June 2016 AIS Spotlight

Letter from the Director

Dear friends -

sueAs you may already know, I am soon passing the baton of MAISRC leadership to Dr. Nicholas Phelps, currently a faculty member with the Center. I will be returning to my position as a professor, researcher, and head of the Department of Fisheries, Wildlife, and Conservation Biology, and I look forward to helping Dr. Phelps with the transition.

It has been an honor to serve as director of the Center for the last two years. In addition to overseeing 21 unique research projects covering 10 different aquatic invasive species, I've had the pleasure of implementing a systematic research needs assessment process to prioritize research investments with input from stakeholders; creating a new full-time, tenure-track research and outreach position; launching several new collaborations with the Minnesota DNR, Sea Grant, and others; and leading the creation of a ten-year strategic plan. And to top this all off, I'm excited today to announce several new research projects that the Center is launching this summer! These include:

  1. Evaluating four zebra mussel controls and developing protocols for their use on new, localized infestations
  2. Characterizing long-term spiny waterflea ecosystem impacts using soil sediments
  3. Risk assessment, control, and restoration research on starry stonewort, Eurasian watermilfoil, curly leaf pondweed, and hydrilla
  4. Lake-scale prediction of invasion, survivability, and effects of various management interventions on the spread of three AIS in Minnesota
  5. Partnering with the Minnehaha Creek Watershed District and Hennepin County to evaluate the potential for larger scale treatment of veliger-infested waters

Look for more detail on these projects in this and upcoming newsletters.

In order to do all that I can to ensure continuity with research, there will be an approximate year-long transition period during which Dr. Phelps and I will serve as co-directors. Dr. Phelps has great energy and enthusiasm for the work that needs to be done to find solutions to AIS problems in Minnesota. He currently has several research projects underway with the Center that address a range of issues including Asian carp biocontrol, threats to gamefish by harmful viruses, invasiveness of starry stonewort, and predicting zebra mussel spread using boater movement and other risk factors.

Please join me in welcoming Dr. Phelps to his new position, and thank you for your support of the Minnesota Aquatic Invasive Species Research Center during my tenure.

Dr. Susan Galatowitsch

Director, Minnesota Aquatic Invasive Species Research Center
Head, Department of Fisheries, Wildlife, and Conservation Biology

New suite of research on aquatic invasive plants kicks off

hydrillaStarting this summer, MAISRC researcher Dr. Dan Larkin is launching new research on four invasive plants of great concern in Minnesota: hydrilla, starry stonewort, curly-leaf pondweed, and Eurasian watermilfoil.

The research needed for these plants varies depending on their stages of invasion in Minnesota and what is already known about the species. Therefore, research will include:

  • Hydrilla, a very harmful aquatic invasive species that is present in the U.S. but not yet in Minnesota. Using ecological modeling and conducting laboratory growth experiments, our research team will test how hydrilla performs under different climate scenarios for Minnesota. We will then create a risk map showing regions of predicted low to high suitability for hydrilla, factoring in the warmer winters that may result from climate change. This will help target early detection efforts. 
  • Starry stonewort, Minnesota's newest invader, shows preference for some lake environmental conditions over others. Researchers will apply this knowledge to predict which Minnesota lakes are most at risk of this invasive algae surviving and expanding should it be introduced. In the lab, we will test how long this species' fragments and reproductive structures can remain viable out of water to understand risk of overland spread by boaters. Finally, we will test the efficacy and selectivity of different herbicides to control starry stonewort where it has invaded.
  • Curly-leaf pondweed and Eurasian watermilfoil, two of Minnesota's most established and long-researched invasive plants. Our ability to effectively control these species and to support the recovery of native plants is still limited. In partnership with MAISRC's citizen-science program, this research will conduct new field work and analyze existing datasets to improve our understanding of factors that drive invasion of these species and influence the effectiveness of management efforts. Additionally, in partnership with the U.S. Army Corps of Engineers, researchers will conduct lab work, research on phenology, and testing of growth rates and competitive interactions between native, Eurasian, and hybrid milfoils.

As part of this program, Dr. Larkin recently convened a group of international experts at the University of Minnesota to identify knowledge gaps and research priorities for preventing and managing invasion by starry stonewort. The group included scientists and resource managers from the New York Botanical Garden, Central Michigan University, UW-Stevens Point, the Minnesota DNR, and the University of Geneva in Switzerland.

"A lot is still unknown about this invasive algae," said Larkin. "In order for MAISRC to support sound, science-based management, it was critical that we synthesize what is and is not known about this new invader." If you missed it, you can watch a recording of the webinar here.

Aquatic invasive plants can form dense mats on the surface of lakes and rivers, reducing space and light available to other plant species. This can lower native plant diversity, reduce habitat quality for fish and other animals, and change the way lakes function. They can also interfere with boating, recreation, and other human uses. Learn more about these plants and our research here.

New MAISRC research shows invasive common carp more damaging to biodiversity than human development 

carpNew, first-of-its-kind research from MAISRC is adding to the evidence that biological invaders – such as zebra mussels, rusty crayfish, and Asian carp – are threatening to be the main driver of biodiversity and ecosystem function loss in lakes in the 21st century.

Because many of these invasions are relatively new, their impacts are not always readily apparent. The impacts can also be confounded with those caused by other stressors. That is why this team of researchers – led by Dr. Przemek Bajer – focused on the century-old invasion of common carp to illustrate the potential consequences of introducing non-native ecosystem engineers to lakes worldwide.

They found that when common carp were prolific, plant cover was reduced to less than 10% and species biodiversity was halved. By teasing out the impacts of other human-caused stressors, this research also revealed that carp had a greater impact on aquatic plant biodiversity than human watershed development did.

"Understanding the importance of biological invasions relative to other stressors is highly important to ecologists, policymakers, and lake managers," said Dr. Bajer. "By showing that invasive species are such an important driver of ecosystem change, this research demonstrates the value of curbing introductions of these and other non-native species."

For the study, researchers analyzed data from over 2,000 Minnesota lakes, covering our three major ecoregions of Great Plains, Eastern Temperate Forests, and Northern Forests. They also conducted whole lake experiments in six lakes in which they established what the current carp populations were, surveyed plant cover, and identified species richness both before and after removing carp. All four study lakes (two served as controls) showed that removing common carp increased plant cover, species richness, and water clarity. To evaluate the contributions from human development, the team used the proportion of land used by humans for urban developments and agriculture within the watersheds. They then used statistical models to determine which variable caused the most impact.

Common carp are known for increasing water turbidity and uprooting aquatic plants while searching for food in the sediment. The associated loss of plant cover and biodiversity can have a cascading effect on the abundance and diversity of waterfowl, insects, and amphibians and can hinder fundamental ecosystem functions such as maintaining water clarity, reducing erosion, and sequestering nutrients. Learn more about common carp here

Developing rapid response protocols for zebra mussel treatment

zmIn partnership with the USGS, the Minnesota Aquatic Invasive Species Research Center is launching a new project to develop a set of rapid response protocols for treating localized zebra mussel infestations. The protocols, which will take water temperature into account for the first time, will provide managers with a critical support tool to swiftly select the correct molluscicide, determine the treatment concentration, and determine the treatment duration.

The project will also help determine the probability of treatment success and estimate the treatment costs. Four molluscicides will be evaluated – Zequanox, Earthtec QZ, potassium chloride, and niclosamide.

Previous studies have shown that fluctuating water temperatures can be a major factor in determining the zebra mussels' sensitivity to toxicants. For example, Earthtec QZ is a copper-based product that has been found to effectively kill zebra mussels, but water temperature influences the toxicity of the copper ions.

"This project seeks to eliminate those unknowns about dose and duration under various water temperatures," said lead researcher Jim Luoma, a fisheries biologist with the USGS's Upper Midwest Environmental Services Center.

"This will be an important support tool for use in those situations by the Minnesota DNR, watershed districts, and lake management professionals," said MAISRC's invertebrate expert, Dr. Michael McCartney. "Early detection and response within the first year after discovery is apt to be our best management option; populations are small and mussels are likely to be localized to small areas that can be treated and have a shot at preventing explosive population growth."  

There have been two early detection and rapid response eradication attempts in Minnesota, on Christmas Lake and Lake Independence, where the infestation was believed to be highly localized. Both of these eradication attempts were hindered by a lack of water temperature-specific protocols, particularly regarding the choice of molluscicide and the dosing regimens as water temperatures were decreasing. Learn more about zebra mussels here.

New MAISRC paper concludes VHS risk in Great Lakes region still high

vhsThe deadly disease Viral Hemorrhagic Septicemia virus will continue to be a threat for fish in the Great Lakes region, a new paper from MAISRC researchers Dr. Luis Escobar and Dr. Nick Phelps confirms. This paper builds upon previous MAISRC research, greatly expanding the scope beyond Minnesota and telling a broader, more complete story about VHS ecology and risk.

Escobar and his partners used a process called ecological niche modeling to predict which waterbodies are most at risk for the virus, taking into account daytime and nighttime temperature, precipitation, vegetation, bathymetry, solar radiation, and topographic wetness. Knowing the conditions that VHS can survive in, including its preferred temperatures, researchers were able to identify areas of high to low suitability for the virus.

They found that in much of the Great Lakes area, VHS virus has not yet reached "ecological equilibrium" – suggesting that there are still areas into which it can expand. In addition to the Great Lakes and inland lakes, rivers were also found to be suitable to support VHS. Infectious diseases like these in wild fish are a worrisome threat not only for biodiversity, but also for potential spillover to farmed fish.

Understanding what areas are at the highest risk for VHS occurrences is key for surveillance strategies, and can inform management plans for prevention and resource allocation. Going forward, researchers will expand and improve the model by including additional variables such as water flow, boater movement, baitfish and fish stocking, and river connectivity to understand the risk of VHS in Minnesota and beyond.

VHS is considered to be the most significant freshwater fish health threat in the world and can cause large-scale fish kills. It is transmitted fish-to-fish from close contact of contaminated water or reproduction. It is known to infect many popular game fish species such as Walleye, Muskellunge, Salmonids, and Bass. It has been confirmed in all of the Great Lakes but not yet detected in inland waters of Minnesota.

You can read the paper, Potential distribution of the viral hemorrhagic septicemia virus in the Great Lakes region, here


Disseminating MAISRC research findings

MAISRC researcher Nate Banet recently presented at the Washington – British Columbia American Fisheries Society's annual meeting. His talk, "Migration and Homing of an Invasive, Freshwater Fish: Identifying Integrated Pest Management Strategies for Common Carp in Interconnected Systems" included the latest updates on his thesis research. Banet's research is showing that understanding annual migration patterns of common carp can assist in guiding control strategies not only in Minnesota but also in other regions like the Northwest. 

This June, MAISRC postdoctoral research associate Adam Kokotovich presented an update on his team's Asian Carp risk assessment to the St. Croix River Association's aquatic invasive species group. The risk assessment identified a list of potential adverse effects that could result from the establishment of Asian carp in Minnesota as well as the primary tensions and conflicts in Asian carp management. You can read a working paper, Exploring tensions and conflicts in invasive species management: The case of Asian carp, here.

MAISRC researchers Nick Phelps, Luis Escobar, and Megan Tomamichel presented in June at the American Fisheries Society's Fish Health annual meeting. Phelps presented on novel invasive viruses in baitfish, Escobar on the potential distribution of Viral Hemorrhagic Septicemia virus, and Tomamichel on Heterosporis.

New paper published on masculinizing fish

MAISRC researchers Dr. Ratna Ghosal and Dr. Peter Sorensen recently published a new paper on masculinizing goldish, a relative of carp. Many fish are capable of exhibiting either male or female behavior if exposed to appropriate hormones at the right time. Ghosal and Sorensen researched whether goldfish can be masculinized with 100% effectiveness for use as a Judas fish and found that they cannot. They are now exploring feminizing as an alternative method.

You can read the paper, Male-typical courtship, spawning behavior, and olfactory sensitivity are induced to different extents by androgens in the goldfish suggesting they are controlled by different neuroendocrine mechanisms, online here.

MAISRC welcomes new researchers

MAISRC is pleased to welcome several new researchers to our team:

Donn Branstrator, associate professor with the University of Minnesota – Duluth, and Euan Reavie, senior research associate with the University of Minnesota – Duluth, working together to characterize the long-term ecosystem impacts of spiny waterflea

Jim Luoma, a research fisheries biologist with the USGS, evaluating zebra mussel control options

Jean Finger is a Postdoctoral Research Associate working with the Sorensen team on testing the effects of sound barriers on native fish and common carp, and will be validating the Sorensen team's lock and dam fish passage model using real data.

Hannah Dunn is a junior scientist working with Dr. Michael Sadowsky on characterizing the microbial communities associated with aquatic invasive species using metagenomic approaches.

Andrew Riesgraf is a researcher working with the Sorensen team researching fish movement around lock and dam 2 in Hastings, in order to learn more about properly deploying control technologies.

TJ Ostendorf is a researcher in the Newman lab assessing the relationship between milfoil weevils and sunfish populations in order to increase the herbivore's potential to control Eurasian watermilfoil.

Connor Erickson is a graduate student in the Sorensen lab, researching pheromones, spawning attraction, and aggregation in carps in order to increase the efficacy of the Judas fish technique.


The Minnesota Aquatic Invasive Species Research Center is delighted to thank the Tonka Bay Marina and the Brunswick Freshwater Boat Group – maker of Lund and Crestliner boats – for their recent support of new research aimed at reducing the spread of invasive zebra mussels by recreational boaters. This project, which is also being supported by the Minnesota DNR, will examine the spread of zebra mussels from "residual water" — water left in a boat after its operator has attempted to fully drain it.

You can lend your support to this project or any of MAISRC's solutions-oriented work by donating today. Private donations truly make a difference to our work and provide us with the flexibility to meet critical needs as they arise. Thank you!

Sign up here to receive AIS Spotlight directly in your inbox.