The Long-term Illinois River fish population monitoring program, Annual Report

Report issued on: March 2003Annual ReportINHS Technical Report prepared for Illinois Department of Natural Resource

Agate Fossil Beds National Monument Fish Inventory

The Niobrara River flows through Agate Fossil Beds National Monument (AGFO) maintaining about 18-km of riverine habitat. The lack of large-scale human alterations like impoundment and channelization to the Niobrara River within AGFO make this stretch of river an ideal location to support native fish communities. However, concern for native fishes in the Niobrara River in and around AGFO has grown because non-native brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss have been actively stocked in the region. Other species like largemouth bass Micropterus salmoides, bluegill Lepomis macrochirus, and northern pike Esox lucius may have also established populations from stocking activities above or below the AGFO property

Do Nitrogen and Phosphorus Influence Channel Catfish Growth in a Great Plains River?

Evaluating abiotic environmental factors that influence growth of sportfish is key to understanding population dynamics and making appropriate management decisions. This is especially true in river systems where primary and secondary productivity can vary across temporal and spatial scales. In this study, we assessed fish responses to ambient nutrient levels (total nitrogen and total phosphorus) using growth rates determined from age-1 Channel Catfish, Ictalurus punctatus, in Platte River, Nebraska. Water quality and growth data were collected from sites across the central and lower Platte River from 2007 to 2013. We analyzed Platte River water quality data to find yearly average levels of total nitrogen and phosphorus in the system. Results show a significant difference in growth rates and nutrients levels across Platte River segments, however nutrient levels did not help explain the differences in growth. For example, the mean growth rate across years was not significant between central and lower river segments (p-value = 0.202), but the mean total nitrogen and total phosphorus levels were significantly greater in the lower river segment across all years (p = 0.004 for nitrogen and p = 2.028-6 for phosphorus). While this study lacks evidence for a clear correlation between nutrient levels and Channel Catfish growth future investigations could help clarify the short-term and long-term impacts of eutrophication of rivers such as the Platte River that run through agricultural and urban landscpaes

River-Wide Habitat Availability for Fish Habitat Guilds: Implications for In-Stream Flow Protection

The variation in river discharge alters habitat heterogeneity with implications for the distribution of fish species with different habitat requirements. Assessments of habitat availability following changes in river discharge are difficult to apply at broad spatial scales and with relevance to multiple species. We used a MesoHABSIM modeling approach to quantify river-wide changes in habitat availability for five fish habitat guilds under three river discharge levels along the Niobrara River, NE, USA.We used a time-series of river discharge (1958–2010) to create uniform continuous under-threshold habitat duration curves that identified habitat conditions that may result in periods of stress for fish communities along the Niobrara River. Habitat availability for each fish habitat guild was dependent on river discharge and location along the river. Habitat availability for fish habitat guilds ranged from 5% to 49% of the total channel area suggesting habitat availability may, at times, be limited. We provide river discharge guidelines for bioperiods that limit the frequency and duration of stressful habitat conditions. Understanding interactions between river discharge and habitat availability through time and at river-wide scales may aid in managing for ecological integrity by including protection of river discharge variability to support multiple fish habitat guilds

Assessment of a channel catfish population in a large open river system

Estimates of dynamic rate functions for riverine channel catfish, Ictalurus punctatus (Rafinesque), populations are limited. The open nature and inherent difficulty in sampling riverine environments and the propensity for dispersal of channel catfish impede estimation of population variables. However, contemporary population models (i.e. robust design models) can incorporate the open nature of these systems. The purpose of this study was to determine channel catfish population abundance, survival and size structure and to characterize growth in the lower Platte River, Nebraska, USA. Annual survival estimates of adult channel catfish were 13%–49%, and channel catfish abundance estimates ranged from 8,281 to 24,261 fish within a 10-km sampling reach. Channel catfish were predominantly (90%

Fish community response to in-channel woody debris in a channelized river system

Additions of large wood (LW) have become a go-to technique for recovering altered river ecosystems. However, successful applications of this technique are generally limited to unchannelized rivers and headwater streams. Channelization of rivers, that is, engineering river channels to reduce recruitment and retention of in-channel structure, may, by definition, limit success of this restoration technique. Moreover, sufficient time has passed (a century or more) since initial channelization of many large rivers that portions of the fish community associated with LW may have become extirpated. Thus, the maxim that LW leads to a positive fish community response may not hold true. We examined fish community associations in habitats with and without LW in the channelized Missouri River to gain an understanding of the role of LW in large, channelized rivers. There were some differences between habitats with wood present compared to those without, but the differences were not evident once year, season and channel modifications intended to create aquatic habitat were taken into account. We assert that careful planning is necessary to ensure that additions of LW in channelized rivers are made to appropriate locations such that it will be retained in-channel for use as fish habitat and that LW-associated species are found in the system

Habitat associations of shovelnose sturgeon \u3ci\u3eScaphirhynchus platorynchus\u3c/i\u3e (Rafinesque, 1820) in the lower Platte River, Nebraska

Human induced alterations of river systems are ubiquitous throughout the world. Alterations have reduced riverine habitat and negatively affected riverine species; therefore, it is crucial to understand what habitats are important to riverine fish at multiple scales. Most research has focused around microhabitats (i.e., depth) with little effort on how the reach scale habitat (i.e., geomorphic landscape) influences riverine fish abundance. We examined habitat associations of shovelnose sturgeon sampled with two gears (trotlines and trammel nets) at multiple spatial scales in the lower Platte River, NE, a system that has not been overtly altered in physical description. At a microhabitat scale, shovelnose sturgeon abundance was influenced by velocities and temperatures within the lower Platte River. The influence of velocity was contradictory between gears suggesting that gear limitations may have been present. Shovelnose sturgeon abundance increased in close proximity to a tributary interaction with the lower Platte River in both gears. Portions of the river with a relatively medium valley width, low-medium sinuosity, and wide channel had the lowest shovelnose sturgeon abundance for both gears. Our results provide insight at multiple habitat scales on the landscape that may help managers and policy makers develop sound approaches to protecting and mitigating habitat for shovelnose sturgeon and other riverine species