Report on the Short-Term Scavenging of Decomposing Native and Non-Native Trout in Appalachian Streams

Trout fishing is one of the primary recreational activities in the southern Appalachians, with large amounts of fish stocked on a regular basis. However, very little is known regarding the fate of hatchery reared carcasses not captured by anglers, representing a likely important ecological resource to local communities. We tested the efficacy of underwater video to characterize short term decomposition and consumption by aquatic scavengers of native brook and non-native rainbow trout, Salvelinus fontinalis and Oncorhychus mykiss. This study took place on the Cherokee Qualla Boundary in North Carolina, a location with one of the highest riverine stocked trout densities in the eastern United States. During May 2017, 10 waterproof cameras were deployed for 1-hour intervals on each carcass twice daily for a period of 5 days. We observed that 75.3% of recorded video contained river chub, Nocomis micropogon, with only 24.7% visited by crayfish, with a maximum of 9 and a mean of 1.93 for N. micropogon. Half of the carcasses were removed within 2 days. Based on natural history evidence and some trail cameras, we believe that otters were removing carcasses. Otters showed no preference for either trout species. Underwater video allowed us to characterize initial decomposition within stream diurnal scavengers in a short period using a visual, non-destructive low-cost method. Future studies should monitor large mammalian scavengers to further elucidate the role of fish stocking on aquatic communities.

Scavenging Behavior of the Aquatic Eastern Hellbender Salamander (Cryptobranchus Alleganiensis) in North Carolina

Vertebrates may scavenge, or utilize carrion resources more than has been widely assumed (Devault et al. 2003). While documentation of scavengers in terrestrial and marine systems has received increased attention (Beasley et al. 2015; Davenport et al. 2016), little is known regarding scavengers in freshwater stream systems. Dominant fully aquatic salamanders are important foragers in these systems and may rival the biomass of predatory fish species (Davic and Welsh 2004). One fully aquatic salamander in Appalachian streams, the eastern hellbender (Cryptobranchus alleganiensis), occurs in NC streams which receive potentially large seasonal influxes of hatchery reared trout (NCWRC 2017). Moreover, few reports exist in the published literature on the food preferences of eastern hellbender salamanders. While hellbender diet is comprised of 90% crayfish based on stomach content analysis (Peterson et al. 1989), a small portion of their diet is thought to include fish or fish bait (Nickerson and Mays 1973). Barring a few anecdotal reports from fisherman, little is known regarding scavenging by hellbenders in NC.

The effects of riparian disturbance on the condition and summer diets of age-0 brook trout (Salvelinus fontinalis) in three central Appalachian streams

Forested headwater streams are dependent on their riparian zones for many critical goods and services. It is assumed that riparian disturbance affects stream food webs, but for some ecologically and economically important taxa like brook trout (Salvelinus fontinalis), little research has been performed. This study found that intense but spatially limited riparian disturbance resulted in significant but context-dependent changes in the diets and condition of age-0 brook trout in three central Appalachian streams. Dietary shifts in two of the streams appeared to enable age-0 brook trout to maintain or increase condition following riparian tree removal. A significant relationship between fish condition and the importance of Ephemeroptera as prey was observed. The lack of dietary shift to energetically important ephemeropterans coincided with decreased fish condition within one stream previously identified to be mildly impacted by acid precipitation. The context within which riparian disturbance occurs plays an important role in determining the overall impact to age-0 brook trout and should be an important consideration in future regulatory and management decisions.

Tracking the downstream impacts of inadequate sanitation in central Appalachia

Poor sanitation in rural infrastructure is often associated with high levels of fecal contamination in adjacent surface waters, which presents a community health risk. Although microbial source tracking techniques have been widely applied to identify primary remediation needs in urban and/or recreational waters, use of human-specific markers has been more limited in rural watersheds. This study quantified the human source tracking marker Bacteroides-HF183, along with more general fecal indicators (i.e. culturable Escherichia coli and a molecular Enterococcus marker), in two Appalachian streams above and below known discharges of untreated household waste. Although E. coli and Enterococcus were consistently recovered in samples collected from both streams, Bacteroides-HF183 was only detected sporadically in one stream. Multiple linear regression analysis demonstrated a positive correlation between the concentration of E. coli and the proximity and number of known waste discharge points upstream; this correlation was not significant with respect to Bacteroides-HF183, likely due to the low number of quantifiable samples. These findings suggest that, while the application of more advanced source targeting strategies can be useful in confirming the influence of substandard sanitation on surface waters to justify infrastructure improvements, they may be of limited use without concurrent traditional monitoring targets and on-the-ground sanitation surveys.