Kelly Turek, graduate student, will defend her master's degree thesis, "Influence of Non-Native Trout on Native Non-Game Fish in Nebraska Headwater Streams," at 1 p.m., March 19 in the Hardin Hall auditorium (room 107).
Abstract:
Introduced, non-native trout may have detrimental competitive or predatory interactions with native fishes. However, few studies have experimentally examined interactions between introduced trout and native non-game species. The objectives of this study were to determine 1) if non-native rainbow trout Oncorhynchus mykiss influence survival, behavior, movement, or distribution of native longnose dace Rhinichthys cataractae under laboratory conditions, 2) if non-native rainbow trout influence survival of native longnose dace under in-situ conditions using in-stream enclosures, and 3) if non-native brown trout Salmo trutta or rainbow trout influence native populations or communities under natural conditions.
Rainbow trout preyed on longnose dace at low rates in both laboratory and in-stream enclosure experiments suggesting that if rainbow trout and longnose dace overlap in microhabitat use, some predation is likely to occur. Therefore, it is not recommended that non-native trout be stocked in streams containing at-risk species. Greater non-native trout abundances resulted in greater distinction in native community composition and structure between sites with trout compared to sites without trout suggesting there may be increased risk to native communities in sites with high abundances of trout. Therefore, caution should be taken in stocking non-native trout even in streams with common and abundant native species.