Common Carp Management Plan for the Rice Creek Watershed District, Minnesota

ABSTRACT This document describes the Common Carp Management Plan for the Rice Creek Watershed District, Minnesota

COMMON CARP MANAGEMENT PLAN December 2018

Rice Creek Watershed District Common Carp Management Plan

Matt Kocian Lake and Stream Specialist Rice Creek Watershed District 4325 Pheasant Ridge Dr. NE, Suite 611 Blaine, MN 55449‐4539 Voice: 763.398.3075 Fax: 763.398.3088 [email protected]

Cover photos

Above: Young‐of‐the‐year common carp captured in trap nets in Rice Lake, Anoka County, MN

Below: Adult common carp harvested with box nets in Long Lake, Ramsey County, MN

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Contents Executive Summary ...... 3 Introduction ...... 4 Carp Management Goals ...... 5 Carp Management Tools ...... 6 Monitoring and Modelling ...... 8 Inducing or Increasing Adult Mortality ...... 12 Suppressing Recruitment ...... 15 Adaptive Management Approach ...... 18 System Plans ...... 20 Literature Cited ...... 21

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Executive Summary

This document will describe a plan for common carp management for the Rice Creek Watershed District in Minnesota, USA. The report is organized into two main components: 1) an overview of common carp ecology and available management tools, and 2) specific system management plans. Both components are subject to change as new data and research become available. In this context, “systems” are defined as geographic areas that encompass an individual carp populations, including adult and juvenile seasonal habitats. Specific plans will be updated at individually defined intervals.

Common carp are ubiquitous within the Rice Creek Watershed. Although natural resources managers have long known that carp have a negative impact on lake ecology and water quality, recent research has shed light on the magnitude and mechanisms of their impact. Additionally, new management tools have been developed and tested by the University of Minnesota and their many partners. With this information and promising new tools, common carp management has the potential to drastically improve ecological function and water quality in many lakes around the Rice Creek Watershed and Minnesota.

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Introduction

Common carp (Cyprinus carpio), indigenous to Eastern Europe and Western Asia, were first introduced in the United States in the late 1800’s. The introduction was purposeful, carried‐out by the U.S. Commission of Fish and Fisheries, and indented to promote a fishery for sport and food sources. Since introduction, common carp spread quickly across the United States; most states now have reproducing populations. In Minnesota, common carp are widespread and often found in high abundance. Several other species of carp have also been introduced to the United States and Minnesota – for example, silver carp (Hypopthalmichthys molitrix), known for their jumping ability, and bighead carp (Hypopthalmichthys nobilis). For the purposes of this report, the term “carp” will be used to describe common carp (Cyprinus carpio) (Figure 1).

Figure 1. Common carp (Cyprinus carpio). Image credit: Joseph Tomelleri

In North America, common carp negatively impact native ecosystems, fish populations, and water quality by their feeding and spawning behavior (Parkos III, Santucci et al. 2003, Bajer, Sullivan et al. 2009, Weber and Brown 2009). When carp are abundant, the abundance and distribution of native plants declines, nutrients (phosphorus) and chlorophyll‐a (algae) increase, and water clarity decreases. Carp root in lake sediments, destroying native vegetation that would otherwise stabilize lake sediments. Their rooting behavior also disturbs and entrains lake sediments, which carries phosphorus into the water column. Carp ingest invertebrates that live in sediment and excrete dissolved nutrients into the water column. By these mechanisms, carp behavior directly increases phosphorus loading, which fuels algae blooms. Carp also indirectly degrade water quality and are often referred to as “ecosystem engineers”. Ecosystem services that would mitigate phosphorus loading and dampen algae blooms are

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also lost; aquatic plants cannot stabilize sediments or take‐up and store phosphorus, and zooplankton populations decline due to loss of refuge provided by plants.

Most research on carp and their negative impacts on lake ecosystems focuses on adult fish. However recent research indicates that juvenile carp have similar negative effects on nutrient concentrations, water clarity, and algae blooms (Weber and Brown 2015). This bolsters that argument for managing common carp on a system‐wide scale – including spawning and juvenile nursery areas ‐ instead of on a lake‐by‐lake basis.

The negative effects of carp on lakes are not uniform. Impacts are greater in shallow lakes with more littoral habitat, where ecological mechanisms play a large role in lake nutrient dynamics. Also, the density of carp plays a key role in the magnitude of their impact. The approximate threshold at which the negative effects are observed is 100 kg/ha (Bajer, Sullivan et al. 2009, Bajer, Headrick et al. 2014). When carp density is below this threshold, negative effects may be minor. At higher densities, carp can have a significant negative effect.

Although specific details about the impacts of carp on water quality have only recently been identified (e.g. Bajer 2009), lake managers have long understood the general link between carp and poor water quality. Carp management has occurred in Minnesota dating back to the mid‐1900’s. Early management tools included the use of non‐selective fish toxins (rotenone) and winter seining. For example, the Minnesota Department of Natural Resources (MNDNR) has used trap‐nets and seines to remove carp and bullhead in the 1950’s. Based on MNDNR reports, these efforts were met with mixed success, and any positive outcomes were temporary. In recent years, several carp management efforts have found success in reducing carp biomass below the ecological damage threshold and improving water quality (Schrage and Downing 2004). In the Rice Creek Watershed, significant improvements in water clarity have been achieved in Howard (02‐0016) and Silver (62‐0083) Lakes by common carp management.

Carp Management Goals

Given the currently available management tools, it is not economically feasible to eradicate common carp from the Rice Creek Watershed. Further, it may not generally feasible, regardless of effort. Thus, the management goal for common carp is to attain and maintain a population density below which they

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negatively affect water quality. This threshold is approximately 100 kg/ha (90 lbs/acre) (Bajer, Sullivan et al. 2009, Bajer, Headrick et al. 2014). The actual threshold may vary among systems, and positive outcomes may be achieved at slightly higher or lower carp densities. The variability of density threshold among systems highlights the importance of monitoring and adaptive management.

Management of common carp alone will not always fully restore lake water clarity (Weber and Brown 2009, Bajer and Sorensen 2015). For those degraded systems with high carp density, reducing that density below the ecological impact threshold will be a necessary component of lake restoration. However, other phosphorus loading sources must be evaluated and potentially mitigated.

Carp Management Tools

The Integrated Pest Management (IPM) approach will provide the overall framework for managing common carp in the RCWD. The IPM approach follows a stepwise approach, generally including identification of the problem, prevention and exclusion, monitoring, and multiple‐tactic control methods. In recent years, this approach has been adapted for common carp by Dr. Peter Sorensen and Dr. Prezemek Bajer at the University of Minnesota. The adapted approach focuses on employing an array of methods that target ecological or biological weakness in common carp, implemented in an economically and ecologically sustainable manner. The management tools identified in this plan fit within the IPM framework, and are evaluated for use based on, among other things, overall effectiveness and economic sustainability. As carp management tool are evaluated for individual systems, the Rice Creek Watershed District will consider effectiveness, efficiency, and reliability.

Before identifying specific management tools, it is useful to consider the population dynamics of the common carp (Figure 2).

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Figure 2. Conceptual population dynamics model for common carp. Courtesy of Dr. Przemek Bajer.

Beginning in about 2007, research conducted by the University of Minnesota has identified several new and innovative carp management tools. These tools were developed after research discovered new information of carp behavior and migratory patterns.

The first of these new tools is based on the tendency for carp to school (or “shoal”) during winter months. While carp are often broadly distributed around lakes, rivers, and wetlands during summer months, they tend to congregate into tight groups during winter. Although this behavior is common, the timing and location of the shoaling is not predictable. Additionally, multiple shoals may exist within a single waterbody, and individual shoals may contain varying proportions of the total population. The exact reason for this behavior is poorly understood. Knowledge of this behavior creates an opportunity for removal by a commercial fisherman via under‐the‐ice seining.

Secondly, the University of Minnesota discovered that carp populations are sustained by their ability to seasonally invade and reproduce in shallow lakes and wetlands prone to winter hypoxia (Bajer and

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Sorensen 2009, Banet 2016). The general pattern was described thusly: Adult carp spend winters in lakes that are sufficiently deep to maintain adequate dissolved oxygen concentrations. In the spring, they migrate to connected shallow lakes or wetlands and spawn. If the shallow lakes or wetlands do not winterkill, native centrarchids (sunfish) prey on carp eggs, thus limiting or eliminating recruitment. If, however, these shallow lakes or wetlands experience winter hypoxia and native fish winterkill, the carp eggs survive and hatch. Juvenile carp will live in these shallow “nursery” systems between 0 and 2 years, after which they will migrate to join the adult population in the connected deep lakes. The dispersal rates of the juvenile carp from the nursery system to the deep system tends to be low, and annual mortality rates in the nursery system were high (Lechelt, Kocian et al. 2017). This general pattern has been observed in many systems.

The Integrated Pest Management framework shown in Figure 2 identifies several key components for successful implementation of a carp management program:

 Monitoring and Modelling  Tracking Carp Movement (immigration, emigration, and seasonal migration)  Inducing or Increasing Adult Mortality; and  Suppressing Recruitment

A general overview of each program component is provided here. These management tools are not exclusive; in many systems, a combination of tools will be required to meet goals. The use of each management tool may vary, based on program or system limitations and opportunities. Most importantly, management tools should be selected based on their applicability for each system, as directed by data and the most recent scientific evidence. These sections will be updated as new research and management information becomes available. Successful implementation of carp management will utilize tools that are effective, efficient, and reliable.

Monitoring and Modelling Estimating the Abundance of Adult Carp

The abundance of adult carp may be estimated by several methods. One of the most commonly used methods for estimating fish abundance is the “mark‐recapture” method. This method works in two parts. First, adult carp are captured, marked (typically with a fin clip), and released. Although there is

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no minimum number of adult carp that need be marked during the first stage, the accuracy of the population estimate increases with the number of fish marked. Second, another, typically larger number of adult carp are captured. The total carp population is estimated by applying an equation to the proportion of marked vs unmarked adult carp in the second capture event. This method is more time intensive, and thus relatively more expensive than other methods. However, assuming an appropriate number of carp were captured during the mark and recapture, this method produces more accurate population estimates.

Electrofishing is a second means for estimating adult carp abundance. In this method, an electrofishing boat is used to capture adult carp. The catch per unit effort (CPUE) provides an estimate of the population via a regression formula (Bajer and Sorensen 2012).

Although both methods are standard in the fisheries management field, error introduced by the methods and by geographic heterogeneity of adult carp populations limits estimate precision. Ideally, both methods should be used to maximize accuracy and precision.

Detecting and Estimating the Abundance of Juvenile Carp

Perhaps the most important step in developing a carp management plan for a system is identifying recruitment hotspots. Detecting the presence and estimating abundance of juvenile carp in shallow lakes and wetlands suggests the need for recruitment suppression. This is done with electrofishing or with standard trap nets. If juvenile carp are not detected in connected shallow lakes and wetlands, and juvenile carp are not captured in other parts of the system, management will focus on adult mortality, and not recruitment suppression.

Tracking Carp Movement (immigration, emigration, and seasonal migration)

Carp movement may be tracked actively with radio‐tags, or passively with PIT (passive integrated transponders) tags and antennas.

Radio‐tags may be implanted in adult carp body cavities. Each radio‐tag broadcasts a unique radio‐ frequency, which may be located using a radio receiver tuned to each frequency. Standard radio telemetry techniques are used to locate tagged carp. This type of active tracking is useful for locating

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groups of adult carp under the ice for seining. It’s also useful when searching for carp during spawning periods to identify spawning locations. Radio tags are not inexpensive (~$200/per) and require skill and experience for successful implantation. Tracking with a radio receiver requires some training and practice but is not complex.

PIT tags and antennas are useful for passively tracking migration patterns. PIT tags are implanted into carp body cavities. Each PIT tag is encoded with a unique identification number. PIT antennas log the date and time of PIT tags as they pass the antenna. PIT tags are relatively cheap (~$2/per) and easy to implant. Alternately, PIT antenna installation requires specific expertise. PIT antennas have relatively high power demands; they may be powered by batteries and solar arrays, but AC power is preferred.

Lake Monitoring Data

There are several key pieces of in‐lake monitoring data that inform a successful carp management program, including, but limited to, dissolved oxygen concentrations, nutrient concentrations and seasonal dynamics, aquatic plant distribution and density, and bathymetry. Many studies have documented carps’ negative impact on nutrient concentrations and water clarity. Thus, these data are potential indicators of carp density changes following management.

Winter dissolved oxygen data are useful for identifying unstable shallow carp nurseries. Shallow lakes and wetlands that are connected to deep systems may serve as carp recruitment areas, IF those systems periodically experience winter hypoxia.

Nutrient concentrations provide an overall indication of potential carp impact. Oligotrophic and mesotrophic systems are likely not negatively impacted by high carp densities. Seasonal nutrient dynamics may provide clues about the density of a carp infestation (Bajer and Sorensen 2015).

Aquatic plant surveys also provide an indication of potential carp impact. Systems with diverse and well‐ distributed aquatic plant assemblages are likely not impacted by high carp densities. Likewise, lakes with littoral areas that are devoid of aquatic plants may have high carp density. As with nutrients and clarity, changes in aquatic plant assemblage, distribution, and density may be indicative of changing carp density.

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Modelling Carp Population Dynamics

Models developed by the University of Minnesota have been used to approximate carp populations under varying management scenarios (Bajer, Parker et al. 2015). The model is informed by adult carp population size, migration patterns, seasonal hypoxia data, recruitment patterns, and population age dynamics – i.e. the monitoring program components identified here. Figure 3 provides an example model output with different management scenarios involved removal of adult carp. As with all models, the results are approximations, and should be used for broad planning purposes.

The model requires several key pieces of information. First, it is necessary to identify recruitment success. Identifying recruitment hotspots and estimating recruitment abundance is key. Second, understanding recruitment frequency is necessary. This is done by aging adults and developing an age‐ frequency dataset (Figure 4). Last, a good understanding of natural mortality rates for juvenile and adult carp are needed.

Figure 3. Carp population model output example based on adult removal scenarios. The y‐axis shows carp biomass in kg/ha and the x‐axis shows years. The colored lines show individual model runs.

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Figure 4 Carp age‐frequency graph example.

Inducing or Increasing Adult Mortality Increasing adult mortality is achieved by removing carp from the system, or by inducing death of the carp in situ. Various methods may be employed to increase adult mortality, singularly or in combination. Methods include:

Removing Adult Carp

Several methods are available for removing adult carp. The methods may be used individually or in combination, based on the availability of resources, carp location and behavior, weather, ice conditions, and commercial fisherman cooperation.

Winter seining is conducted when carp are aggregated, typically in cold weather months (i.e. November – April). As of 2018, winter seining has been conducted only by licensed commercial fisherman in Minnesota. Carp aggregations are located using radio‐tags, and the location of the aggregation is provided to the commercial fisherman. When successful, this method for carp removal is very economical; large numbers of carp may be removed at relatively low cost. Depending on the

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arrangement with the commercial fisherman, the cost per carp removed ranges from $0 to approximately $2.50 (up to approx. $0.50 per pound). Unfortunately, this method is susceptible to failure, typically as seines snag debris and sediment on the bottom of lakes. Overall, RCWD deems this method economical, but not reliable.

Box netting is conducted during summer months. Box nets are baited with cracked corn – a food source favored by common carp, but not by native fish. The box net is square or rectangular, with a bottom and sides, but no top. The net is baited with corn for several days to “train” carp to aggregate inside the net when the sides are down. The box net is triggered while carp are aggregated inside, and side panels are rapidly raised. This method for carp removal is not susceptible to failure. However, it is less economical than winter seining. Depending on the labor source for baiting and pulling the nets, and the means for disposal of the carp, the approximate cost per carp removed ranges from $2‐4.50 (approx. $0.38 ‐ $0.90 per pound). Overall, RCWD deems this method reliable, but less economical. This tool may become more economical as it is refined and scaled‐up.

Netting in conjunction with an Electrical Guidance System (EGS) may provide an economical way to remove large numbers of migrating carp. The EGS system is used to guide migrating carp into box or trap nets, relying the carps’ avoidance of the electrical current in the EGS. This technology is currently (2018/2019) being tested by the RCWD and the University of Minnesota. Initial results indicate high efficacy, as 75% of a migrating carp population was successfully guided into traps (Bajer, Claus et al. 2018). Figure 5 provides an idea of the site layout.

A potential add‐on technology to improve efficiency of this management tool is the Whooshh system (https://www.whooshh.com). This technology, currently being tested by the University of Minnesota, may provide semi‐autonomous removal of common carp during migration via a “volitional entry system”. For more information, see https://www.maisrc.umn.edu/stream‐barriers , or contact the Minnesota Aquatic Invasive Species Research Center.

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Figure 5 Aerial photo of EGS and trap installation on Rice Creek. Modified from Bajer et al 2018.

Introducing Lake‐wide Toxin (rotenone)

Rotenone is a commonly used fish toxin (piscicide) derived from plants. Rotenone is not a species‐ specific piscicide; as a lake management tool, it is generally used to kill all fish in a waterbody. MNDNR has used rotenone in this way to “reclaim” many shallow lakes with high carp and bullhead densities. Rotenone is typically applied directly by boat or helicopter. This management tool was used on Howard Lake in the Rice Creek Watershed. The MNDNR has expressed concerns about using or permitting the use of rotenone in future carp management projects due to public perceptions of risk to humans and non‐target wildlife.

Introducing Toxins with Bait

This tool is an emerging technology currently under development at the University of Minnesota. Like box netting, this tool relies upon the carps’ affinity for cracked corn. Once carp are “trained” to visit an area to consume the corn, a fish toxin is introduced. The U of M has tested this method using the toxin Antimycin‐A. Testing conducted in ponds in 2018 found that the toxin did not leach into the surrounding water and was not consumed by non‐target species. Lethal doses were delivered to

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common carp. Testing continues; it may be many years before this method is approved by regulatory agencies for field use.

Pathogens

This tool is an emerging technology currently under development at the University of Minnesota. The method would involve deployment of species‐specific viruses or bacteria to induce carp mortality. Testing continues in in 2019; it would likely be many years before this method is approved by regulatory agencies for field use.

Suppressing Recruitment Blocking Migration of Adult Carp

Blocking the migration of adult carp as they move deep lakes to shallow spawning habitat can reduce spawning success. Barriers are placed between deep winter lakes, and shallow spring spawning areas. Several barrier types are available for blocking migrating carp. The simplest barriers are physical structures, often made of steel, aluminum, or plastic. Figure 6 shows a typical physical barrier. This example has sliding gates. When closed, the barrier should block most sized juvenile and all adult carp under most (if not all) flow scenarios. Gates may be opened to allow native fish passage, or to pass debris during late‐winter flood‐prone periods. Physical barriers are simple, relatively inexpensive, and potentially very effective. However, they may require frequent maintenance if floating debris is present and may increase flood risk and damage. Also, they block watercraft travel.

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Figure 6. Example of physical fish barrier with operational gates. Rondeau Lake, MN.

Electric barriers are also utilized to block migrating adult carp. High‐voltage electric barriers are designed to induce galvanotaxis (uncontrollable muscle stimulation) in fish, effectively stunning fish as they migrate upstream. A fish migrating upstream into a high‐voltage barrier is stunned and carried back downstream until outside the electric field. Based on this mode of operation, high‐voltage barriers are only effective for blocking upstream migration. Low‐voltage barriers, also known as “electric guidance systems” (EGS), may be used to block migration, or guide fish into traps for removal. Low‐ voltage barriers do not induce galvanotaxis, but rely on carps’ negative affinity for electrical stimuli. Recent tests in the RCWD indicate high effectiveness for blocking (90%+) and guidance (75%) of upstream migrating carp (Bajer, Claus et al. 2018). Many successful examples of high‐voltage barrier installations are available in Minnesota and elsewhere. Low‐voltage electric barriers (EGS systems) are less common, notwithstanding the example in RCWD.

Acoustic barriers are a new technology currently under development at the University of Minnesota and elsewhere. Acoustic barriers rely on carps’ negative affinity for sound stimuli. Few examples of long‐ term field tests or installations are available.

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Blocking Migration of Juvenile Carp

In some systems, natural mortality rates of juvenile carp are high in nursery areas. In these systems, the longer juvenile carp remain in nursery areas, the lower the recruitment rate will be. As with adult carp, there are several options for blocking migration: physical, electrical, and acoustic barriers.

Few (if any) examples exist of physical barriers for juvenile carp. The issues that make physical barriers problematic for adult carp – specifically, their propensity to trap debris and create flooding hazards – are even greater for juvenile barriers, as the gap size between bars must decrease.

High‐voltage barriers would work on juveniles as with adults. The RCWD has deployed a low‐voltage barrier to suppress downstream migration. Effectiveness data are not available as of 2018.

Acoustic bubble barriers – relying on sound generated by a high‐pressure bubble curtain – were found to block the passage of 75‐80% of juvenile common carp in a laboratory setting (Zielinski, Voller et al. 2014), but only ~60% of downstream moving juvenile carp in the field (Zielinski and Sorensen 2015).

Aeration

Aerating shallow, winterkill habitat used for carp spawning and nursery areas should reduce recruitment (Bajer, Chizinski et al. 2012). Native centrachids (sunfish) eat carp eggs. Preventing winter anoxia and winterkill of native centrachids promotes carp egg predation and can reduce or eliminate carp reproduction.

The viability of aeration as a management tool varies based on the characteristics of the shallow lake or wetland nursery habitat. If the nursery habitat is relatively small and isolated, preventing winter anoxia and sustaining a significant sunfish population is possible. If the nursery habitat is large, encompassing many basins, it may not be feasible to prevent anoxia throughout the system. Additional considerations include insurance needs (MNDNR requires specific insurance policies before granting aeration permits) and public safety, as winter aeration creates thin ice and/or open‐water during winter. Aeration systems also have notoriously maintenance costs and personnel requirements.

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Genetic Engineering

This tool is an emerging technology currently under development at the University of Minnesota. The method would involve genetic editing of adult carp. These genetically modified carp would be released into a population, where they would spawn with non‐GM carp. However, the carp larvae would not be viable, or they may only produce male offspring. Testing continues in in 2019; it may be many years before this method is approved by regulatory agencies for field use.

Adaptive Management Approach

Past management efforts for common carp, in the Rice Creek Watershed District and elsewhere, have found mixed success. Carp have shown avoidance behaviors to certain management methods and tools following initial use, demonstrating learning capabilities (Bajer, pers. comm.). Additionally, carp migration and habitat use could change following management efforts. Complex systems (i.e. highly connected, with many shallow wetlands and lakes) provide opportunities for food resources and spawning habitat. The most successful outcomes from past management efforts have been achieved by implementing a comprehensive and flexible approach. Adaptive management principles (Figure 7) provide a framework for program design, implantation, monitoring, evaluation, and (if necessary) course correction. Future technologies and management tools may provide new opportunities to improve the overall program efficiency, effectiveness, or reliability. Once again, the importance of monitoring is highlighted here. A solid understanding of environmental factors and management actions that affect the carp population will be required to assess progress, and alter strategies when needed.

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Assess Design Progress Strategy

Adaptive Management

Evaluate Implement

Monitor

Figure 7. Adaptive management

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System Plans

Individual system plans are developed and updated separately from this document.

 Long Lake / Lino Chain of Lakes [UPDATED December 2018]

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Literature Cited

Bajer, P. G., et al. (2012). "Variation in native micro‐predator abundance explains recruitment of a mobile invasive fish, the common carp, in a naturally unstable environment." Biological Invasions 14(9): 1919‐1929.

Bajer, P. G., et al. (2018). "Field test of a low‐voltage, portable electric barrier to guide invasive common carp into a mock trap during seasonal migrations." MANAGEMENT OF BIOLOGICAL INVASIONS 9(3): 291‐ 297.

Bajer, P. G., et al. (2014). Develpment and implementation of a sustainable stratagy to control common carp in the Riley Creek chain of lakes, University of Minnesota.

Bajer, P. G., et al. (2015). "Partial migration to seasonally‐unstable habitat facilitates biological invasions in a predator‐dominated system." Oikos 124(11): 1520‐1526.

Bajer, P. G. and P. W. Sorensen (2009). "Recruitment and abundance of an invasive fish, the common carp, is driven by its propensity to invade and reproduce in basins that experience winter‐time hypoxia in interconnceted lakes." Biological Invasions.

Bajer, P. G. and P. W. Sorensen (2012). "Using boat electrofishing to estimate the abundance of invasive common carp in small Midwestern lakes." North American Journal of Fisheries Management 32(5): 817‐ 822.

Bajer, P. G. and P. W. Sorensen (2015). "Effects of common carp on phosphorus concentrations, water clarity, and vegetation density: a whole system experiment in a thermally stratified lake." Hydrobiologia 746(1): 303‐311.

Bajer, P. G., et al. (2009). "Effects of a rapidly increasing population of common carp on vegetative cover and waterfowl in a recently restored Midwestern shallow lake " Hydrobiologia 632: 235‐245.

Banet, N. V. (2016). Partial migration, homing, diel activity, and distribution of adult common carp across a large, model watershed in the North American Midwest. Food, Agricultural, and Natural Resources Sciences. St. Paul, MN, UNIVERSITY OF MINNESOTA. Master of Science: 139.

Lechelt, J. D., et al. (2017). "Low downstream dispersal of young‐of‐year common carp from marshes into lakes in the Upper Mississippi River region and its implications for integrated pest management strategies." MANAGEMENT OF BIOLOGICAL INVASIONS 8(4): 485‐495.

Parkos III, J. J., et al. (2003). "Effects of adult common carp (Cyprinus carpio) on multiple trophic levels in shallow mesocosms." Canadian Journal of Fisheries and Aquatic Science 60: 182‐192.

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Schrage, L. J. and J. A. Downing (2004). "Pathways of increased water clarity after fish removal from Ventura Marsh; a shallow, eutrophic wetland." Hydrobiologia 511(1‐3): 215‐231.

Weber, M. J. and M. L. Brown (2009). "Effects of common carp on aquatic ecosystems 80 years after "Carp as a Dominant": Ecological insights for fisheries management." Reviews in Fisheries Science 14(4): 524‐537.

Weber, M. J. and M. L. Brown (2015). "Biomass‐dependent effects of age‐0 common carp on aquatic ecosystems." Hydrobiologia 742(1): 71‐80.

Zielinski, D. and P. Sorensen (2015). "Field test of a bubble curtain deterrent system for common carp." Fisheries Management and Ecology 22(2): 181‐184.

Zielinski, D., et al. (2014). "Laboratory experiments demonstrate that bubble curtains can effectively inhibit movement of common carp." ecological engineering 67: 95‐103.