Hydrilla, super evil of the invasive plant world, is spreading

Posted on: April 18, 2018 | Bob Frye | Comments

Hydrilla can cause many problem for anglers and boaters.

Hydrilla, an aquatic invasive species, is spreading across America.

Hydrilla is a plant named for Hydra, the nine-headed serpent of Greek mythology, so that tells you something right there.

Simply put, it’s tough to deal with.

More and more people – including anglers and boaters – are going to find that out going forward.

It arrived in the United States from Asia in the mid-20th century via the aquarium trade and is now found in at least 30 states nationwide, according to the U.S. Fish and Wildlife Service. And the list is growing.

Often confused with a couple of native species, hydrilla has small, bright green, pointed leaves arranged in five whorls, give or take, connected directly to the stem. Stems can grow at a rate of one inch per day.

The weed grows not only vertically, but horizontally, too, from the surface down as deep as 20 feet.

“The stuff is incredible. It can grow deeper than any other aquatic plant. It can grow in less light. It can use fewer nutrients and it has a colder temperature range it will tolerate,” said Bob Morgan, lead aquatic invasive species ecologist with the Pennsylvania Fish and Boat Commission.

In the process, it forms massive, dense mats. They often get so thick that neither boaters nor anglers can penetrate them.

Hydrilla grows in thick patches.

This isn’t a picture of a field. It’s Lake Okeechobee, covered by a dense mat of hydrilla.

Indeed, in Florida – ground zero for the plant in many ways – there are actually lakes where “we have to cuts trails through the hydrilla so boaters can get to the main part of the lake,” said Jon Fury, the Pittsburgh native who serves as deputy director of the division of freshwater fisheries management for the Florida Fish and Wildlife Conservation Commission.

It’s no wonder the U.S Department of Agriculture’s Natural Resources Conservation Service includes it on its “noxious weeds” list, reserved for species that can’t legally be imported or even transported between states.

New York’s Department of Environmental Conservation even prohibits its sale or possession with that state. Other states, like Ohio, warn those who enjoy being on the water to be on the lookout for it.

Such rules haven’t kept it from showing up in new places, though.

In Pennsylvania, for example, as recently as 2000, it existed in just four counties statewide, Morgan said. Today it’s in about a third of the state.

It was most recently discovered in late 2017 in the Shenango River, downstream of Pymatuning Lake. That potentially theatens some pretty good fisheries.

“So it is spreading quite rapidly in this state. And it’s making us more than a little nervous,” Morgan said.

The reason is its impact on rivers, lakes and streams.

“The main takeaway about hydrilla is that it is an extremely aggressive, competitive aquatic plant,” Morgan said. “It has highly evolved behaviors or strategies that allow it to out-compete just about any other plant out there in the aquatic environment.”

The problem is, once it shows up in a waterway, it’s usually there forever.

It can reproduce in several ways. Most notably, if a boat motor plowing through a weedy patch chops it up, the pieces take root.

“That limits our management of the plant because it pretty much eliminates mechanical harvesting,” Morgan said.

Chemical treatment is an option. That’s what Florida relies on primarily.

But even that has limitations, Fury said.

Hydrilla is not favored by some fish species.

Hydrilla is very difficult to eradicate once established.

“I am sure there are some who would tell you that you can eradicate it out of systems. I’m more in the camp of, once it gets established, it’s very hard to eradicate,” Fury said. “You end up living with it and trying to figure out the best ways to manage it.”

That’s the tact Florida is taking these days. The state’s Department of Environmental Protection led the battle agaisnt the plant prior to 2008. Its mandate, Fury said, was to reduce the plant to the “lowest feasible level.”

The state spent $223 million between 1980 and 2010 trying.

That didn’t work.

“We’ll never get rid of hydrilla in Florida,” Fury said.

So, since 2008, the Fish and Wildlife Conservation Commission has managed hydrilla on a case by case basis.

If it shows up in a lake where it’s never been before, it tries to eliminate it, Fury said. If it’s already established, though, the agency simply deals with it as best it can.

And it’s not all bad, he added.

While panfish do not do well around hydrilla, some other species, notably largemouth bass, do. Anglers, in fact, often seek out the plant to find fish, Fury said.

Waterfowlers like it because it attracts ducks, too.

“Even though it’s an invasive plant, and we’d rather have native plants instead, it does provide some positive fish and wildlife benefits in some instances,” Fury said.

Morgan, though, would like to stop it in its tracks in Pennsylvania. Calling it “the super menace, the super evil of the aquatic plant world,” he said preventing its spread is critical.

“We’ve got to stop it in this state. We absolutely must,” Morgan said. “Our whole mission in this agency is in jeopardy from this stuff.”

Fighting hydrilla for agencies, anglers and boaters

When it comes to battling hydrilla on a large scale, resources are a problem.

New York will spend about $13 million battling invasive species this year, $3.5 million of that on aquatic invasives alone.

Other states, like Pennsylvania, can’t match that. And that’s a problem, agreed Fred Strathmeyer, chairman of the Governor’s Invasive Species Council of Pennsylvania.

“The answer is, we’ve really got to engage the legislature. We’ve got to engage the citizens,” Strathmeyer said.

The Fish and Boat Commission, council and others need to showcase not only the ecological damage that could result from invasives, but the economic damage as well, he added.

Time is of the essence, said commission ecologist Bob Morgan. The plant moves quickly.

Long Pond in Wayne County is an 80-acre lake. Hydrilla showed up there just a few years ago. It now covers nearly half of it, he aid.

Money aside, anglers and boaters can help stop the spread of the plant.

The New York Department of Environmental Conservation has a whole page devoted to hydrilla. It recommends they take these steps when moving from water to water:

  • Inspect and remove plant fragments and mud from boats, trailers, and equipment before and after each use.
  • Dispose of all debris in trash cans or above the waterline on dry land. That includes mud. Tubers and turions move in sediment.
  • Clean and dry your equipment thoroughly before visiting other waterbodies.
  • Do not dispose of unwanted aquarium plants in waterbodies, ditches, or canals.
  • Monitor recently acquired aquatic plants because hydrilla tubers can be transported in the attached soil/growing material.

Those with home aquariums and the like can learn how to properly dispose of unwanted materials – so that they don’t impact environments – at the Habitattitude website.

Bob Frye is the everybodyadventures.com editor. Reach him at 412-838-5148 or bfrye@535mediallc.com. See other stories, blogs, videos and more at everybodyadventures.com.

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