A new study from Montana State University has revealed how invasive species can disrupt native food webs in lakes. The study, published in the journal Ecosphere, found that invasive mussels and zooplankton can significantly reduce the amount of food available to native fish, leading to population declines.

The study was conducted in Flathead Lake, a large lake in northwestern Montana. Flathead Lake is home to a variety of native fish species, including bull trout, kokanee salmon, and lake trout. In recent years, the lake has been invaded by two non-native species: quagga mussels and Daphnia zooplankton.

Quagga mussels are small, fingernail-sized mussels that can reproduce rapidly and colonize large areas of the lake bottom. They filter feed on algae and other small organisms, which can reduce the amount of food available to native fish. Daphnia are small, planktonic crustaceans that feed on algae and other small organisms. They can also reproduce rapidly and can reach high densities in the lake.

The study found that both quagga mussels and Daphnia can significantly reduce the amount of food available to native fish. In areas of the lake where quagga mussels were present, the biomass of native zooplankton was reduced by 50%. In areas where Daphnia were present, the biomass of native zooplankton was reduced by 30%.

The reduction in food availability can lead to population declines in native fish. In Flathead Lake, the population of bull trout has declined by 50% since the introduction of quagga mussels and Daphnia. The population of kokanee salmon has declined by 30%.

The study provides evidence that invasive species can disrupt native food webs and lead to population declines in native fish. This information can be used to develop management strategies to control invasive species and protect native fish populations.

Key Findings:

* Invasive mussels and zooplankton can significantly reduce the amount of food available to native fish, leading to population declines.

* In Flathead Lake, the population of bull trout has declined by 50% since the introduction of quagga mussels and Daphnia.

* The population of kokanee salmon has declined by 30%.

* This information can be used to develop management strategies to control invasive species and protect native fish populations.