Sara J. Tripp

Incorporating basic and applied approaches to evaluate the effects of invasive Asian Carp on native fishes: A necessary first step for integrated pest management

Numerous studies throughout North America allege deleterious associations among invasive Asian Carp and native fishes; however, no empirical evidence on a system-wide scale exists. We used Mississippi River Basin fish community data collected by the Long Term Resource Monitoring program and the Missouri Department of Conservation to evaluate possible interaction between Asian Carp and native fishes. Results from two decades of long-term monitoring throughout much of the Mississippi River suggest that Silver Carp relative abundance has increased while relative abundance (Bigmouth Buffalo [F 3, 8240 = 6.44, P<0.01] and Gizzard Shad [F 3, 8240 = 31.04, P<0.01]) and condition (Bigmouth Buffalo [slope = -0.11; t = -1.71; P = 0.1014] and Gizzard Shad [slope = -0.39; t = -3.02; P = 0.0073]) of native planktivores have declined. Floodplain lake qualitative evaluations yielded similar results; floodplain lake fish communities were likely altered (i.e., reductions in native species) by Silver Carp. Furthermore, laboratory experiments corroborated field evidence; Silver Carp negatively influence native planktivores through competition for prey (all comparisons, P > 0.05). To this end, this study provides evidence that Silver Carp are likely adversely influencing native fishes; however, mere presence of Silver Carp in the system does not induce deleterious effects on native fishes. To the best of our knowledge, this evaluation is the first to describe the effects of Asian Carp throughout the Mississippi River Basin and could be used to reduce the effects of Asian Carp on native biota through an integrated pest management program as suggested by congressional policy. Despite the simplicity of the data analyzed and approach used, this study provides a framework for beginning to identify the interactions of invasive fish pests on native fishes (i.e., necessary first step of integrated pest management). However, knowledge gaps remain. We suggest future efforts should conduct more in depth analyses (i.e., multivariate statistical approaches) that investigate the influence on all native species.

Mississippi River Basin Paddlefish Population Dynamics: Implications for the Management of a Highly Migratory Species

Management of migratory fishes is a difficult task for fishery managers because fish cross jurisdictional boundaries and encounter differing regulations. States within the Mississippi River basin have differing commercial and recreational regulations for riverine Paddlefish Polyodon spathula populations, and the current population dynamics have not been evaluated on a system-wide basis. The objective of this study was to simulate the current reproductive potential of the population using various harvest scenarios. At the current exploitation rate of all locations pooled (u = 14.8%), the population may experience recruitment overfishing at a 610 mm minimum length limit and has the potential to experience recruitment overfishing at a 710 mm length limit (u = ∼20%). Any added stressors (e.g., Asian carp) may cause further mortality; thus, adopting a precautionary approach is necessary to maintain sustainable Paddlefish fisheries. At an 810 mm length limit, the population would not realistically experience re...

Quantitative Evaluation of Paddlefish Sport Fisheries in Missouri’s Large Reservoirs: Implications for the Management of Trophy Sport Fisheries

AbstractLake of the Ozarks, Harry S. Truman Reservoir, and Table Rock Lake in Missouri contain important recreational trophy Paddlefish fisheries. These three reservoirs have been created by damming major rivers. Because of river modifications, Paddlefish natural reproduction is thought to be limited, and subsequently, populations have been maintained through supplementation and harvest regulations. However, these fisheries have not been thoroughly assessed and the applicability of management actions (e.g., supplementation and minimum length limits) has not been fully evaluated. Population simulations indicated changes in the amount of trophy sized fish and broodstock remaining of each population were similar, with larger minimum length limits resulting in a greater proportion of mature and trophy sized individuals. However, the number of Paddlefish that could be harvested at Harry S. Truman Reservoir and Lake of the Ozarks was much greater than at Table Rock Lake. These disparities are likely attributed ...