Fall is a good time to check for invasive species on aquatic gear

This is the time of year when lake property owners are spending time taking out their piers, swim rafts, and other equipment that has been in the lake since spring. It is time to get things winterized and cleaned up to be put back in next spring. It is also a good time to do a quick check for any possible aquatic invasive species (AIS).

Aquatic invasive species such as spiny waterflea and zebra mussels may be found in the fall while taking out the dock or swim raft. Spiny waterflea, individually, are small enough that a person would not normally see them. However, they tend to collect on thing such as fishing line, anchor ropes or other lines such as that which have been in the water for an extended time. They gather together and form a somewhat gelatinous looking mass, which is quite visible. Spiny waterflea has already affected a couple of our Northwoods lakes, including Trout Lake and Ike Walton Lake.

Spiny waterflea is an invasive waterflea that likely came to the United States in ballast water of large ships and has since found its way to inland lakes. They prey on native zooplankton, meaning less food for native fingerling fish. They outcompete native species for resources and disrupt food webs. It has been said, if eaten by young fish, they can accumulate in the digestive system of fish with their spiny tail causing damage to the internal organs of the fish. Anyone finding spiny waterflea on a lake not known to have that invasive species should call the Department of Natural Resources (DNR) and report the finding.

Zebra mussels, too, can attach themselves to piers, shore stations and even boat props that have been in the water all season long. These will be very easy to see if they are on equipment. Most native mussel species will not be found attached to rocks and equipment. Instead they burrow into the sediment where they filter water, potentially removing harmful bacteria. Native mussels play an important role in aquatic ecosystems. Invasive mussels disrupt this role by outcompeting native mussels. Again, anyone finding what they think to be zebra mussels on boats, docks or swim platforms when removing them at the end of the season should inform the DNR of their finding.

Other AIS such as curly leaf pond weed (CLP) and Euraisan water milfoil (EWM) may also be found at this time of the year when pulling things from the lake. It is always a good idea to check each piece of equipment after removing it from the lake. The best case scenario is a property owner does not find any new invasive species. However, if a new species is found, and it is caught early, there is a better chance of staying on top of it and keeping it under control, or perhaps even eradicating it. Landowners who find a suspected invasive species can have it identified by the DNR or through the county land and water conservation department. It can be kept in a plastic bag or container with some water until such time as it can be brought in to be properly identified. It is also a good idea to contact the lake organization, if the lake has one, to let them know about the finding.

Spending a few minutes inspecting equipment as it comes out of the lake at the end of the season can go a long way toward keeping the water healthy. For those in Oneida County, the land and water conservation department can be reached at 715-369-7835. In Vilas County, the department can be reached at 715-479-3747.

Beckie Gaskill may be reached via email at [email protected].