The Pacific Rim Project

The Pacific Rim Project first began collecting relative abundance information for the Russian Far East on a river-by-river basis while based at Oregon State University. By the time the project moved to the Wild Salmon Center, we had amassed partial relative abundance data for just two Russian jurisdictions. Salmon abundance is not routinely assessed for river basins in Russia and North America, though abundance estimates are calculated for major commercial river systems.

No harvest or abundance data is available for non-commercial species, other than best expert judgment. Dolly Varden harvest data exists for some jurisdictions. Steelhead-rainbow trout abundance data is not presently available for Western Kamchatka. Steelhead and rainbow trout, though forms of the same species, have been assessed as separate populations by North American biologists. Masu salmon harvest was not tracked separately from other Pacific salmon species until the 1990s.

In 1999, the Wild Salmon Center surveyed regional biologists to gather relative abundance by species and salmon biogeographic zone (ecoregion), as a component of our stock status assessment. We chose to use abundance classes, rather than actual values, given that actual values are unavailable for most river basins and SBZs. Secondly, the use of abundance classes for large geographic areas was more palatable to the Russians, for whom basin-specific abundance estimates are considered proprietary information unless they are available in published sources.

Best-expert judgment relative abundance surveys were completed for all areas of the North Pacific, with the exception of Magadan, Kamchatka, Sakhalin, Alaska, and Japan. For these areas (except Japan), relative abundance was calculated on the basis of long-term harvest trends. Abundance values represent total abundance, including harvest and escapement. The abundance classes used in this analysis are:
1< 1,000 fish per salmon biogeographic zone
2< 10,000
3< 100,000
4< 1,000,000
5< 10,000,000
6> 10,000,000
-9998 signifies that the species has been extirpated from that ecoregion, and -9999 notes that the abundance has yet to be assessed.

Harvest-based relative abundance estimates for Magadan are based on Table 7 from (Ianovskaia, Sergeeva et al. 1989). This source represents the first-ever compilation of historic salmon harvests for the Russian Far East, from 1907-1986. For Magadan, the base years for calculation of long-term average harvest are 1934-1986. Prior to 1934, all species other than pink and chum were lumped together as "other". The "other" category persists in the data after 1934, and likely includes coho, chinook and white-spotted char. Relative abundance was also calculated for anadromous Dolly Varden, which is considered a commercial species in much of the Russian Far East. Weight conversion factors for Dolly Varden are taken from data tables prepared by Dr. Igor Chereshnev for the Pacific Rim Project.

After calculating long-term average harvests, I converted the average tonnages to 1000s of fish, using the conversion weights from Table 21 of North Pacific Anadromous Fish Commission (1997). The next step was to estimate total run size, including escapement. For all analyses, I used a 60% harvest exploitation rate. This may overestimate harvests during some periods, but should be relatively representative over the long-term. The relative abundance results calculated for Magadan were attributed to TO SBZs 17 and the western half of SBZs 18 and 19.

Ianovskaia, Sergeeva et al. (1989) breaks Kamchatka harvests out into two regions – Western and Eastern Kamchatka. Western Kamchatka data are from Table 4, Appendix 2. The base years, as for Magadan, are 1934-1986. I followed the same protocol as for Magadan, but the "other" category was used to assess relative abundance of masu or "cherry" salmon. Weight conversion factors for masu were drawn from (Semenchenko 1989). The resulting relative abundance classifications were attributed to SBZ 21 and the eastern portion of SBZs 18 and 19.

Eastern Kamchatka data are presented in Ianovskaia (1989) Table 4, Appendix 1. The resulting relative abundance classification is attributed to SBZs 23 and 24.

Data for Sakhalin and the Kurile Islands is drawn from Ianovskaia (1989) Table 5. Base years for Sakhalin are 1946-1986, beginning after the transfer of southern Sakhalin and the Kurile Islands to the Soviet Union from Japan after WWII. The protocol followed to estimate relative abundance were the same as for the regions above. The resulting relative abundance classifications were attributed to SBZs 9-13 and SBZ 22, excluding the portion of SBZ 9 on Hokkaido.

Alaskan harvest data was taken from (Byerly, Brooks et al. 1999). Average harvests were calculated for the finest management areas presented in the report. The base years used to calculate long-term average harvests were 1920-1997, except for western Alaska — Kotzebue, Norton Sound, Yukon and Kuskokwim management areas. Salmon stocks were not fully exploited in this region until after Alaska attained statehood. A 60% exploitation rate was used, as for the Russian relative abundance estimates.

Relative abundance was not estimated for Japanese Pacific salmon (chum, pink, masu and land-locked sockeye, or kokanee) or other salmonids (SBZs 1-3, 8). Japanese biologists have very little information about wild salmonid populations of any sort. Estimates based on historic harvest could be made for chum salmon, based on existing information. However, over 95% of Japanese chum salmon production is of hatchery origin, thus the analysis would not speak to the productive capacity of Japanese river ecosystems. Secondly, pink and chum salmon harvests are lumped in Japanese statistics, rendering them ineffective for this analysis. Kokanee are not abundant in Japan. Similarly, we have no abundance data for North or South Korea (SBZs 4-5), which are not major salmon producers though they do have chum and masu salmon runs.

Dr. Xan Augerot, 2002
Wild Salmon Center

References

Byerly, M., B. Brooks, et al. (1999). Alaska commercial salmon catches, 1878-1997. Juneau, AK, Alaska Department of Fish and Game: 66.

Ianovskaia, N. V., N. N. Sergeeva, et al., Eds. (1989). Ulovy tikhookeanskikh lososei, 1900-1986 gg/Harvest of Pacific salmonids. Moscow, VNIRO.

North Pacific Anadromous Fish Commission (1997). Statistical yearbook 1993. Vancouver, Canada, North Pacific Anadromous Fish Commission,.

Semenchenko, A. I. (1989). Primorskaia sima: populiatsionnaia ekologiia, morfologiia, vosproizvodstvo / Primorye masu: population ecology, morphology, reproduction. Vladivostok, DVO AN SSSR.