Blue catfish diet study
Blue catfish are an apex predator in the Mississippi River Basin and according to optimum foraging theory, they should adapt to pursue prey that gives the greatest net energetic return. The high densities of invasive Asian carp in the Mississippi River Basin have provided an alternative energy source for adult blue catfish. We are quantifying the presence of bighead carp and silver carp present in the diets of large, adult blue catfish through manual removal "hand scooping" and gastric lavage techniques.
Diet comparison of native piscivores in Pool 19 and Pool 20 - UMR
To assess baseline diet preferences for piscivorous fishes in Pools 19 and 20 in the Mississippi River, we qualitatively and quantitatively desribed their diets. We were assessing the diets in the presence of low density/no yoy Asian carp and using next-generation sequencing to characterize fish diet contents to species when possible.
Evaluating common snapping turtle recreational harvest in Illinois
Common snapping turtles (Chelydra serpentina) inhabit waterways throughout Illinois and are harvested recreationally for sport and consumption. Seasons and bag limits are in place, but additional data are needed to identify management objectives for common snapping turtle harvest in Illinois. We used mark and recapture, size structure, sex ratio, and fecundity data to populate life tables needed to inform better management practices and harvest regulations for common snapping turtles in Illinois.
Research Projects
LAMER AQUATIC ECOLOGY LAB
Advanced Asian carp telemetry in the Upper Illinios River
We are testing out experimental GPS tags on bighead carp, silver carp, and their hybrids in the Upper Illinois River to test their effectiveness and their ability to inform on Asian carp fine-scale movements, areas of aggregration for feeding or spawning, and the extent of their upstream expansion towards the Great Lakes. We have now expanded the research from using only data logging tags to real-time satellite linked tags.
Herpetofauna survey on the Emiquon and Merwin Preserves
Both the biodiversity and productivity of floodplain rivers in the Midwest has declined tremendously since the early 20th century. While the changes in the populations popular species like fish and waterfowl have been marked by scientists and the local communities, the patterns for turtles and amphibians, less appreciated than those species, were not as well documented. As preserves and managed lands have been set aside to try to bring back our natural heritage we have a new opportunity to understand how and where herpetofauna use the floodplain and whether they too can recover some of their former robust populations.
Reproductive Potential of Asian carp in the UMR
Asian carp abundance in the Mississippi River above Lock and Dam 19 is low relative to reaches below the dam. Understanding the reproductive potential (i.e., gonadalsomatic index (GSI) and fecundity) of these low density, poorly understood populations is important to inform Asian carp management in the Upper Mississippi River. We examined and compared GSI, estimated fecundity, and histologically staged eggs of silver carp and bighead carp among pools 17-20 of the Mississippi River.
Age and growth of Bighead and Silver Carp in the UMR
Fish age and growth can be used to infer spawning success, recruitment and population age structure. Lock and Dam 19 on the Mississippi River restricts upstream migration of Asian carp and possibly recruitment dynamics in this emerging population. Pectoral spines, post-cleithra, and vertebrae have been removed from bighead carp and silver carp to quantify age and growth in pools 16-19 on the Mississippi River. Ages and back calculated growth will be used to better understand spawning success, recruitment and population age structure to inform control and containment actions.
Effects of contracted removal of Asian carp in the UMR
Bighead carp and silver carp (Asian carp) populations are increasing in abundance and expanding their upstream range within the Upper Mississippi River (UMR). Limited fish passage at Lock and dam 19 (LD19) has slowed their progression and establishment in UMR reaches above Keokuk, IA. To combat this population expansion and decrease Asian carp densities at the established front (pools 17, 18, and 19), we are using commercial fishers to intensively target Asian carp species for removal at the established front and invasion front (reaches above pool 17), and determining population abundance to evaluate the effects of harvest
Using Asian carp otolith microchemistry to assess natal origin and dam passage at LD19 in UMR
Expansion of Asian carp above LD 19 on the Upper Mississippi River has been impeded by the high head dam at this location, To determine the extent of reproduction and recruitment above LD19, contribution of tributaries and other habitats above and below the dam to the upper UMR populations, we used stable isotope otolith (lapillus) microchemistry on Asian carp from Pools 16-19. Fish isotope ratios (δ18O, δ13C, and 87Sr/86Sr) and elemental ratios (Sr:Ca, Ba:Ca, Mg:Ca) were compared to established water isotope and elemental ratios throughout the basin to understand the spatial and temporal history of each fish.
Native and larval Asian carp characterization in the UMR
Evidence of Asian carp reproduction was detected as early as 2009 in pool 19, and indicates that areas of the UMR above LD19 are capable of providing the hydrological requirements needed for successful Asian carp spawning, egg maturation, and development. A need exists to comprehensively monitor for larval Asian carp in pools 17, 18 and 19 to detect and quantify larval Asian carp establishment in the the established front. Monitoring Asian carp reproduction and the detection of larval Asian carp will be imperative for informing the best management practices in the UMR above LD19.
Otolith microchemistry, age, and growth of YOY Asian carp in the UMR
High densities of young-of-year Asian carp from multiple cohorts were detected in Pool 19 in 2016. Otolith microchemistry, daily age (hatch date), and daily growth from inter-incremental distances will be used to determine where and when they were spawned, where they drifted and settled post spawn, and the degree that environmental variables and where they were spawned influence their growth.
Validation and comparison of Asian carp aging structures
Silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) have invaded most of the Mississippi River and its tributaries. Although fish age is routinely used to inform management decisions, aging structures for bighead and silver carp have not been validated against known-age fish to ensure accuracy and utility. We used known-age fish reared in Chinese aquaculture and collected from the LaGrange Reach of the Illinois River (tracked annually from a strong 2014-year class) to validate aging structures from bighead carp and silver carp. We removed vertebrae, lapillus otoliths, pectoral spines, and postcleithra from each individual.
Asian carp as forage for Pool 19 piscivorous fishes
In 2016, a recruitment event for Asian carp occurred above LD19 providing us an opportunity to see how native predators in this reach used this novel forage base. Our objectives were to determine the importance and size of Asian carp being consumed. Native predators were collected with electrofishing and tandem fyke nets from Pool 19 and we determined that several native predators were consuming Asian carp.
Estimating Silver carp length using pharyngeal arches and chewing pads
Asian carp that are being consumed by native predators are often only identified from their unique chewing pad and pharyngeal teeth structure. We were able to establish a linear relationship between fish length and measurements on these structures and demonstrate that these structures can be used to estimate the length of silver carp being consumed by native predators and provide insight into the size Asian carp that our native predators are able to consume.
Size specific feeding on Asian carp by Largemouth Bass in the IL River
In 2014, a large Asian carp spawning event in the La Grange reach of the Illinois River produced an abundance of age-one silver carp in 2015. This provided the opportunity to investigate their use as forage for native piscivorous fishes and the size structure of fish utilizing this resource. We collected fishes from contiguous backwaters and tributaries on the La Grange Reach of the Illinois River using pulse DC- electrofishing from June through November, 2015. Largemouth bass were the primary predator consuming 1 yr silver carp and were able to consume them up to 40% of their total length.
Fish community composition and structure of UMR in relation to LD19
Although some data on fish communities in Pools 19 and 20 exist, the need exists for a comprehensive survey using standardized methodology to assess the composition and structure of fish communities in this region. We used pulsed-DC electrofishing to duplicate LTRM effort and methodology to establish baseline fish community data and quantify differences between the pools.
Quantification and validation of YOY Asian carp lapillus otoliths
Despite the research and resources dedicated to Asian carp management in the Mississippi River Basin, information on young of year Asian carp is still lacking. Daily incremental growth annuli from otoliths were used to estimate age and birth dates of young of year Asian carp. We collected young of year Asian carp from the La Grange Reach of the Illinois River in August of 2014 and validated daily growth increments with known-age fish reared in Chinese aquaculture.
Juvenile Asian carp forage for native piscivores - IL River.
Large Asian carp spawning events in the Illinois River produce millions of young of year bighead carp and silver carp. We are investigating how native piscivores respond to this excess of forage, which species show a preference for Asian carp, and at what size they are able to escape predation.
Ontogenetic diet shift in Blue Catfish
Blue catfish are dominant predators in the Mississippi River and consume a wide breadth of diet items. We used stable isotope ratios to determine the size at which diet changes occur in blue catfish and to quantify trophic changes occur. Blue catfish were sampled with the help of Catfish Quest and Twisted Cat tournaments throughout the midwest to obtain length, weight, and muscle biopsies needed for stable isotope analysis.
Species composition and structure in Pools 19 and 20 in the UMR
Young of year Asian carp have been detected in Pool 19 as early as 2009 and their densities continue to increase in the Upper Mississippi River. Working with UMESC, USGS we have intensively sampled the large, vegetated impounded areas and contiguous backwaters of pool 19 using single and tandem fykes and mini-fyke trap nets. This intensive sampling was initiated for the detection of YOY Asian carp, but has also been important for documenting the fish communities of these habitats as well.
Composition and structure of Pool 19 backwaters and the detection of YOY Asian carp in pool 19.
Young of year Asian carp have been detected in Pool 19 as early as 2009 and their densities continue to increase in the Upper Mississippi River. Working with UMESC, USGS we have intensively sampled the large, vegetated impounded areas and contiguous backwaters of pool 19 using single and tandem fykes and mini-fyke trap nets. This intensive sampling was initiated for the detection of YOY Asian carp, but has also been important for documenting the fish communities of these habitats as well.
Paddlefish dam passage at LD15 and LD16
Lock and Dams 15 and 16 are not often at open river conditions and the extent they are able to pass native fishes is not known. We are assessing the ability of paddlefish to navigate these two dams/locks. Information gained will serve as a baseline for fish passage a these structures and assess any impacts potential invasive species deterrent systems may have at these locations.