Figure 1. Study area

1. m. vinson Figure 1. Study area Figure 2. BugLab salmonfly collection locations in the western United States. The Tragic Disappearance and Hopeful Return of Salmonflies to the Logan River A Story of Loss, Despair, Hope, and Community The BugLab & The Cache Anglers Study area The Logan River Basin is composed of two major tributaries, the Blacksmith Fork and the Logan River. These two rivers are remarkably similar with respect to their discharge and temperature regimes, chemistry, and biota. Basin vegetation is primarily coniferous forest and aspen at higher elevations, sagebrush at mid-elevations and agricultural and urban plantings at the lowest elevations. Historical and present land uses in the basin are livestock grazing at the upper elevations and agriculture and urbanization at lower elevations near Logan, Utah. The lack of salmonflies in the Logan River is the only major difference in aquatic invertebrate assemblages between the two rivers. Transplant experiment In June 2001 a mix of immature Pteronarcys californica and Pteronarcella badia nymphs were put in cages at 3 locations in the Logan River and at a control site in the Blacksmith Fork River. The cages were constructed from PVC pipe with 2 mm mesh screens at the ends of each canister to allow for a continuous flow of water through the tubes. Small stones, sticks and stream conditioned leaves and detritus were added to each tube for habitat and food. The tubes were checked for nymph survival and replenished with detritus bout every 2 to 4 weeks. Over the next 16 months, several of the cages were vandalized and a few of the nymphs died in the cages. At the site near Dewitt Picnic Area, 9 nymphs survived for 13 months and one nymph lived for 15 months. These results suggested that salmonflies could survive in the Logan River if they were reintroduced. Background The salmonflies, Pteronarcys californica and Pteronarcella badia (Plecoptera: Pteronarcyidae) were once abundant in the Logan River in northern Utah. In 1927, the world renowned entomologist James Needham wrote “Pteronarcys californica abounds in the clear waters of Logan River below 6000 feet. It is undoubtedly one of the most important insect species of the stream. Its greatest abundance seems to be in trash piles that gather against the upstream side of the larger rocks in midstream where it finds both food and shelter. Fifty or more well-grown nymphs could be taken on a screen by dislodging a single large stone (Needham, 1927)”. In later pages of this publication he comments as well on the abundance of Pteronarcella badia in the Logan River. Presently, salmonflies are very abundant in the Blacksmith Fork River, the Logan River’s largest tributary stream and can be found in many other streams in northern Utah and southern Idaho, but not in the Logan River. Collection history of salmonflies in the Logan River Salmonfly facts Salmonflies are stoneflies (Insecta: Plecoptera) within the family Pteronarcyidae. They are the biggest bodied stoneflies in North America and are easily distinguished by the location of their abdominal gills. There are 2 genera in Utah and North America; Pteronarcella and Pteronarcys, and 3 species; Pteronarcella badia and Pteronarcys californica and Pteronarcys princeps in Utah and 10 species in North America. Salmonflies are widely distributed in streams of all sizes throughout the western United States (Figure 2). They are most common at elevations less then 8500 feet. Nymphs generally occur under large rocks or in debris piles. They feed on the leaves of riparian vegetation and detritus. They live 3 to 4 years as nymphs. Nymphs emerge as adults in late spring through summer depending primarily on stream temperatures and elevation. Because of their large size and populous synchronous emergence they are loved by both fish and fisherman. They are known to be sensitive to herbicides and are commonly used in chemical toxicity studies. Adults do not seem to disperse far from their point of emergence (Vinson unpublished data). Reintroduction efforts During 2004 a grass-roots groundswell of community support for returning this noble beast to the Logan River began to materialize. In November, this emotional support was translated into a show of action as several dozen members of the Cache Anglers, the northern Utah Trout Unlimited Chapter, collected several thousand salmonfly nymphs from the Blacksmith Fork of the Logan River and released them into the Logan River. Two cages with 10 salmonflies each were placed where the salmonflies were introduced. A second transplant is scheduled to occur 23 April 2005. We will attempt to transplant mature nymphs that will emerge this spring and hopefully mate and lay eggs in the Logan River. We plan to monitor the success of this transplant and continue the transplants over the next 3 years. Pteronarcys californica What happened in the 1960s that eradicated them from the Logan River and why have they not recolonized? • Least likely explanations: • They were never there? Not likely, the list of past collectors is a Who’s Who of Aquatic Entomology • They are still present? Not likely, We have made more then 200 collecting trips over the last 12 years and failed to find a single individual and we can always collect them in the Blacksmith Fork River. • We misidentified them? Not likely, what could a salmonfly be mistaken for? • Populations are declining everywhere? No, they are common throughout the west (Figure 2) and are very abundant in the Blacksmith Fork River, the Logan River’s largest tributary. • More likely explanations: • Broad-scale sagebrush eradication by the U.S. Forest Service in the 1960s? Perhaps, but why have they not returned after 40 years? • Herbicide spraying and ice melting chemicals that are applied along Highway 89? Perhaps, but why would they not still be present in tributary streams, like the Right Hand Fork of the Logan River or Temple Fork? • Any ideas? Pteronarcella badia Pteronarcys californica Pteronarcys californica For project updates check out the BugLab web site: http://www.usu.edu/buglab/projects/project%20Salmonfly.htm