Yellowstone National Park will temporarily ban wakeboard boats and plans to gate boat launches this season to reduce the risk of introducing new invasive species in park waters.
About 25 people in flannel button-downs and puffy vests attended one of several planned public meetings about the changes in Bozeman Monday. Drew MacDonald, a fisheries technician, discussed Yellowstone National Park’s efforts to prevent aquatic invasive species.
“One of the big threats we’re worried about in Yellowstone National Park right now are zebra mussels. They are on the boundary; there’s a potential they can come in here,” MacDonald says.
Yellowstone Park staff inspected over 4,000 watercraft last year. Around 150 were deemed extremely high risk and went through a full decontamination.
“We’re doing an intense watercraft inspection here in the Park. Basically, we’ve started to put gates up so that people can only get in after we have done an inspection. From 8 a.m. to 4:30 p.m. you have to come to the backcountry office. We do the boat inspection and then that’s when you’re allowed to get out on the water,” MacDonald says.
The boating and fishing season in Yellowstone opens Memorial Day Weekend. Last week, Yellowstone announced a temporary ban on watercraft with internal ballast tanks. The Park did not indicate how long the ban would last.
“Basically they would be ski boats that have internal ballast tanks that we can’t see anddecontaminate easily. So we are going to put a halt to that until we can make sure everything’s going to be safe for us with the zebra mussels,” MacDonald says.
Invasive species are a top concern for the Park. It spends $2 million each year just to fight non-native lake trout in Yellowstone Lake. New research shows lake trout disrupt a complex food chain from zooplankton to elk.
“The problem with lake trout is they can grow very large. They can get to 100 pounds. They can live to 60 years of age and as they get larger, they feed on other fish,” says YNP biologist Phil Doepke.
An adult lake trout will eat approximately 42 native Yellowstone cutthroats a year. Park Service staff have removed over 3 million lake trout to date, primarily with a robust gillnetting program. They’ve reduced adult lake trout by 70 percent since 2012. But Doepke says gillnets will not be able to remove all of the lake trout, especially the smaller ones.
“So we’re doing other research, trying to find other ways of removing lake trout from the system, and what we’re mainly focusing on are ways of destroying the eggs, the lake trout embryos on their spawning sites,” says Doepke.
The team inserted transmitters into some of the lake trout to track them. The ‘Judas’ fish helped the researchers identify 14 spawning sites. Over the last few years, they’ve experimented with electrical grids, suction dredging, chemical applications and shredded lake trout carcasses, which smother the eggs.
Doepke says dropping fish carcasses on the spawning sites has proved to be highly successful. But since there will be fewer carcasses available as lake trout numbers decrease from gillnetting, the Park is also experimenting with organic pellets made from soy and wheat. Doepke says they are carefully studying whether this nutrient influx would affect the lake’s ecology.
The Montana legislature recently passed a bill requiring all ballast-style boats to undergo a mandatory decontamination when entering the state or crossing into the Columbia River Basin. House Bill 608 awaits Governor Steve Bullock's consideration.
Yellowstone National Park will host outreach meetings on fish restoration projects and fishing/boating regulations at 7:00 pm at the following locations:
- April 30 – West Yellowstone Visitor Center, West Yellowstone, MT
- May 7 – Cody Hotel, Cody, WY
- May 8 – Wort Hotel, Jackson, WY