published scientific literature and what is known and needed by professionals actively working to rehabilitate aquatic resources in Oregon urban and rural residential areas. IMST (2012) summarized what was learned at that workshop and stimulated these two Fisheries articles, as well as a book (Yeakley et al., 2014).
Analysis of gut contents shows that juvenile (30–50 mm) chum salmon (Oncorhynchus keta) in Puget Sound select epibenthic organisms as their primary prey. Harpacticoid copepods numerically comprised over 80% of their natural diet in two areas studied, while terrestrial insects and cladocerans were most important in a third area. Calculation of Ivlev (1961) electivity coefficients indicated high selectivity factors for harpacticoids at one site (+0.59 to +0.94). Comparison of fish gut contents with quantitative epibenthic pump samples of available prey shows that prey selection was size related, but opposite that currently reported in the literature (e.g. Brooks and Dodson 1965); that is, the smaller of the available prey was preferred. This was true for both the total available prey size spectrum and the harpacticoid copepod fraction of the prey spectrum. Large numbers of prey eaten per fish suggest that juvenile chum salmon may exert high predation pressure on nearshore epibenthic organisms in Puget Sound during spring.
Pink and chum salmon (Oncorhynchus gorbuscha and O. keta) fry and Clarke–Bumpus plankton tows were collected from three beach areas in Puget Sound in spring 1970. Chum fry and benthic pump samples were taken in 1971. The diets of the young of the two species were similar. Epibenthic harpacticoid copepods were the chief prey of the chum and pink salmon (57 and 36%, respectively, in 1970). Distinct differences were apparent, the more notable being the preference for invertebrate eggs exhibited by the pinks and the higher preferences for small gammarid amphipods and harpacticoids exhibited by the chums. The stomach contents showed no resemblance to the plankton hauls taken in the same area. The onshore stage of development appears to be a distinct ecological stage in the life cycles of these species.
Previously we examined how degraded urban streams can be rehabilitated, with emphasis on identifying solutions that match the scale of the problems (). Our findings showed that rehabilitation techniques are challenging but that some environmental benefits can nearly always be obtained regardless of existing conditions. Although rehabilitation is useful in many present‐day situations, biologists need to consider the future and think about ways of preventing or reducing future environmental damage. We need to reduce future damage because urban areas are likely to expand greatly over the next century; if historical patterns continue, the number and length of streams experiencing urban stream syndrome will increase, with resulting high repair costs. However, there are several ways of avoiding or mitigating damage that are not only cost effective but provide benefits to humans and urban ecosystems.
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