Date of Graduation

Fall 2009


Master of Science in Biology



Committee Chair

John Havel


The rusty crayfish (Orconectes rusticus) is a highly invasive and damaging species that has established high population densities in many North American lakes and rivers. Rusty crayfish are native to the Ohio River drainage but have been spreading to surrounding temperate lakes for the last 40+ years. Recently, rusty crayfish were discovered in Missouri bait shops, but at present no established populations in Missouri lakes have been reported. The purpose of the current study was to assess the risk of colonization by rusty crayfish and other non-native crayfish into a lake with high fishing activity (Truman Reservoir). In order to determine the risk of invasion, I conducted a 2-part survey during summer-fall 2007 to determine crayfish species composition and the likelihood of crayfish invasion via bait-bucket dumping. In order to determine the current crayfish composition of the reservoir, I sampled a variety of habitats in ten regions of the northern half of Truman Reservoir using baited traps. I found crayfish at four of the 44 sites sampled: the northern crayfish (Orconectes virilis) and the White River crayfish (Procambarus acutus), a species not native to this reservoir. I used interviews of 162 local anglers to quantify the frequency of bait-bucket dumping. This survey revealed a high incidence of bait-bucket dumping and a general unawareness of invasive crayfish species.


angler survey, biological invasions, nonindigenous species, invasive species, Truman Reservoir

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