Spring runoff throws wrench in plan to block non- native species.
Glacier N.P., Mont.- A plan to block non-native fish from one of Glacier National Park's purest lakes was washed out by excessive spring runoff.
Park officials designed a $20,000 barrier to stop non-native lake trout from replacing the west slope cutthroat trout and bull trout in the Quartz Creek drainage. Native fish have been dwindling at Glacier for decades, replaced by the non-natives that were deliberately introduced to the park in the early 1900s. Although Glacier received relatively high grades in NPCA's State of the Parks® report, invasive species were highlighted as a pressing threat.
Park officials planned to protect the native fish by installing the barrier to block non-natives from swimming up the drainage from the Flathead River.
But biologists from the Park Service and the U.S. Fish and Wildlife Service (USFWS), who visited the site in June, balked when they saw how much water was flowing down from the creek. Because of surprisingly strong runoff, they felt that a barrier would not handle the water flow, and that it may have washed away. They also believed that the non-native fish could go around the barrier at high water.
Superintendent Mick Holm said that although the project was canceled, the threat to the lakes -- and their fish -- remains.
"It is still agreed that under the right circumstances, non-native fish such as lake trout and rainbow trout would still be able to migrate into the upper Quartz drainage," he said. "Because of [that threat], we will continue to explore alternatives that may be used in the future to prevent fish migration up Quartz Creek without destroying the wilderness qualities of the area."
The Quartz Lake basin in the park's northwestern North Fork area is the last drainage that remains free of non-native fish, and Quartz Lake is one of the last in the Columbia River Basin still boasting all its native fish, said Deputy Park Superintendent Jerry O'Neal.
The lake's native bull trout are listed as "threatened" under the Endangered Species Act, and the west slope cutthroat is "a species of special concern," in Montana.
The park's plan called for large rock-filled cages across the stream, creating a four-foot waterfall. The thought was that the height of the fall would prevent lake trout and other non-native species from reaching the upper lakes. Funding for the barrier would have come, in part, from the Glacier Fund, a nonprofit that raises money for currently under-funded park projects.
Although park officials are not certain of their next step, they know that it must happen soon. In drainages adjacent to Quartz Creek, non-native lake trout are close to replacing bull trout. Since 1910, when Glacier became a national park, native fish populations have dwindled as non-natives prospered, in part because of a policy from the park's early days to stock non-natives.
"As a result, native fish began breeding with non-native fish-native west slope cutthroat trout bred with non-native Yellowstone cutthroat or rainbow trout," said O'Neal. "In more recent decades, the major impact on native fish has been from the invasion of non-native species through the Flathead River system into the lakes and streams of Glacier."
