence the opportunities to recover Pacific salmonids: hatcheries, dams, and land use. For this project we term this assemblage of factors as the capacity of watersheds for restoration (Table 2A in Section 3).

Hatcheries

The current populations of Pacific salmon species are a mix or wild and hatchery fish. We are primarily interested in the production of wild fish for this project, because the question we are addressing is, "what are the most important parts of the landscape for producing salmon?" Our interest is landscape scale restoration. If a run is primarily hatchery stock then the run is not primarily dependent on the landscape. Also, available evidence at this time suggests that high proportions of hatchery fish in mixed populations are detrimental to the wild fish for a number of reasons. Hatchery information was obtained from the state agencies for state hatcheries. Tribal hatchery production was not available for all hatcheries at this time. We will incorporate the additional information into the map of restoration priorities as well as update the hatchery information as it becomes available. Also, if a run is almost entirely supported by a hatchery it suggests an underlying mindset that believes that human technology (hatcheries) can replace the watershed for producing salmon (Lichatowich 1999). This mindset establishes a climate negative to landscape recovery.

We obtained the hatchery information from each state (Table 2B in Section 3). The scoring is as follows:

We determined the average current wild production of smolts and juveniles by dividing the number of returning adults by the average ocean survival for the region and set that average as the benchmark for juvenile and smolt production of the hatcheries. We assume that as hatchery production becomes greater than watershed production the major problems increasingly develop. For Chinook this number is 500,000 fish. And for Coho salmon it is 100,000 smolts. For steelhead it is 100,000 fish.
Current hatchery production is divided by the benchmark in #1 and multiplied by 10 points or 5 points depending on whether the species is listed or not.
These scores are added (Table 2B in Section 3).
The score in Table 2B is subtracted from 20 and recorded in table 2. If the hatchery score is greater than 20, a 0 is recorded.

Dams

Dams are a major factor impacting runs of salmonids. Not only do dams block fish runs but they also alter the flow regimes, temperature regimes, and the dynamics of organic matter. The effects of dam location and size were scaled into the matrix. Large mainstem dams have the greatest impact on Pacific salmonids. In constructing the index (Table 2A) a large dam in the lower mainstem was given an arbitrary score of 20, a large mainstem dam further up was given a score of 10, tributary dams were scored 5 points, and small tributary dams were given 1 point. The total number of points was tallied and subtracted from 20. Again if the number exceeded 20 a score of 0 was given for that watershed.

Land use

Lastly, the capacity for restoration was evaluated using the criterion of human development. We assumed that the greater the human development the less likely that significant landscape scale restoration was possible. We used the 1990 population census by hydrologic unit as an index of development (Table 2A in Section 3). The scoring followed the same method as used above. The watershed with the highest population was selected as the benchmark. It was given a score of 0. The proportion of each watershed relative to the base was determined and reported as an inverse of 20. Watersheds with low population score closer to 20.