June 2015 Newsletter
Letter from the Director
Dear Friends -
I am often asked how the Minnesota Aquatic Invasive Species Research Center determines what issues to research. There are many issues yet to be addressed in this arena, and many species to consider– including the emerging threats of new AIS that are at our doorstep. The sheer number of options can sometimes feel daunting. Of course, we wish we could cover everything, but we can't. We have to prioritize the issues of top concern, the research with the highest likelihood for developing prevention and control options, and the projects that most effectively use public research dollars.
That's why last fall I initiated MAISRC's first-ever comprehensive Research Needs Assessment, preliminary results of which I'm excited to share with you today. These new projects have no impact on our current research projects, which were planned as part of MAISRC's establishment.
When it came to determining new projects, emotions and possibility were both running high. In order to be as strategic as possible, a diverse assessment team with a breadth of scientific expertise was established. This team worked to take into consideration the gamut of scientific and social issues that surround AIS in Minnesota and took into account input from AIS managers around the state, other scientists, and the public.
What resulted were seventeen research topics that will guide new investments in the coming year. These topics range from determining the likelihood of spread of zebra mussels by various mechanisms (boat lifts, docks, residual boat waters, etc.) to developing Asian carp deterrents for use in small waterways. Some topics, including research on Eurasian watermilfoil and curly-leaf pondweed control options, have already been targeted for implementation.
Six more projects – ranging from open-water pesticide treatment analysis for zebra mussel infestations, metagenomic approaches to biological control strategies of zebra mussels and Eurasian watermilfoil, and developing carp-specific toxins – will be launched by August, and an open call for research proposals will be announced soon after that with an aim to begin new work in 2016.
Of course, MAISRC might not be able to address all seventeen of the priorities included on the list. However, we will work across as many fronts as possible to implement the quality, scientific research that all Minnesotans expect from the University. In order to stay on top of changing AIS conditions, the priorities list will be revisited and updated every one to two years and new projects will be considered. As needs and opportunities emerge, new funds will be sought to advance additional research that align with MAISRC's mission.
It is exciting to be on the cusp of this significant step forward in our work – and I thank you for the ideas and support you have provided to get us here.
I look forward to sharing details of the new research efforts as they are launched!
Dr. Susan Galatowitsch
Director, Minnesota Aquatic Invasive Species Research Center
Lessons learned at Christmas Lake
Many of you have probably already heard – and possibly felt dismayed by – the recent news that divers discovered ten zebra mussels in Christmas Lake after it was treated using Zequanox, copper, and potash last fall and winter.
The efforts at Christmas Lake are not part of a controlled experiment, rather a real-life rapid response attempt by lake managers to kill a newfound infestation of zebra mussels. MAISRC researcher Dr. Michael McCartney has been serving as an advisor to the management team led by Minnehaha Creek Watershed District and the Minnesota Department of Natural Resources.
"Participating in an open lake treatment such as this has been an extremely valuable opportunity," says McCartney. "It's more challenging to get the cause and effect data without controlled conditions, but we are still able to learn important lessons that will guide future attempts." Some of what McCartney says he has learned from this experience includes the following:
- We now have a better estimate of the short-term mortality rates achievable with pesticide treatments. Under open-water conditions such as Christmas Lake, treatments showed that pesticides killed 100% of zebra mussels in the treatment area, and approximately 98% of zebra mussels in the lake. This is among the highest kill rates ever documented for an open-water treatment of zebra mussels and is overall a very positive outcome. The long-term impact this will have on the lake population of zebra mussels, however, is still unknown, and will require longer-term study of lakes, including Christmas.
- Removing the impermeable barrier in a timely fashion is important. Marrone Bio Innovations (the manufacturer of Zequanox®) recommends leaving an impermeable barrier in place around the treatment area for a maximum of 24 hours. When left longer, as happened at Christmas Lake, a decline in dissolved oxygen can occur for as long as the barrier is retained, which increased the risk of impact to non-target organisms. This also complicated the conclusion that zebra mussel mortality in the first treatment was due to Zequanox® and not also to the lack of available oxygen, and it confounds the evaluation of Zequanox® mortality from this open water treatment.
- There are challenges in maintaining proper pesticide concentrations in open water scenarios. The second treatment at Christmas Lake used the EarthTec QZ® brand of copper sulfate. Workers discovered that upon application, concentrations of the pesticide dropped rapidly – to below the lethal level for zebra mussels. This prompted the need for continued monitoring and adjustment of concentration of the pesticide to maintain the lethal dose. It is hypothesized that this drop is due to uptake of the copper sulfate by lake organisms – probably algae – however this remains to be further studied.
- Under-ice application of Potash is not a viable option at this time. Researchers discovered that it was too difficult to maintain evenly dispersed, toxic doses of potash when applied under the ice. It is not clear to what extent these problems related to cold water or to restricted water circulation. Potash may still be a viable option during warmer months if permitting and labeling regulations allow for it.
- Scientifically-based survey methods are needed to establish treatment areas and to evaluate treatment outcomes. When divers searched for signs of mussels in April, they came up empty, suggesting that no mussels remained in the lake after treatment. In May, workers searched again and found ten adult mussels just outside the treated area. Survey and census methods prior to treatment may be improved as a result, to give future workers a better chance of making the treatment area large enough, given uncertainty in the spatial extent of an infestation. Improved survey methods after treatment, developed in part from lessons learned on Christmas Lake, are expected to also give future workers a clearer view of the abundance and distribution of the lake zebra mussel population. This information is needed to better evaluate how the lake population responds to the treatment, and to plan any follow-up efforts.
- Prevention is still the best option. The scenarios being tested at Christmas and other lakes are those in which the infestation has been detected before the zebra mussel population has expanded or dispersed beyond a very small area (in Christmas Lake, infestation was initially believed to be confined to ~0.1 acres). Whole lake treatment by any of these three pesticides is not a viable option due to cost, non-target impacts, and technical challenges including those described above. Much work is needed to understand potential controls for zebra mussels. In the meantime, the best option for our lakes and rivers is to prevent these species from being introduced in the first place.
While McCartney continues his research on understanding pathways of zebra mussel spread in Minnesota, he is also working to expand his research portfolio by evaluating the long-term effectiveness of pesticide use to control lake populations of zebra mussels. As part of this additional effort, McCartney will focus on developing and refining sampling protocols to be used in future pesticide treatments. Not only will this potentially improve treatment results, it also will allow for the collection and sharing of data so other managers around the state can learn from these early efforts at Christmas– and other lakes as well.
Partial migration: new findings suggest management opportunities for common carp
The phenomenon of partial migration – when some individual animals migrate seasonally while others of the same species remain in place – is relatively common in the natural world and generally has positive impacts on the stability and abundance of native populations. However, many invasive animals employ this tactic as well, leading MAISRC researcher Przemek Bajer to ask how partial migration may be leading to the success of the ubiquitous and detrimental common carp.
Newly published research from MAISRC now suggests that common carp engaging in partial migration to exploit outlying marshes for better spawning areas may be an important factor that leads to their enhanced abundance.
To conduct this research, MAISRC partnered with computer programmers and fish biologists to develop an individual-based, age-structured population dynamics model of carp in Minnesota lakes. They modelled carp movement through numerous scenarios including varying ages, migration patterns, and winterkill frequencies. Ultimately, results showed that common carp are unlikely to become excessively abundant in lakes in central Minnesota unless they conduct partial migrations to marshes that experience winterkill.
Lakes and marshes that experience winterkill (a natural occurrence in which many fish die due to a lack of oxygen) will then lack the egg and larval predators – such as bluegills – which would normally act as a control for common carp populations. Without these native predators, common carp populations can continue to grow unchecked, leading to increased population success.
Interestingly, carp were found to be most abundant if marshes winterkilled with low frequency (roughly every 3 – 20 years). More frequent winterkills ultimately led to population declines, because some adults (and most juveniles) became stranded in the winterkill habitat.
These findings suggest specific management opportunities: whereas some marshes could be aerated to eliminate winterkills, others could be mixed during winters to promote winterkills to control juveniles and adults that decide to overwinter in marshes. Behavioral deterrents (such as acoustic barriers) that slow down the movement of juveniles from marshes into lakes could also be beneficial. The carp population dynamics model developed in this study could be used to determine exactly which strategies might be most beneficial for a particular system of lakes.
Common carp are one of the world's most invasive species and have long been a problem in Minnesota lakes. Ultimately, having a better understanding of how they are able to become successful helps inform control strategies. Learning about the role of partial migration into winterkill-prone areas adds another piece to the puzzle.
Read the full paper, "Partial migration to seasonally-unstable habitat facilitates biological invasions in a predator-dominated system," online here.
This project was funded by the Minnesota Environmental and Natural Resources Trust Fund and the Riley Purgatory Bluff Creek Watershed District and was conducted in partnership with the Minnesota Department of Natural Resources.
Do your part to advance research on AIS biocontrols and emerging diseases by reporting fish kills
Chances are, you've encountered a fish kill event at some point in your life. Fish kill events in Minnesota are widespread. Not only can these localized die-offs ruin your beautiful photo or private fishing spot, they can also provide clues of greater ecosystem-level issues such as Viral Hemorrhagic Septicemia virus (VHSv), water quality degradation, climate change, and invasive species.
The Minnesota Department of Natural Resources estimates that there are about 500 fish kill events per year, the vast majority of which go unreported. That's where MAISRC researcher Dr. Nick Phelps, a user-friendly new reporting database, and you come in.
Reporting fish kill events that you see is an easy and effective way to do your part to help protect Minnesota waters. The online, user-friendly database is available now at http://z.umn.edu/fishkill. It simply asks for the date, the location of the fish kill, and other basic information of any fish kill you observe. Once reported, fish kills are triaged and, if appropriate, trained biologists and students will collect samples to diagnose the cause of mortality.
"It's important to study and monitor fish kills to prepare, identify, and respond to new threats to fish populations in Minnesota," said Phelps. "We can't be everywhere at once, so we need the public's help with this. When you report a fish kill, you're helping us better understand trends over time which will ultimately lead to proactive management strategies and mitigating risks."
Although all fish kills should be reported, ongoing MAISRC research led by Phelps will focus specifically on investigating carp fish kills. The goal of this project is to find new or emerging diseases of concern in these highly invasive fish, as potential biocontrol options that are lethal to carp but have no effect on native species.
So while you're out and about this summer enjoying our beautiful lakes, rivers, and streams, do your part to advance research, help the Minnesota Aquatic Invasive Species Research Center, and protect our waters by reporting fish kill events that you see.
New answers in optimizing techniques to capture and extract environmental DNA for detection and quantification of carp
Aquatic invasive species are already a vexing challenge: they're new, they don't have very many predators, and they often move freely and quickly among waters. Add to that the difficulty of determining whether a species is present in an area without being able to physically see it. That's the challenge that MAISRC researchers who study eDNA are working to address.
Environmental DNA (eDNA) is a method used to measure the presence – and in some cases, the abundance – of invasive species by detecting fragments of DNA shed by the organism in water. It is likely much more sensitive than traditional AIS monitoring techniques – a primary reason why eDNA is currently used to monitor for Asian carp.
There are many methods in use today to capture (concentrate eDNA from water) and extract (purify the DNA in a water sample prior to analysis) eDNA, but few studies have sufficiently examined which techniques are optimal. Identification of optimal methods is extremely important for sensitive detection – use of sub-optimal methods could result in the failure to detect eDNA and the failure to recognize and take action in the early stages of AIS invasion.
In order to determine the optimal eDNA methodology, MAISRC researchers Jessica Eichmiller, Loren Miller, and Peter Sorensen studied several widely used eDNA capture methods as well as six commercially available DNA extraction kits. They were all evaluated for their ability to detect and quantify common carp mitochondrial DNA.
MAISRC researchers determined that optimal capture and extraction methods differed based on the goal – whether quantification or detection of the carp. While filtration capture performed better than precipitation and centrifugation for both detection and quantification, filter characteristics, such as pore size, affected the recovery of eDNA. In addition, researchers found tradeoffs among DNA extraction kits between the total DNA yield and the kit's ability to remove inhibitors. When present, inhibitors – compounds that inhibit the enzymatic reactions that we use to measure the DNA in a sample – make it difficult to detect the DNA and can lead to inaccurate measurements.
MAISRC researchers are currently using the results of this study in a larger-scale field study aimed at improving the ability to measure quantities of common carp through their eDNA. Eventually, the researchers hope to use their findings on common carp to improve methods for detecting and quantifying Asian carp.
"Having more sensitive and reliable detection and quantification techniques, such as eDNA, will allow managers to make informed decisions about appropriate management actions for invasive species," said Eichmiller. For detailed recommendations for eDNA capture and extraction methods, read the full paper, "Optimizing techniques to capture and extract environmental DNA for detection and quantification of fish," online.
Demolition begins at MAISRC's Research and Holding Lab
After months of planning and preparing, demolition is beginning on MAISRC's long-outdated laboratory facility. The outer shell of the facility on the St. Paul campus will remain intact, but inside, the updated lab will soon more accurately reflect MAISRC's state-of-the-art research goals.
Over the next few months, the 10,200-square-foot facility will be completely gutted and overhauled. New and better fish holding tanks will be added and well water treated for use by aquatic organisms will be available at different temperatures to mimic real life systems. New lighting controls will more effectively simulate day and night conditions for plant, fish, and invertebrate studies. The project also includes a new secure storage building for boats and a wash-down area for decontaminating field gear. Water will be collected and treated on-site.
"After renovation, this will truly be one of the best AIS research facilities in the country," said Dr. Susan Galatowitsch, MAISRC Director. "The ability to control light, temperature, and water flow for experiments will create opportunities never before possible for invasive plant research at the U."
"We're really excited and honored to be working on this project for the Center," added Rob Darnell, Project Manager with Burns & McDonnell, the firm responsible for design and construction administration of the space. "We anticipate completing renovations in December and having these important research projects up and operational by January 2016."
Major funding for the renovation was provided by the Minnesota Legislature and the University of Minnesota. Stay tuned for more updates about the lab as construction proceeds.
MAISRC providing incentive grant for student research on invasive fish
The Minnesota Aquatic Invasive Species Research Center, in partnership with the Introduced Fish Section of the American Fisheries Society, is awarding funds of up to $500 to support student research aligning with MAISRC strategies of advancing understanding of the basic biology or ecology of invasive fish within the Upper Mississippi River Basin in order to more effectively control them. This special award will support student travel to present findings at the American Fisheries Society annual meeting held in Portland, Oregon in August 2015.
To win, a student must be a member of the Introduced Fish Section, give an oral or poster presentation at the meeting, and attend the IFS Business Meeting. Learn more and apply here. The American Fisheries Society works to advance sound science, promote professional development, and disseminate science-based fisheries information for the global protection, conservation, and sustainability of fisheries resources and aquatic ecosystems. The Introduced Fish Section works specifically on identifying and researching the potentially harmful impacts of introduced species and is led by MAISRC researcher Przemek Bajer.
MAISRC researcher invited to present at international Fish Passage conference
MAISRC postdoctoral research associate Dan Zielinski has been invited to present at Fish Passage 2015: an international conference on river connectivity best practices and innovations. Dr. Zielinski will discuss preliminary findings of his research into manipulating water flows through the lock and dam structures on the Mississippi River in order to block Asian carp – while still permitting native species to pass.
Silver carp have been found in Pool 2 of the Mississippi River and Bighead carp in the St. Croix River just south of Stillwater. Successfully reproducing silver and bighead carps are known to be in the Mississippi River as far north as Keokuk, Iowa. MAISRC is working hard to research and develop various integrated deterrent systems to stop these destructive fish, including the acoustic deterrent system discussed in the last newsletter.
Watch for updates on Dr. Zielinski's findings in future editions of AIS Spotlight.
Thank you to the Polasik family!
MAISRC is thrilled to thank Tom and Dianne Polasik as advisors for the Lee S. and Dorothy N. Whitson fund of the St. Paul Foundation for their very generous recent donation to the Minnesota Aquatic Invasive Species Research Center. The gift will be used to buy a boat, trailer, and motor, which will be put to immediate use this summer for field work on invasive carp.
MAISRC researchers Jessica Eichmiller, Ratna Ghosal, and Aaron Claus will use the boat to track common carp, set up bait stations for sexual and food stimuli, and collect water samples as part of a new research project that will be announced later this summer.
The project will mark an important step in moving from lab to field testing of the use of food and sexual cues to aggregate carp in certain areas so they can be reliably measured (and ultimately removed). This work is the second phase in developing an integrated plan for Asian carp and is a key component of the Minnesota Invasive Carp Action Plan.
The faculty, staff, and students at MAISRC are very grateful for support from individuals which truly help make our work possible. Please consider a tax-deductible gift to MAISRC today. Your donations allow us to respond quickly and with flexibility to emerging AIS issues and needs.