Dungeness River Research Articles

Re-awakening dormant life history variation: stable isotopes indicate anadromy in bull trout following dam removal on the Elwha River, Washington

Migratory species take advantage of multiple habitats during their life cycle to optimize growth, survival, and reproduction. However, migration also makes them vulnerable to habitat degradation and exploitation in each habitat, and loss of connection between habitats. Partially migratory species (i.e., migration is facultative rather than obligate) can persist after loss of connectivity and may then resume migration after the habitats are reconnected. We analyzed stable isotopes of carbon and nitrogen to investigate the possible use of marine habitats for foraging by bull trout, Salvelinus confluentus, in years immediately after removal of impassable hydroelectric dams on the Elwha River, Washington State, USA. Juveniles in the Elwha River estuary were similar in δ15N and δ13C values to those in the estuary of the free-flowing Dungeness River nearby, and the values of fish from the estuaries were higher than those of juveniles collected in the river, consistent with use of marine food sources. Adult bull trout collected in each of the rivers had values indicating extensive reliance on marine prey - similar to those of adult Pacific salmon that had spent several years at sea. Taken together, these data demonstrate that the Elwha River bull trout, almost entirely landlocked for a century, are rapidly resuming anadromy and that the marine prey contribute substantially to their trophic ecology and likely their growth. More broadly, the results reveal the importance of connectivity for migratory fishes, their ability to resume anadromy once the connection between habitats is restored, and the population resilience that partial migration provides for them.

COOPERATIVE MANAGEMENT OF THE DUNGENESS WATERSHED TO PROTECT SALMON IN WASHINGTON STATE1

ABSTRACT: Over the last decade, the Jamestown S'Klallam Tribe has formed partnerships with their neighboring county government, irrigation districts, property owners, and state and federal agencies in an effort to save the dwindling runs of Dungeness River salmon. Although considerable progress has been made to begin the recovery process, the watershed is included in recent listings of Pacific Northwest salmon under the Endangered Species Act. Under the coordination of an active watershed council, significant improvements have been made in water conservation and the protection of instream flows. Cooperation between the Tribe, irrigation districts and the Washington Department of Ecology resulted in a trust water rights agreement and the reduction of late summer water withdrawals by one‐third.

Microsatellites Reveal Population Identity of Individual Pink Salmon to Allow Supportive Breeding of a Population at Risk of Extinction

Efforts to restore depressed populations of Pacific salmon Oncorhynchus spp. are often hampered by the inability to assign population identity to individuals in an admixture. This knowledge is of particular concern in supportive breeding programs, in which misidentification of individuals to population may result in progeny of mixed heritage, which, in turn, results in the erosion of the genetic population structure and of the existing genetic diversity and local adaptations of the target population. We evaluated two classes of genetic markers, allozymes and microsatellites, for estimating population identity of pink salmon Oncorhynchus gorbuscha in a supportive breeding program on the Dungeness River in Washington State. Fall-run pink salmon of the Dungeness River are the target of restoration, but they presumably overlap, in terms of timing, with an earlier summer run. Both marker types revealed similarly low estimates of relative genetic differentiation (θÌ, = 0.02), which suggests that there is little variation in allele frequency among populations. However, microsatellites provided a more accurate estimate of population identity. When applying a log-likelihood ratio criterion of greater than 1.3, 74.8% of individuals were correctly assigned to population using microsatellites (versus 3.1% of individuals using allozymes). The difference in assignment accuracy was best predicted by the statistic δÌ, which estimates cumulative allele frequency differences among populations. Our results suggest that genetic markers with many alleles are preferred when populations exhibit little genetic differentiation (as is the case in pink salmon), because δÌ, is more likely to be large, presumably as a result of genetic drift at each allele. The use of microsatellites to select fall-run pink salmon for supportive breeding confirmed the run-timing overlap and prevented unintentional crosses between the two populations.

Thinking about Ecology: Cognition of Pacific Northwest Forest Managers across Diverse Institutions

A case study of 48 forest managers in the Dungeness River watershed in Washington State revealed four main cognitive models of the forest ecology of the watershed. Organizing principles for the four models were the concept of wilderness, timber management, forests as habitat or 'home' for humans and animals, and a bureaucratic orientation that incorporated forest regulation and policy. Managers' ecological cognitions varied with multiple personal, institutional, and cultural influences. Managers with a wilderness orientation represented a common wilderness-civilization dichotomy in American thought, while the cognition of managers with a timber orientation appeared to be largely a product of professional training. The habitat orientation coincided with a close economic relationship to the land, i.e., direct use of land for subsistence or income as a farmer or logger. The bureaucratic orientation appeared to develop with experience as a middle or upper manager in public agencies. Considerable diversity in ...

Genetic variation and productivity of Populustrichocarpa and its hybrids. V. The influence of ramet position on 3-year growth variables

A 3-year study was conducted on the effects of different stem positions (from which cuttings were taken on a stool-bed ortet) on sprouting characteristics and stem growth of Populustrichocarpa Torr. & Gray. In 1986 ramets were collected from five stem positions, evenly distributed from the base to the tip, on three stool-bed ortets of each of 30 clones representing three river valleys in western Washington. Each set of five was planted at 1.22-m spacing in one of three adjacent blocks in an experimental field in Puyallup, Washington. First-year results showed that cuttings from the upper two positions tended to leaf out earlier and develop a single rather than multiple stem as compared with those from the lower positions. Analyses of variance of growth traits showed significant position, position–river, and position–clone within river interaction effects. Positional effects on sprouting and growth were strong primarily for material from the Dungeness River. At the end of the 3rd year, the largest Dungeness ramets (from position 2 near the top) averaged 860 cm in height and 7.3 cm in diameter, whereas the smallest (from position 4) averaged 753 and 5.8 cm, respectively. By this time, it appeared that the shorter trees had begun to suffer from competition associated with crown closure. Thus, the impact of competition in a tightly spaced, multiclonal plantation can influence the ultimate growth and survival of different clones and thereby bias a genetic evaluation.