Invasive species cause biodiversity loss and about $120 billion in annual damages in the U.S. alone. Despite plentiful evidence that invasive species can change food webs, how invaders disrupt food webs and native species over time has remained unclear.
American shad, a non-native fish species introduced to the Columbia River basin in the late 1800s, has replaced salmon and steelhead as the most abundant anadromous fish in the basin – by a long shot – and, although there are a number of uncertainties, their abundance could be impacting salmon and steelhead recovery in the Columbia and Snake rivers, a recent report says.
On Sunday, June 27, watercraft inspection stations in eastern Montana intercepted two boats entering the state carrying invasive mussels, making it the 35th and 36th mussel-fouled boats intercepted this year. This surpasses the total number of 35 mussel-fouled boats intercepted in 2020.
Biologists led by the University of Iowa discovered the presence of the invasive New Zealand mud snail by detecting their DNA in waters they were inhabiting incognito. The researchers employed a technique called environmental DNA to reveal the snails' existence, showing the method can be used to detect and control new, unknown incursions by the snail and other invasive species.
A draft report by the Pacific States Marine Fisheries Commission shows that funding for watercraft inspection stations in the four Northwest states in 2020 remained nearly the same as levels spent in 2019. However, interceptions of small watercraft infested with zebra or quagga mussels at the states’ borders rose by 15 percent.
The Oregon Department of Agriculture has filed emergency rules prohibiting the import of Marimo or moss balls infested with invasive zebra mussels.
On the heels of a successful and significant reduction of lake trout in Lake Pend Oreille, Idaho is now using some of the same methods – gillnetting and an angler rewards program – it used to fight lake trout in a new effort to reduce the population of invasive walleye in the lake.
Nearly 3,000 moss balls, which are suspected or confirmed to be contaminated with zebra mussels, have been seized or surrendered to British Columbia conservation officers as part of widespread efforts to stop the potential spread of the invasive species.
Some invasive species targeted for total eradication bounce back with a vengeance, especially in aquatic systems, finds a study led by the University of California, Davis.