Project Sampling Effeciency Assessment for Silver Carp and Bighead Carp in Nebraska Mid-Order Streams and Rivers

Currently, eDNA is being used to investigate the distribution of invasive carp among lotic systems in Nebraska. However, attempts to verify eDNA results via live-fish collection have seen limited success due in part to limited understanding life-stage specific habitat use within prairie systems and the sampling methods to collect individuals effectively among different habitat types. Therefore, the study objectives of this project are to: 

• Investigate sampling methods (i.e., towed trawls, various net configurations, and different electrofishing methods, etc.) that can effectively sample the invasive carp population
• Devise a sampling protocol for use in prairie systems that can target different life-stages of invasive carp populations. 

Such a protocol can be used to inform information gaps based on desired management objectives including documenting presence, assessing demographic rates, and/or eradication efforts. We will employ multiple gear-types including trawls, nets, and tow-barge electrofishing. Sampling efforts will occur spring, summer, and fall starting in 2023 and continuing into 2024. We will focus sampling efforts in mid-order prairie streams and rivers that are tributaries to the Missouri River and the Platte River in Nebraska. Streams and systems may include the Blue River, Nemaha Rivers, and Papillion Creek, along the Missouri River. Streams and systems may include the Salt Creek, Elkhorn River, Shell Creek, and Loup River along the Platte River. We will use information from eDNA results to direct sampling to locations with both positive and negative results for presence of invasive carp. Lower reaches of these systems may be accessible by boats using traditional sampling gears. We will sample river and stream reaches higher in the watersheds where traditional methods are not easily employed.

Goals

1. Assess the temporal and spatial distribution and conduct an assessment of population characteristics including—but not limited too—relative abundance, size structure, and age structure of Silver Carp and Bighead Carp populations on the Platte River and lower reaches of major tributaries of Platte River,
2. Assess population connectivity between the Platte River and Missouri River, and
3. Assess spawning phenology and recruitment of young-of-year Silver Carp and Bighead Carp within the Platte River and within reaches of major tributaries of the Platte River.