Invasive Pests to Worry About Before HABs Strike in Late Summer (Clean Your Boat’s Hull Before Launching)

ITHACA, June 8, 2021 — The peak season for harmful algal blooms, or HABs, is at least two months away, but the Finger Lakes have plenty of other pests and invasive species to worry about before toxic algae takes center stage.


The Catharine Creek and Keuka Outlet tributaries are being treated this month with chemicals to combat sea lampreys, the blood-sucking, eel-like creatures that attach themselves to trout and kill them.

In April, a city block in Ithaca was closed so crews could remove trees infested with the invasive spotted lantern fly, which gorges on grapes, apples and hops as well as maple and walnut trees.

Many Finger Lakes marinas are washing and disinfecting the bottoms of boats to stop the spread of hydrilla (at right), “the Godzilla” of invasive weeds. So far, Cayuga is the only one of the Finger Lakes that has reported  it — at spots near Ithaca and Aurora, among others — but all 10 others lakes are on the watch. The perennial plant forms dense stands that crowd out native species and clog waterways.

These and other biological invaders — mussels, weeds, insects, foreign  aquatics — disrupt recreation, tourism and fishing in the Finger Lakes. 

The state attempts to control them by means of a group of eight regional partnerships called PRISM (Partnerships for Regional Invasive Species Management). The state Department of Environmental Conservation designated the first full week in June as Invasive Species Awareness week

Last month DEC Commissioner Basil Seggos noted that boater traffic in New York increased by nearly 20 percent at some launches, and boat stewards saw 390,000 boats at launches across the state. 

“Aquatic invasive species like zebra mussels, spiny waterflea, hydrilla and others can be easily transported from one waterbody to another on boats, trailers, and fishing equipment,” Seggos said. 

The goal, he said, is to have boaters clean off their fishing tackle, remove aquatic vegetation from rudders, disinfect boat hulls and water compartments and properly dispose of their bait.

Hydrilla infestations alone in Cayuga, Erie, Tioga, Tompkins and Westchester counties are costing more than $1 million a year in control and mitigation, the DEC said.

The coordinator of the Finger Lakes PRISM, Hilary Mosher of the Finger Lakes Institute at Hobart and William Smith Colleges, said educating boaters and expanding watershed inspection steward programs are top priorities.

The 11 Finger Lakes are not all plagued by the same non-native species — although a few, like the zebra mussel and eurasian watermilfoil, are common to virtually all of them. 

Watermilfoil, with brown or green stems and tiny pink flowers, thrives in area with high nutrients (phosphorus, nitrogen, etc) and grows into dense mats.

The fishhook water flea has been found in Seneca, Keuka and Canandaigua, but not in the eastern or western lakes. Natives of the Black and Caspian seas, they cut the survival rate of young fish by outcompeting them for food.

The starry stonewort (at right) has been reported in Cayuga, Canandaigua, Keuka and Otisco lakes, but not in Seneca or Skaneateles. 

Water chestnut has been found in Cayuga, Canandaigua, Keuka and Otisco, but not in several other Finger Lakes.

For a breakdown of priority invasive species, lake by lake, see here.

The DEC notes that invasive species are able to reproduce at alarming rates because they don’t have to contend with predators, parasites and diseases that control their numbers in their native habitats — often Eurasia. 

“Some of these species were introduced into New York waters via ballast water discharges, as ships from ports around the world travel up the St. Lawrence Seaway and into the Great Lakes,” the DEC said. “Several invasive aquatic plants have been introduced through the home aquarium trade.”

Several fish diseases such as “whirling disease and viral hemorrhagic septicemia” have also reached New York. “Although these diseases are not a threat to human health, they can have dire consequences for our native fish communities,” the DEC said. 

Over the past several years, harmful algal blooms have been particularly alarming as they’ve spread through the nationwide, including New York State and all 11 Finger Lakes.

HABs are actually not algae, but rather cyanobacteria, which can produce dangerous toxins that threaten public water supplies. Generally, the blooms thrive in calm, warm water that is nutrient-rich. They peak in August, September and October.

1 Comment

  1. Hi Peter, And I thought I was moving down to the lake for the next months to relax😊. After reading your excellent article, and drinking some strong coffee, I am armed with my pitchfork, sun helmet and glasses prepared to do battle!😎

    Thanks, Ed😖

    On Tue, Jun 8, 2021 at 8:45 AM Water Front- Peter Mantius wrote:

    > Peter Mantius posted: ” ITHACA, June 8, 2021 — The peak season for harmful > algal blooms, or HABs, is at least two months away, but the Finger Lakes > have plenty of other pests and invasive species to worry about before toxic > algae takes center stage. T The Catharine Creek ” >


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