Multiscale Prediction of Whirling Disease Risk in the Blackfoot River Basin, Montana: a Useful Consideration for Restoration Prioritization?

Abstract

Habitat restoration for inland trout (family Salmonidae) is common across western North America, but planners rarely consider disease risk when prioritizing restoration sites. Whirling disease is a parasitic infection caused by the invasive myxosporean parasite Myxobolus cerebralis and has been implicated in declines of wild trout populations across western North America. For planners to consider disease, disease risk needs to be predictable across the landscape and influence restoration outcomes. We collated the history of whirling disease infection severity scores on the MacConnell-Baldwin scale from sentinel cage studies for hatchery Rainbow Trout Oncorhynchus mykiss in the Blackfoot River basin from 1998 to 2009. At these same sites, we performed reach-scale geomorphic assessments, derived landscape variables from GIS data layers, and assembled fish composition data. We examined relationships between the severity of infection and several landscape-scale and reach-scale variables for 13 basin-fed streams in the Blackfoot River basin of west-central Montana using classification and regression tree analyses. In our data set, valley slope and forest cover were the best predictors of fine sediment. Both spring creeks and gently sloping alluvial basin-fed tributaries to the Blackfoot River basin with higher proportions of fine sediment (particle size < 0.85 mm) were associated with a high severity ( grade 3) of infection. Additionally, we explored differences in trout species composition (i.e., susceptible versus resistant species) before and after the whirling disease enzootic using seven basin-fed streams and two spring creeks. We did not detect trout community shifts from susceptible to disease-resistant salmonids in basin-fed disease-positive streams. However, spring creeks showed a negative trend in disease-susceptible salmonids after the whirling disease enzootic. Disease risk appears to be predictable across the landscape and may limit possible restoration outcomes by influencing species composition in spring creeks.

A Scoping Review on GIS Technologies Applied to Farmed Fish Health Management

“…[7]. However, it should be noted that over time, an interest in investigating other GIS applications has emerged, such as estimating the spatial distribution of ecosystem services in wide transitional areas of high ecological value [68], water/land use risk assessments at multiple spatial scales [20], and prioritising habitat restoration efforts for inland wild trout [69]. Moreover, GIS data collection allowed for model elaboration in order to have the efficient use of natural resources (e.g., optimal temperature range) targeted at higher-risk animals and geographic areas for early disease detection, which represented a reliable bioinformatic platform for future refinement [50].…”

Effect of substrate on the proliferation of Myxobolus cerebralis in the mitochondrial lineages of the Tubifex tubifex host

“…Here, we investigated how two substrates influence infection and proliferation of M. cerebralis in the different lineages of the Tt host. Previous studies have implicated sediment type in predisposing the Tt host to WD (Arndt et al 2002 ; Blazer et al 2003 ; Gilbert and Granath 2003 ; Krueger et al 2006 ; Eby et al 2015 ). Our earlier work showed that mud facilitated M. cerebralis development in pure clonal lines of TAM producing mt 16S rDNA lineage III from non-TAM-producing (resistant) to TAM-producing (susceptible) phenotypes (Baxa et al 2006 , 2008 ).…”

“…As these studies have shown, the mt 16S rDNA lineages are divergent in susceptibility to infection with M. cerebralis and parasite production relative to geographic locality, dose of parasite exposure, genotype composition, and habitat type (Stevens et al 2001 ; Beauchamp et al 2002 ; Blazer et al 2003 ; Dubey and Caldwell 2004 ; Kerans et al 2004 ; Rasmussen et al 2008 ; Hallett et al 2009 ). Furthermore, differences in parasite proliferation in the Tt host have been attributed to contributions of key environmental factors such as water temperature (El-Matbouli et al 1999c ; Kerans and Zale 2002 ; Blazer et al 2003 ; Kerans et al 2005 ), confounding environmental features (Kaeser et al 2006 ), and complex habitat components (Eby et al 2015 ). Altered habitats have also been reported to influence WD propagation (Thompson et al 2002 ; Thompson 2011 ; Granath 2014 ; Richey et al 2018 ).…”

The Intestinal Parasites of an Assemblage of Stream Fishes in Central Utah

“…Recent studies of fish parasites in western North American streams and rivers have focused on metozoan parasites in salmonids. Concern about whirling disease caused by Myxobolus cerebralis has prompted a significant effort directed toward detection and management of this protozoan (Kaeser et al 2006, Koel et al 2006, Eby et al 2015, Fetherman et al 2015, Murcia et al 2015, Nehring et al 2015. Whereas, the effort to curb whirling disease is an important management goal for salmonid sport fishes, the consequence has been that studies on internal nonprotozoan parasites in stream fishes of the western United States have been neglected.…”