Joshua K. Raabe

• PhD
• Associate Professor of Fisheries and Water Resources at University of Wisconsin–Stevens Point

We developed a spatial capture–recapture model to evaluate survival and activity centres (i.e., mean locations) of tagged individuals detected along a linear array. Our spatially explicit version of the Cormack–Jolly–Seber model, analyzed using a Bayesian framework, correlates movement between periods and can incorporate environmental or other cova...

Despite extensive management and research, populations of American Shad Alosa sapidissima have experienced prolonged declines, and uncertainty about the underlying mechanisms causing these declines remains. In the springs of 2007 through 2010, we used a resistance board weir and PIT technology to capture, tag, and track American Shad in the Little...

Fish, especially migratory species, are assumed to benefit from dam removals that restore connectivity and access to upstream habitat, but few studies have evaluated this assumption. Therefore, we assessed the movement of migratory fishes in the springs of 2008 through 2010 and surveyed available habitat in the Little River, North Carolina, a tribu...

Walleye (Sander vitreus) occur naturally or through extensive introductions in many inland lakes (i.e., non-Laurentian Great Lakes) throughout North Central North America. Persistence of walleye in these systems is influenced by factors including habitat, species interactions, exploitation, and stocking. Managers have expressed concerns about recen...

Nature‐like fishways are engineered to be low maintenance, aesthetically pleasing, and pass a diversity of species. However, evaluations of nature‐like fishways are limited, especially on large rivers and for anadromous species. Therefore, we studied a nature‐like “rock arch rapids” rock ramp fishway constructed in 2012 at the most downstream of th...

Black bullhead Ameiurus melas are an environmentally tolerant fish that are often the target of population‐level management efforts due to overabundance and potential negative influences on sport fishes. Descriptions of black bullhead growth and life history have been limited in part due to challenges in age estimation. Pectoral fin spines have bee...

Previous research indicates that lake sturgeon Acipenser fluvescens recruitment is limited in the Lower Fox River below De Pere Dam. Habitat enhancements in the form of an offshore reef have been proposed to potentially improve the recruitment of lake sturgeon. However, identifying spawning habitats for other species could help to ensure that resto...

Objective Fish movements and distributions throughout an ecosystem are important for understanding ecological interactions, conservation, and management. Coarse woody habitat (CWH) additions are a popular habitat enhancement tool that can influence movements and distributions of fishes; however, behavioral responses in relation to CWH additions are...

Fish behavior after passage or transfer around dams is a critical component in determining whether the goals of these efforts are achieved, but these behaviors are often poorly understood. An elevator was constructed in the lowermost hydroelectric dam on the Menominee River, Wisconsin–Michigan; it is the first elevator specifically designed to capt...

Riparian habitat and groundwater inputs are critical components to maintaining high quality, headwater streams for cold-water species. Brook Trout (Salvelinus fontinalis) feed on both aquatic and terrestrial invertebrates that drift downstream, where availability and importance of such prey potentially varies by habitat type. Our study objectives w...

Brook Trout (Salvelinus fontinalis) are a popular sportfish and the only trout native to Wisconsin streams. They require cold, well oxygenated water and are sensitive to disturbance and changes in water quality. These specific habitat requirements can make managing Brook Trout difficult as anglers’ expectations sometimes clash with biological limit...

Scale and hierarchy have received less attention in aquatic compared to terrestrial systems. Walleye (Sander vitreus) spawning habitat offers an opportunity to investigate scale’s importance. We estimated lake-, transect-, and quadrat-scale influences on nearshore walleye egg deposition in 28 Minnesota lakes from 2016–2018. Random forest models (RF...

Behavioral responses of fishes to littoral zone habitat enhancements are relatively understudied in diverse fish communities but are critical for understanding overall fish community responses. To advance knowledge on effects of coarse woody habitat (CWH) littoral zone enhancements, we initiated a long-term study on Sanford Lake, Vilas County, Wisc...

Natural reproduction of salmonids occurs in many Lake Michigan tributaries, yet little is known about abundance and the potential contribution of wild fish hatching in Wisconsin tributaries. The objectives of our study were to determine if: 1) abundance of wild juvenile salmonids (primarily adfluvial rainbow trout, Oncorhynchus mykiss, referred to...

Brook trout Salvelinus fontinalis populations inhabiting groundwater-fed, headwater streams are sensitive to biotic and abiotic changes caused by anthropogenic actions in their native range but can be very resilient in their introduced range. Brook trout have maintained a self-sustaining population in the Little Plover River, Wisconsin, despite fis...

Evaluation of brook trout diel behaviors (hourly PIT antenna detections) relative to time of year, spawning activity, and environmental conditions in the Little Plover River, Portage County, Wisconsin.

Brook Trout were implanted with radio transmitters to monitor movements and habitat use in the Little Plover River. Preliminary results indicate relatively small home ranges that increased for some individuals during the spawning period, individuals used restored reaches along with an agricultural ditch and small channel in the most upstream reache...

Lake sturgeon Acipenser fulvescens were extirpated from the St. Louis River Estuary (SLRE) by the early 1900’s due to overfishing and habitat degradation. A restoration stocking program began in 1983, and continued almost annually until 2000. Lake sturgeon stocked into the SLRE were primarily obtained from the Wolf River (Lake Winnebago) genetic st...

The Little Plover River in Portage County, Wisconsin, flows through a single culvert at County Highway R. This study evaluated Brook Trout passage success through the culvert between May 2016 and October 2019 using passive integrated transponder (PIT) tags and PIT antennas installed at the culvert.

Dam removals allow fish to access habitats that may provide ecological benefits and risks, but the extent of fish movements through former dam sites has not been thoroughly evaluated for many species. We installed stationary PIT antennas in 2016 and 2017 to evaluate movements and survival of brook trout Salvelinus fontinalis in the West Branch of t...

Brook trout abundance trends relative to environmental conditions.

Brook trout spawning timing and locations were documented via redd surveys in 2017-2019, and compared to discharge and estimated groundwater influx.

Sass GG, Shaw SL, Rooney TP, Rypel AL, Raabe JK, Smith QC, Hrabik TR, Toshner ST. 2019. Coarse woody habitat and glacial lake fisheries in the Midwestern United States: knowns, unknowns, and experiment to advance our knowledge. Lake Reserv Manage. XX:XXX–XXX. Coarse woody habitat (CWH) additions have increased in popularity in glacial lakes (i.e. k...

The Tomorrow River is recognized locally and statewide as a natural resource treasure. Its clear, cold waters support native trout, wildlife, recreational opportunities and regional economic development. Through the years, public and private interests have worked to protect and preserve this riparian gem. Over 70 years ago, the Izaak Walton League...

Habitat is an integral component of lake ecosystems and threatened by anthropogenic alterations. Quantifying habitat is typically done with labor intensive and spatially limited surveys (i.e., transects) or with surveys requiring specialized field equipment combined with computer analyses (i.e., sonar). These approaches are limited to inventorying...

Understanding ecological relationships among fishes and their environments are important for informing management policies. We conducted a statewide assessment of cisco Coregonus artedi in inland lakes of Wisconsin to better understand the status of this pelagic, coldwater forage fish. We then used long-term (2005–2014), standardized walleye Sander...

Addition of trees to the littoral zones of inland lakes is a commonly used management practice aimed to restore fish habitat. However, fishery and aquatic ecosystem responses to this management practice have rarely been evaluated. Removals of coarse woody habitat (CWH) from lakes as a result of lakeshore residential development, physical removal, a...

Update on brook trout movements, survival, and spawning in the Little Plover River. Data analyzed include PIT antenna detections from July 2016 - January 2018 and a redd survey in Fall-Winter 2017.

Addition of trees to the littoral zones of lakes is a commonly used management practice aimed to restore fish habitat. However, fishery and aquatic ecosystem outcomes of this management practice have rarely been evaluated. Removals of coarse woody habitat (CWH) from lakes as a result of lakeshore residential development, physical removal, and lake...

The Little Plover River is a self-sustaining brook trout stream and the focal study system for groundwater issues in central Wisconsin. The Village of Plover is facilitating watershed restoration efforts to increase stream flows. The goals of this study are to evaluate brook trout seasonal habitat use, movements, body condition, and survival using...

Understanding population dynamics among co-occurring fishes is important for informing regional fisheries management policies. We conducted a statewide assessment of cisco Coregonus artedi in inland lakes of Wisconsin to better understand the status of this coldwater forage fish. We then used Wisconsin walleye Sander vitreus data (2005-2014) to tes...

Understanding sampling efficiency and movements of subadult Lake Sturgeon Acipenser fulvescens is necessary to facilitate population rehabilitation and recruitment monitoring in large systems with extensive riverine and lacustrine habitats. We used a variety of sampling methods to capture subadult Lake Sturgeon (i.e., fish between 75 and 130 cm TL...

Walleye (Sander vitreus) populations are cyclic because of biotic and abiotic factors, and wind activity, wave energy, and water levels may be influential given walleye spawn close to shore. We installed an anemometer and tridirectional velocimeter on a spawning reef in Big Crooked Lake, Wisconsin, in 2005 to determine wind–wave relationships and w...

Walleye (Sander vitreus) populations are cyclic because of biotic and abiotic factors, and wind activity, wave energy, and water levels may be influential given walleye spawn close to shore. We installed an anemometer and tridirectional velocimeter on a spawning reef in Big Crooked Lake, Wisconsin, in 2005 to determine wind–wave relationships and w...

Little is known regarding habitat use of sub-adult lake sturgeon in riverine portions of the Lake Winnebago system located in central Wisconsin. Understanding habitat use by sub-adult fish will improve lake sturgeon assessment by allowing biologists to better evaluate recruitment dynamics and identify critical habitat. Characterizing habitat and su...

Three lock and dams (LD) on the Cape Fear River, North Carolina, maintain water levels for municipalities and industry but impede migratory fishes to varying degrees. To improve fish passage, a rock arch rapids fishway was constructed in 2012 at LD-1 (river kilometer (rkm) 97). This is the first implementation of this design for anadromous fishes a...

Large dams on the Yadkin – Pee Dee River Basin in North and South Carolina have greatly reduced the extent of fish migrations and available habitat. Fish passage options are being considered, including capturing anadromous American shad Alosa sapidissima downstream of Blewett Falls Dam (lowermost dam) and transporting some upstream of Blewett Falls...

Migratory fish species are assumed to benefit from dam removals that restore connectivity and access to upstream habitat, but few studies have evaluated this assumption. Therefore, I assessed factors influencing distribution and survival of migratory fishes in the springs of 2007 through 2010 on the Little River, North Carolina, a tributary to the...

Habitat suitability index models for American shad Alosa sapidissima were developed by Stier and Crance in 1985. These models, which were based on a combination of published information and expert opinion, are often used to make decisions about hydropower dam operations and fish passage. The purpose of this study was to develop updated habitat suit...

Advances in telemetry technology, including smaller transmitters and stationary receivers, allow studies to collect a plethora of spatial data on tagged individuals. While computing capabilities and software (e.g., GIS) offer options to analyze spatial data, quantitative models capable of using all data points are lacking. We developed a spatial ca...

Spawning habitat, the cornerstone of self‐sustaining, naturally reproducing walleye Sander vitreus populations, has received limited quantitative research. Our goal was to quantitatively describe the structure and quantity of natural walleye spawning habitat and evaluate potential selection of habitat in Big Crooked Lake, Wisconsin. In 2004 and 200...

Habitat is a fundamental cornerstone of fish populations and our ability to manage habitat is predicated on understanding relations between fish population dynamics and habitat quantity and quality. However, in few areas of fisheries overall do we lack science-based management as badly as we do in managing habitat. In north temperate lakes, poor re...

Declines in anadromous American shad Alosa sapidissima populations along the Atlantic Coast have led to a variety of restoration efforts, including dam removal and fish passage. Since dam removal is an emerging science, questions remain regarding the use of restored habitat by American shad and whether increased migrations influence their survival....

Habitat is a fundamental cornerstone of all fish populations and is broadly defined herein as those physical and chemical features of aquatic systems that affect survival, growth, reproduc-tion, and recruitment. Simply stated, it is where fish live and the conditions that occur there. Interestingly, despite widespread interest in managing habitats...

Coastwide declines in anadromous American shad Alosa sapidissima populations have led to a variety of restoration efforts, including dam removal and fish passage. We commenced a study in 2007 on the Little River, North Carolina, a tributary to the Neuse River with three dam removals since 1998. The relatively small size of this river (mean March-Ma...

Critical to the conservation and management of sustainable populations of walleye, Sander vitreus, throughout North America is the need to understand what comprises and compromises high quality spawning habitat. In particular, questions remain regarding the actual selection of spawning habitat by walleye, how physical characteristics and functional...