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ANSI Asian Carp Research

Kaskaskia, Sam Parr, and Ridge Lake Biological Stations

Catch rates and cost effectiveness of entrapment gears for Asian carp: a comparison of pound nets, hoop nets, and fyke nets in backwater lakes of the Illinois River.

North American Journal of fisheries management. 35:1219-1225.

Scott F. Collins, Steven E. Butler, Matthew J. Diana, and David H. Wahl

Participating Agencies:  INHS

We compared three entrapment gears to determine which method was the most effective for capturing invasive Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix in terms of numbers of fish captured and labor invested. Gears were deployed concurrently in two backwater lakes of the Illinois River during the summers of 2012–2014. Overall, the nightly catch rates of all fishes, Bighead Carp, and Silver Carp were one to three orders of magnitude greater in pound nets than in either fyke nets or hoop nets. Pound nets collected larger Bighead Carp than hoop nets and fyke nets. Hoop nets were ineffective at catching Asian carp in backwater lakes. Estimation of the effort required to deploy, maintain, and remove each gear type indicated that pound nets were the most cost-effective gear due to their high catch rates of Asian carp relative to the labor hours invested to collect the catch. Pound nets appear to be an effective means of removing Asian carp in backwater lake habitats of the Illinois River.


Evaluation of Gear Efficiency and Asian Carp Detectability

Steven E. Butler, Matthew J. Diana, Scott F. Collins, David H. Wahl (Illinois Natural History Survey), Robert E. Colombo (Eastern Illinois University)

Participating Agencies:  INHS (lead), Eastern Illinois University (field and lab support)

Multi-agency sampling and removal efforts, using a variety of sampling gears, are currently ongoing in the Illinois River and the CAWS to monitor and control populations of Asian carp.  Different sampling gears may vary widely in their ability to capture fish in proportion to their abundance, and may select for different sizes of fish.  Evaluating the relative ability of traditional and alternative sampling gears to capture both juvenile and adult Asian carp will help improve the efficiency of monitoring programs and allow managers to more effectively assess Asian carp relative abundance.  Data gathered from gear evaluations can also be used to calculate detection probabilities for Asian carp, which would allow for determination of appropriate levels of sampling effort and help improve the design of existing monitoring regimes.  Results of this study will help improve Asian carp monitoring and control efforts in the Illinois River and the CAWS, and will contribute to a better understanding of the biology of these invasive species in North America.

Project Highlights: 

  • Pulsed-DC electrofishing was the most effective gear for capturing Silver Carp, whereas hoop nets were the most effective gear for capturing Bighead Carp.  Hybrid Asian carp were vulnerable to both electrofishing and hoop nets.
  • Asian carp were most abundant in the LaGrange and Peoria Pools; abundance declined at upstream sites, and no Asian carp were observed in the CAWS.
  • No age-0 Asian carp were observed in 2013.  Possible age-1 Asian carp (< 500 mm) were most abundant in the Peoria Pool, but were relatively scarce elsewhere, suggesting populations consisting primarily of larger, older fish.
  • Tributary sites were sampled with pulsed-DC electrofishing gear in the Spoon, Sangamon, Mackinaw, and Kankakee Rivers during 2013.  No Asian carp were observed in the Kankakee, whereas 513 Asian carp were captured from the other three tributaries. 
  • Detection probabilities for Asian carp were lower at upstream sites than at downstream sites.  Given the lowest estimates of detection probability for sites where Asian carp were captured, a minimum of 17 pulsed-DC electrofishing transects (15-minute duration) are necessary to achieve a 95 percent probability of capturing at least one Silver Carp, whereas a minimum of 42 hoop net-nights would be required to achieve this same cumulative detection probability for Bighead Carp.  Even higher sampling efforts are likely necessary to achieve these same levels of confidence at sites with lower Asian carp abundance.


Larval Fish / Productivity Monitoring in the Illinois Waterway

Steven E. Butler, Matthew J. Diana, Scott F. Collins, David H. Wahl (Illinois Natural History Survey), Robert E. Colombo (Eastern Illinois University)

Participating Agencies:  INHS (lead), Eastern Illinois University (field and lab support)

Factors affecting the early life stages of fish strongly influence recruitment to adult populations.  An evaluation of Asian carp reproduction and recruitment in different sections of the Illinois Waterway is needed to better understand Asian carp population dynamics in this system and potentially develop management strategies targeting early life stages.  Larval and juvenile Asian carp have previously been collected in the Alton, LaGrange and Peoria Pools of the Illinois River, but the potential for Asian carp reproduction in upstream reaches or in tributaries of the Illinois Waterway is unknown.  Additionally, reproduction and recruitment are known to be highly variable among years in the lower Illinois River, with consistently poor recruitment observed in recent years.  Information on the spatial and temporal distribution of Asian carp eggs and larvae will help to identify adult spawning areas, determine reproductive cues, and characterize relationships between environmental variables and survival of young Asian carp.

Asian carp are filter-feeding planktivores that have the ability to deplete plankton densities and alter zooplankton community composition.  Because Asian carp require sufficient food resources to optimize feeding and sustain their growth, they may associate with areas of higher productivity.  Phytoplankton and zooplankton densities are expected to vary considerably both across the longitudinal gradient of a large river and among habitats within river segments.  Therefore, identifying patterns in nutrient concentrations, phytoplankton densities, and zooplankton abundance may indicate locations where Asian carp are most likely to be located.  Examining relationships between the abundance of Asian carp, other planktivorous fishes, and productivity variables will provide information on Asian carp foraging ecology and will help focus sampling and removal efforts.  This information will also be useful for examining relationships among nutrients, phytoplankton, and zooplankton abundance in a large river system.

Project Highlights:

  • Over 500 larval fish samples were collected from 13 sites across the length of the Illinois Waterway during May – October, 2013, capturing over 27,000 larval fish, including 344 larval Asian carp.
  • Larval Asian carp were only collected in the Peoria Pool in May, and the LaGrange Pool in June.  No Asian carp larvae were observed from the upper Illinois Waterway or from Illinois River tributaries.
  • Phosphorus concentrations are highest in the Des Plaines River and the lower CAWS.  Chlorophyll a concentrations do not appear to be correlated with phosphorus concentrations, and are highest in the lower Illinois River.
  • Zooplankton densities in the CAWS appear to be similar to or higher than those observed in the Illinois River, suggesting that the CAWS is capable of providing sufficient food resources for Asian carp.


Unconventional Gear Development

Steven E. Butler, Matthew J. Diana, Scott F. Collins, David H. Wahl (Illinois Natural History Survey)

Participating Agencies: INHS (lead), IDNR (project support)

Traditional sampling gears vary widely in their ability to capture Asian carp, and many are far more successful at capturing non-target species.  Additionally, the ability of some of these gears to capture Asian carp in the conditions found in the CAWS is questionable.  A working group composed of fisheries scientists and commercial fishers was convened in 2011 to discuss development of gears specifically targeting Asian carp in areas of low density and in the deep-draft channels of the CAWS.  This committee decided to pursue evaluation of three new sampling gears: large (2 m diameter; 6.4 cm square mesh) hoop nets, surface-to-bottom gill nets (91.4 m long x 8.5 m tied down to 6.1 m depth; 6.4, 7.6, 8.9, and 10.2 cm mesh panels), and Great Lakes style trap (pound) nets (100 m lead, 6.1 x 3.0 x 3.0 m pot, 7.6-9.1 m wings, 3.8-7.6 cm mesh).  Evaluating these and other gears/methods alongside traditional sampling gears (see Evaluation of Gear Efficiency Plan) is necessary for understanding the potential utility of these new techniques as tools for monitoring and controlling Asian carp in the upper Illinois/Des Plaines River and the CAWS.

Project Highlights:

  • Large (2 m) hoop nets captured fewer fish of all taxa, and fewer Asian carp than standard (1.2 m diameter) hoop nets.
  • Surface-to-bottom gill nets captured more Asian carp than traditional gill nets during 4-hour sets.
  • Driving fish into surface-to-bottom gill nets with pulsed-DC electrofishing gear captured more Asian carp than drives using traditional pounding methods or control sets.
  • No Asian carp were captured in pound nets at Lake Calumet in 2013.  Pound nets were effective at capturing large numbers of fish, including a high proportion of Asian carp, at the Materials Service Pit (Marseilles Pool) and at Lilly Lake (LaGrange Pool).


Impacts of Invasive Asian Carps on Native Food Webs

Jonathan A. Freedman, Steven E. Butler, & David H. Wahl (INHS)

Participating Agencies: INHS (lead), Illinois-Indiana Seas Grant (funding)

Bighead Carp and Silver Carp are invasive throughout much of the Mississippi River system, and are threatening to invade the Great Lakes. Despite comprising the majority of the fish biomass in the lower Illinois River, their effects on native species and food webs are not well understood. We used stable isotope analysis of carbon (δ 13C) and nitrogen (δ 15N) to examine the food webs of high and low Asian Carp density sections of the Illinois River, and compared these with historic collections from before the Asian Carp invasion of the late 1990s.  We found that fish in the high density lower river fed at lower trophic levels compared to the low density site or historic samples, suggesting that Asian Carps are dominating the food web by consuming the majority of available zooplankton. Carbon isotopes at the low density
site were compressed, suggesting that there may be a nutrient bottleneck hindering upstream dispersal of Asian Carp in the Illinois River.  Stable isotope signatures of Asian Carp were most similar to Bluegill, Emerald Shiner, and Gizzard Shad, suggesting high trophic overlap with these facultative planktivores that pick zooplankton from the water column. There was less overlap and apparent competition between Asian Carps and filter feeding planktivores Bigmouth Buffalo and Paddlefish.  The potential effects on Great Lakes ecosystems if Asian Carps become established are unknown, but could prove catastrophic. Our project shows how Asian Carps impact food webs in the Illinois River, and thus reveals potential effects on food webs in the Great Lakes.


Understanding the Effects of Asian Carp on Native Fishes

Jonathan Freedman, Kirsten Nelson, Steven Butler, Matthew Diana, and David Wahl (INHS)

A summary of field, stable isotope, and mesocosm research conducted through the Kaskaskia, and Sam Parr Biological Stations.

Full Article

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