Nooksack/NNR/SF5-2 South Fork Nooksack Nutrient Supplementation JITW01-NS-NNR-SF5-2/WWO01-057 Most coastal NW streams and rivers are considered to be oligotrophic, or nutrient poor. Historically rivers and streams along the Pacific coast of North America supported vast numbers of spawning salmonids. Marine derived nutrients(MDN) from salmon significantly enriched freshwater ecosystems, both directly through consumption of eggs, carcasses and fry, and indirectly through incorporation of carcass derived nutrients into trophic pathways. Dramatic decreases in salmonid spawner abundances have reduced MDN inputs to freshwater ecosystems, leading to diminished stream productivity and initiating a negative feedback loop that contributes further to salmonid decline. Dispersal of hatchery excess carcasses is an interim strategy to bolster stream productivity until stocks recover. The objective of this project is to enrich the nutrient base in the South Fork Nooksack ecosystem through dispersal of hatchery-derived salmon carcasses. This project will be implemented according to WDFW and NMFS guidelines for carcass distribution. Nooksack DNRW crews will collect, freeze and store carcasses at a commercial cold storage facility, and will disperse approximately 1,000 carcasses a week for 12 weeks for a target release of 12,000 carcasses (approximately 70% coho and 30% chum salmon). Tagged carcasses will be introduced at four access points along the South Fork Nooksack River from rivermile 13 to rivermile 30 affecting 17 miles of the South Fork. A mix of thawed and frozen carcasses will be used to ensure adequate distribution throughout each reach. Care will also be taken not to conduct dispersal during peak flow events, to ensure maximal carcass retention. Landowners and other interested parties will be informed before implementation with a press release and signage at dispersal points. Watershed benefits: Nutrient enrichment through carcass dispersal benefits a variety of terrestrial and aquatic organisms. Salmonids directly consume both eggs and carcasses, in one study, for example, MDN increased as much as 39% in the muscle tissue of juvenile salmonids following carcass placement (Bilby et al. 1998). Carcasses that are not directly consumed provide indirect benefit through incorporation into trophic pathways, which leads to increased productivity. Sections of the South Fork proposed for carcass enrichment provide transportation, holding, rearing and spawning habitat for chinook salmon fry and yearling spring chinook salmon, abundances of which are critically low in the South Fork Nooksack. Since increased survival of salmonids in both the freshwater and marine environments is associated with larger size, augmentation of the food base for juvenile salmonids rearing in these reaches is likely to increase smolt production from the South Fork Nooksack. Other species will also benefit from carcasses deposited by floods in the terrestrial environment; Cederholm et al (1989) found at least 22 species of birds and mammals that depend on salmon carcasses as a food source. Project monitoring will include marking the carcasses by dispersal site. Dispersal will be monitored with foot survey by DNRW crews and the Restoration Coordinator, during which carcass location will be mapped. Data will be used to qualitatively ascertain within-reach retention and extent of movement downstream. In addition, data from ongoing screw trap operations will be used to compare smolt length, survival and %MDN between years with and without carcass enrichment. Such comparison is necessarily qualitative as differences in growth and survival are confounded by a host of other factors. Accomplishment calculations are the following: 17 miles or 89,760 feet length of river ~300 feet wide channel/riparian area 89760 x 300 = 26,928,000/43560 = 618 acres Note: calculator in database comes up with 492 acres. United States Fish and Wil
