February 2018 newsletter
Letter from the Director
Hello from the Minnesota Aquatic Invasive Species Research Center!
A couple of months ago, we issued a Request for Proposals (RFP) to address Minnesota’s highest priority research needs to prevent, control, and manage aquatic invasive species. This is our third competitive RFP, open to all Minnesota-based researchers and their collaborators. This process has served the state well, as it focuses research on high-priority needs and evaluates the quality of the science to ensure the best bang for the research buck.
This year, we received 20 proposals requesting a total of $4.2 million – both new records! This was a good new, bad news situation. It was amazing to see the innovation, creativity and value proposed by many of the researchers and I wanted to support many more than we could. Unfortunately, we only have the funding to support five projects this year and very hard decisions were made to select the top projects. Those investigators are currently working on full proposals that will be sent out for scientific peer-review in the coming months – stay tuned for details as they are finalized!
Time to get back to the lab…
Dr. Nick Phelps, Director
Research on starry stonewort treatments informs management efforts
A forthcoming paper from MAISRC researchers and their collaborators will help inform starry stonewort management efforts in Minnesota lakes. Researchers found that mechanical and algaecide treatments greatly reduced starry stonewort biomass, but that bulbils – small, star-shaped structures that can regenerate into new plants – remained viable after treatment.
The project consisted of both field and lab work to evaluate the effects of mechanical and algaecide treatments on starry stonewort biomass, bulbil density, and bulbil viability. Researchers examined several areas of the lake that had undergone different treatments, including a channel that was mechanically harvested, an area that was treated only with algaecide, and an area that was first mechanically harvested and then treated with algaecide. The results of each treatment were compared to an untreated reference area. This research was conducted in collaboration with the Koronis Lake Association and Blue Water Science, a lake management firm. Key findings included:
- The algaecide (chelated copper) treatment on its own significantly reduced starry stonewort biomass, but failed to reduce bulbil density and the capacity of starry stonewort to regenerate via bulbils.
- Combining the algaecide treatment with mechanical harvesting also significantly reduced starry stonewort biomass, and was associated with lower bulbil viability.
These findings underscore that a multi-pronged approach to starry stonewort control that includes both chemical and mechanical management has potential to improve outcomes. Determining how to prevent the recovery of starry stonewort from bulbils that remained viable after treatment needs further investigation.
Applied research on the efficacy of starry stonewort treatment options has been extremely limited; MAISRC is filling a critical knowledge gap with this work. The paper will be published in Lake and Reservoir Management this spring.
This invasive alga has now been found in eleven Minnesota lakes and can grow tall and dense, interfering with recreation and potentially displacing native species. To date, treatment options have been limited and the species has proven difficult to control. Stay tuned to our website for more information and updates about starry stonewort.
A team of MAISRC researchers recently completed first-of-their-kind experiments on the use of bluegill sunfish for the biocontrol of common carp. They found that bluegill predation had a significant effect on common carp recruitment and that bluegills could be harnessed to reduce carp’s reproductive success. While previous evidence had suggested this possibility, it had never before been tested experimentally in natural lake systems.
Bluegills already naturally control carp in some lakes by consuming their eggs and larvae. But because bluegills often don’t live in marshes due to winterkill, carp have learned to migrate there to spawn. This research set out to evaluate whether increasing bluegill populations throughout the year, using tactics like aeration, would limit carp populations.
To conduct this research, MAISRC graduate student Josh Poole, led by his advisor Dr. Przemek Bajer, selected six small experimental lakes in 2016 and 2017. Each lake was big enough to have natural properties like a littoral zone with vegetation and internal food webs. They stocked bluegills in half of the lakes, waited until the carp had spawned and for their young to hatch and become free-swimming, and then sampled for carp during three different life stages.
The results indicated that bluegill predation had a significant effect on the abundance of post-larval carp, which were approximately nine times fewer in lakes with bluegills than those without.
“To our knowledge, this is the first experiment on the biocontrol of an invasive fish conducted using whole-lake manipulations over multiple seasons,” said Poole. “These results are applicable to the management of carp in shallow, productive lakes – like many found in southern Minnesota. It highlights the usefulness and benefits of winter aeration to keep bluegills alive in shallow marshes.”
“While biocontrol has many benefits, it is not a silver bullet,” added Dr. Bajer. Its applicability will vary among lakes. For example, some extremely shallow marshes may not be able to support abundant bluegill populations. Nevertheless, the use of biocontrol and winter aeration could and should be considered in many locations.”
Several tactics are currently in use to control common carp, such as winter seining for aggregations and electric barriers – both of which have benefits and major drawbacks. Researchers have been searching for a method to control carp that will be less labor-intensive and more successful. This team also completed a complementary set of preliminary tests to evaluate integrating a toxin into carp-specific bait. This project, which has now been tested in the lab and small, man-made ponds, will be moving to larger, more natural ponds and lakes later this year.
Common carp are one of the country’s most ubiquitous invasive species, but MAISRC has made significant strides toward controlling them. They cause damage to the ecosystem by rooting around in the bottom sediment for food, which reduces water clarity and contributes to harmful algal blooms, eutrophication, and habitat loss. Learn more about common carp and additional MAISRC research here.
If you’re looking for a fun way to get involved with your community and help protect area lakes, consider joining the AIS Detectors program this spring. The program was created by the Minnesota Aquatic Invasive Species Research Center and University of Minnesota Extension, and trains participants in:
- The basics of aquatic ecology
- AIS identification, impacts, and biology
- Minnesota rules and regulations
- Preventing the spread of AIS
- Reporting possible invasions
Upon completing the training, participants are equipped to volunteer around the state and make a difference in the areas of citizen science, outreach and education, stewardship, and support of AIS programs.
As a participant, you’ll first take an online course that can be completed on your own time from home, at a public library, or anywhere else with access to the internet. Then, you’ll attend one in-person, full day workshop where you’ll apply the knowledge and skills that you learned in the online course. Workshops will be held the following days and locations:
- April 20 in Arden Hills
- April 27 in Victoria
- May 4 in Owatonna
- May 11 in Willmar
- May 17 in Brainerd
- June 1 in Duluth
Learn more details about the program and find information about registration at www.AISdetectors.org.
Did you hear the news? The Minnesota Aquatic Invasive Species Research Center just marked its fifth anniversary! To celebrate, we put together a comprehensive report on research findings, key accomplishments, and the future of AIS research – check it out here. As you’ll see, incremental steps are beginning to lead to big wins.
It’s been an exciting five years of research accomplishments, and we can’t wait to see what our researchers discover next. If you’re fired up by what we’ve accomplished in our first five years, show your support with a gift today. We need all hands on deck in this effort. Thank you!