Invasive Fishes: Ecology and Management (hosted by AFS)

Contributed Paper Session
ROOM: Atlantis, Grand Ballroom 3

8:00AM Incorporating Basic and Applied Approaches to Evaluate the Effects of Invasive Asian Carp on Native Fishes: A Necessary First Step for Integrated Pest Management
Quinton Phelps, Sara Tripp, Kyle Bales, Daniel James, Robert A. Hrabik, Dave Herzog
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. 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.
8:20AM Asian Carp Early Life History and Reproduction in the Upper Mississippi River
James Lamer, Charmayne Anderson, Jesse Williams, Boone La Hood, Tyler Thomsen, Allison Lenaerts, Kevin Irons, Brent Knights, Michael Weber, Clay Pierce, Gregory Whitledge, Kyle Mosel, Ann Runstrom, Nicholas Bloomfield
Bighead Carp and Silver Carp reproduction in the Mississippi River system has been evident since the 1990’s and despite the wealth of research devoted to their life history, dynamics contributing to their early life history and spawning behavior are still not well understood. The complementary design and synthesis of independent agency research and monitoring provides a comprehensive insight into Asian carp production and early life history. The multi-agency collaborative assessment provides location of spawning activity (egg trawls, YOY otolith microchemistry, telemetry), frequency of spawns (egg trawls, larval light trapping, otolith microstructure, histological evidence, spawning patches and year class strength observed through contracted removal), and magnitude of individual spawns (larval light trapping, YOY sampling, year class strength). These collective efforts identified tributary contributions to production, identified up to 7-8 unique spawning events in 2016, contributed to identification of hydrological triggers correlated with spawning behavior, and identified factors contributing to YOY success. This research and collaboration demonstrates the value of multi-agency partnerships to address complex issues in invasion biology.
8:40AM Seasonal Water Area Uses of Asian Carp in the Upper Illinois River Waterway Using Acoustic Telemetry.
Jehnsen Lebsock
Asian Carp are a highly invasive species introduced into the Mississippi River System in the mid 1970’s and now, due to expanding populations, are a pervasive threat to invading the Great Lakes. The Dresden Island, Marseilles, and Starved Rock Asian Carp populations in the upper Illinois River waterway (leading edge) pose the greatest risk to the Great Lakes. Therefore, understanding their habitat use and behavior in this region are important to enhance removal efforts and restrict further expansion. The objectives of our study were to determine habitat preferences, and identify areas of concentration of silver carp, bighead carp, and grass carp at their leading-edge population using acoustic telemetry. Asian carp species were tracked from March – October 2018 using a mobile Vemco VR-100 receiver at pre-defined grid points (0.54 km apart) within the three pools. Detections from 125 tagged Asian carp have been used to identify seasonal water use associations (85 in Dresden Island, 15 in Marseilles, and 33 in Starved Rock). Our tracking efforts have detailed habitat selectivity for the Dresden Island Pool, and Starved Rock pool, as well as seasonal movements between spring, summer, and fall. Continued tracking will reinforce this data for all three pools.
9:00AM Population Demographics of Bigheaded Carp and Multiple Commercial Bycatch Species in Pools 16-19 of the Mississippi River
Zachary Witzel, Dominique Turney, Tyler Thomsen, Madeline Tomczak, Cassidy Miles, Jehnsen Lebsock, Kevin Irons, James T. Lamer
Silver carp and bighead carp (bigheaded carp) have spread throughout the Mississippi River basin since their introduction in the 1970’s. Highly adaptable life history traits have contributed to their invasiveness and their ability to negatively affect native fish populations and ecosystems. Bigheaded carp can drive density dependent reductions in their body condition and that of other native species. Detection of a deviation from body condition baselines in bigheaded carp and native species over time can be used as a surrogate to evaluate tools used to reduce bigheaded carp populations. Therefore, the objectives of our study are to track body condition of bigheaded carp and multiple commercial bycatch species over time in pools 16-19 in the Upper Mississippi River. Gill nets were deployed to capture silver carp, bighead carp, and associated bycatch during the 2015- 2019 field seasons. Length and weight were recorded from all fishes and relative weight determined using standard weight equations for each species. Bigheaded carp body condition has remained steady indicating densities are remaining low. Trends in body condition and population demographic data can be used to evaluate the effectiveness of harvest, help managers populate spatially explicit models and prompt increased strategic removal efforts.
9:20AM Size Selectivity of Gill Nets Used to Target Silver and Bighead Carp in the Upper Mississippi
Zachary Witzel, Kevin Irons, James T. Lamer
Bigheaded carp (bighead carp and silver carp) are highly invasive fishes in the Mississippi River System and can be detrimental to native fishes and ecosystems. To limit their impact and further expansion, fishermen have been contracted through state and federal agencies to remove bigheaded carp using predominantly gill nets. Mesh size of entanglement gears determines the size structure of fishes able to be captured. To increase efficiency and effectiveness of bigheaded carp harvest and minimize the capture of bycatch, it is important to understand the relationship of gill net mesh size with the size structure of persistent populations. Therefore, the objective of our study is to determine the size of bigheaded carp and commonly encountered bycatch that are effectively caught in different sized gill nets based on their size. Gill nets were used in pools 16 through 20 on the Mississippi River to capture silver carp and bighead carp. For every 25.4 mm increase in gill net mesh, it was determined that there is a 200 mm increase in the highest retained bigheaded carp body size. With this information managers will be able to more efficiently target bigheaded carp if knowledge of population size structure is available.
09:40AM Break
1:10PM Otolith Microstructure and Trace Elemental Analyses of Age-0 Silver Carp in the Upper Mississippi River
Jesse Williams, Gregory Whitledge, Brent Knights, Nicholas Bloomfield, James Lamer
Silver Carp (Hypophthalmichthys molitrix) may spawn multiple times and come from multiple nurseries in a given river reach. In 2016, a high-magnitude spawning event of Silver Carp occurred near the invasion front in the Upper Mississippi River (UMR). Understanding reproduction, growth and nursery habitats can be beneficial to management. Our objectives were to determine (1) hatch dates and back-calculated growth rates from otolith microstructure and (2) nursery locations of young-of-year (YOY) Silver Carp from otolith microchemistry. We collected 12,208 YOY Silver Carp from Pools 18-19 of the UMR (16–231mm) between July 2016 to October 2016. Lapilli and asteriscii otoliths were removed, polished, and photographed. Lapilli otolith daily increments were used to calculate hatch dates and incremental distance was measured to determine daily growth. Nursery origins of YOY were determined from lapillus otolith (Sr: Ca and Ba: Ca ratios) and asteriscus otolith (stable isotope δ18O). Ages ranged from 17–112 days with corresponding hatch dates between May 22–August 14, 2016. Nursery locations were assigned to the main channel above LD19, one of several large tributaries, or small tributaries above LD19. This study demonstrates multiple spawning events and nursery sources that might contribute to recruitment.
1:30PM Variability in Silver Carp Population Demographics in the Kansas River
Jake Werner, Marty J. Hamel
Silver Carp are distributed throughout much of the lower Missouri River basin and the presence of anthropogenic barriers across the landscape is the primary mechanism slowing range expansion. The Kansas River is a large tributary system that drains most of northern Kansas. Silver carp are restricted to the lower reach of the Kansas River (~83 rkm) because of multiple barriers. A semi-impassable barriers (i.e. water diversion weir) offers an opportunity to analyze how barriers can influence silver carp population demographics across the landscape. Adult silver carp were collected from above and below the weir using a suite of gears and otoliths were extracted for age and growth and microchemistry analyses. Silver carp were scarce above the weir but attained a larger length at age similar to lesser abundant populations along the invasion front. Microchemistry analysis indicated that both transient and local fish were found in the Kansas River, and the natal origins were indicative of multiple spawning sites throughout a variety of connected river ecosystems. Juvenile silver carp have not been documented above the weir indicating that reproduction is limited in this reach.
1:50PM Population Characteristics of Invasive Common Carp in a Large Coastal Lake
Jesse R. Fischer, April D. Lamb
Lake Mattamuskeet is 16,000-hectare shallow lake that comprises the majority of the Mattamuskeet National Wildlife Refuge, serving as a critical overwintering habitat for a diversity of waterfowl and shorebird species in the Atlantic Flyway. Abrupt losses of submerged and emergent aquatic vegetation and declines in water quality and clarity throughout the ecosystem warranted greater research into the potential mechanisms responsible for this shift. Common Carp (Cyprinus carpio) are one of the most widely introduced and ecologically disruptive freshwater fish species and was previously targeted for removal in the Lake Mattamuskeet during the 1940-1950s. Therefore, our objective was to describe the population dynamics of Common Carp in Lake Mattamuskeet for developing age-structured population models. Dorsal-fin spines were used estimate age and measure growth using two readers. A total of 347 spines were collected from fish sampled during standardized boat electrofishing surveys in fall of 2016-2018. Overall, Common Carp exhibited truncated age structure (i.e., age-1 to age-8, fast growth, moderately high mortality (i.e., 48.2%, SE=0.0004), and consistent recruitment. Our results provide critical life history information of the invasive Common Carp population in Lake Mattamuskeet needed to evaluate simulated exploitation levels necessary to cause recruitment failure and minimize future carp reduction efforts long-term.
2:10PM Response of Invasive Brown Trout to Sustained Mechanical Removal in Bright Angel Creek, a Grand Canyon Tributary, with an Evaluation of Movement in the Main Channel Colorado River
Robert C. Schelly, Brian D. Healy, Charles B. Yackulic, Michael J. Dodrill, Clay B. Nelson, Emily C. Omana Smith, Mark M. McKinstry, Sarah K. Haas, Phaedra Budy
Salmonids are widely introduced globally. Beginning in the 1920’s, trout were introduced into spring-fed Colorado River tributaries in Grand Canyon, where they remained initially restricted owing to the high turbidity, prodigious seasonal floods, and warm summer temperatures of the unregulated Colorado River. Following completion of Glen Canyon Dam in 1963, hypolimnetic releases have rendered the main channel suitable for trout, and the upstream Lees Ferry reach is now managed as a Rainbow Trout sport-fishery. Our study concerns Brown Trout, a high-risk threat to native fishes, and the focus of intensive mechanical removal efforts across 20 km of Bright Angel Creek for the last seven winters to benefit native fish recovery. We report 80% reductions in trout numbers in Bright Angel Creek in the context of annually variable recruitment potentially influenced by density-dependence and hydrology. Additionally, in light of recent (2014-16) increases in Brown Trout captures at Lees Ferry, we examine >20 years of PIT-tag recapture data and two years of telemetry data from 39 sonic tagged Brown Trout to assess movement throughout Grand Canyon. Our results contextualize Brown Trout movement and recruitment patterns across irregular hydrologic regimes, and provide an extended case-study for predicting responses to nonnative fish removal.
2:30PM Impacts of Temperature and Non-Native Brown Trout on Rio Grande Cutthroat Trout Production
Lauren Flynn, Brock Huntsman, Colleen Caldwell, Abigail Lynch
Native Cutthroat Trout (Oncorhynchus clarkii spp.) populations in the western U.S. have declined due to habitat loss, climate change, and invasion of nonnative trout, but mechanisms to explain the decline varies by subspecies and geography. We used a production framework to investigate the potential interactions among temperature and Brown Trout (Salmo trutta) invasion on Rio Grande Cutthroat Trout (O. c. virginalis, RGCT) in the southern Rocky Mountains. We gathered biomass, growth, and temperature data from four sympatric and four allopatric RGCT populations in New Mexico headwater streams (August 2017-August 2018) using three-pass depletion and mark-recapture techniques. Based on non-overlapping 95% confidence intervals, allopatric populations of RGCT had consistently higher abundance, biomass, and secondary production rates (g/m2.yr-1) than sympatric RGCT populations, indicating that sympatric RGCT populations have a low capacity to withstand invasion. Though the streams clearly separated into cold and warm temperature treatments, our results lacked evidence for a strong temperature effect on production (overlapping 95% CIs). While these results are consistent with similar studies in the Northern and Middle Rocky Mountains, they offer fresh insights to the unique environmental conditions of headwater streams in the Southwest and justify shrewd conservation and management strategies.
2:50PM Refreshment Break
3:20PM Evaluating Population Status and Potential Ecological Impacts of Invasive Catfish in the Chesapeake Bay
Morgan Corey, Bruce Vogt
Invasive blue catfish and flathead catfish represent a growing threat to native ecosystems in the Chesapeake Bay. Predation by blue catfish is of concern particularly for economically-valuable managed fisheries like blue crab and the threatened alosine complex of shad and herring. Since their introduction in the 1970’s, blue catfish have rapidly expanded in distribution among Chesapeake Bay tributaries given their high tolerance for changing conditions, apparent in years with higher-than-average precipitation levels like 2018. In order to track the potential impact of invasive catfish on native Chesapeake resources, we synthesized monitoring data to evaluate the bay-wide and tributary-specific population status in each major system (James, Rappahanock, Choptank, Nanticoke, Potomac, York, Patuxent, and Susquehanna Rivers) of the Chesapeake. In data-rich tributaries, we evaluated relationships between abundance of blue catfish and historical abundance of representative native populations using correlation analysis. We then assessed the utility of updating several modeling approaches to assess tributary-specific ecological interactions, including salinity drivers and diet data from gut content analysis. While the Chesapeake Bay currently lacks a coordinated management strategy for addressing the issue, this effort can help to resolve uncertainty about the magnitude of ecological impact by invasive catfish.
3:40PM Sublethal Effects of Salinity and Temperature on Invasive Blue Catfish
Vaskar Nepal KC, Mary C. Fabrizio
Blue Catfish (Ictalurus furcatus), recognized as a freshwater species, is an invasive fish of increasing management concern in the Chesapeake Bay region. The impacts of this species on estuarine resources in the Bay likely depend on its responses to temperature and salinity regimes. In particular, the performance of Blue Catfish at increased, but sublethal salinities has not been quantified. In a laboratory setting, we exposed subadult Blue Catfish to salinities of 1, 4, 7 and 10‰ and temperatures of 12 or 22°C for 16 weeks. Although growth was observed at all treatment levels, growth was consistently greater at 22°C compared with 12°C, and was maximized at 4‰ and minimized at 10‰. In addition, body condition was greater at 22°C across all salinities except 10‰, where body condition decreased significantly. These results were accompanied by a significantly lower food consumption rate at 10‰ compared with other salinities and suggest that Blue Catfish may not be able to thrive at salinities >10‰. However, Chesapeake Bay habitats where salinity is <10‰ are exploitable to invasive Blue Catfish for elongated periods of time, and may provide refugia for Blue Catfish that occupy or colonize high salinity waters.
4:00PM Evaluating Suppression Options for an Introduced Cyprinid in a Montane Lake Using a Population Model
Troy Smith, Brad Liermann, Lisa Eby
The introduction of novel organisms can alter predation, food webs, and species interactions on naive ecosystems. Illegal introductions of redside shiners (Richardsonius balteatus) to high mountain lakes can result in declines of the quality of salmonid fisheries. Redside shiners were illegally introduced to Green Canyon Lake, MT in the 1980s. We demonstrated substantial diet overlap of shiners with westslope cutthroat trout (Oncorhynchus lewisi) along with a shift in zooplankton community composition to smaller species. In 2017 and 2018, we set minnow traps to estimate redside shiner demographic rates. We used a Leslie Matrix model to evaluate two hypothetical suppression actions: a single piscicide application and maintained densities of a biotic control (tiger trout, Salmo trutta x Salvelinus fontinailis). Modeling a 95% population reduction with piscicide application, the shiner population returned to 90% of carrying capacity in 26 years under our strongest compensatory response scenario. By linking energetics simulation results of tiger trout consumption into the population model, we expect a density of approximately 1000 tiger trout would be required to extirpate the shiner population within six years. Our results suggest that redside shiners have the capacity for rapid population growth requiring suppression actions to be robust and persistent.
4:20PM Project Update on Establishing a Nonnative Predator Research and Pilot Fish Removal Program on the Stanislaus River, California
Matthew Peterson, Jason Guignard, Andrea Fuller, Doug Demko
Federal legislation (Water Infrastructure Improvements for the Nation Act, 2016) requires the Oakdale and South San Joaquin Irrigation Districts and NOAA Fisheries to jointly establish a multi-year research program in the Stanislaus River to investigate whether predator removals are an effective strategy to improve the survival of juvenile salmonids. Initial project goals included efforts to: (1) gather data on the abundance, composition, and distribution of both native and nonnative fish predators in the Stanislaus River; (2) gather age composition and diet information from fish predators; and, (3) implement and assess removals of piscivorous fishes using a Before-After-Control-Impact study design. The sampling design allows for information to be gathered on both temporal and spatial aspects of predation in the Stanislaus River with randomly selected sampling locations revisited multiple times. Data will be analyzed using a robust design framework to account for the ability of tagged predators to move into and out of the sampled locations (i.e., an open population). Data from the study can provide insight on how predation risk (e.g., the number of Chinook salmon consumed by predators) may change through time and space as well as how predator populations may change throughout the study period.



Contributed Paper Session
Location: Atlantis Hotel Date: October 3, 2019 Time: 8:00 am - 5:00 pm