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Warmer temperatures in the United States’ deepest lake may explain the growth of a crayfish population that now threatens the lake’s long-time resident, the Mazama newt, and other wildlife. Oregon’s Crater Lake, formed nearly 8,000 years ago after the eruption of Mt. Mazama, is the only place in the world where the Mazama newt thrived for thousands of years. In 1915, early conservationists introduced crayfish as a food source for the lake’s game fish. “That turned out to be a worse decision than stocking the fish in the first place, because the crayfish have become out of control,” said Park Superintendent Craig Ackerman. Crayfish and newts compete for the same food sources and studies show the crayfish harasses the defenseless newts, causing them to flee areas of their shoreline habitat. By 2014, the crayfish had taken over 75 percent of the lake’s shallow waters and have contributed to the depletion of the lake’s other species, including snails and other small organisms. The lake’s beautiful crystal blue color could diminish with fewer small organisms around to eat algae. Crater Lake biologist Scott Girdner believes that climate change is playing a role in the surge of the crayfish. The lake’s warmer temperatures allow crayfish to move faster, Girdner said. The National Park Service is considering several options, including underwater fences. If the crayfish can’t be slowed down, the newts may be exiled to natural spring-fed pools or “newt nurseries” found around the edges of the lake. Crayfish are unable to reach the pools, making them ideal for newt breeding.Vocab
invasive species
— a plant, fungus or animal species that is not native to a specific location and which has a tendency to spread and sometimes damage to the surrounding environment
caldera
— a large volcanic crater, typically one formed by a major eruption leading to the collapse of the mouth of the volcano
biodiversity
— the variety of life in the world or in a particular habitat or ecosystem
Warm up questions
- What is a natural habitat? What are some habitats in our community?
- What happens when a new species of plant or animal is introduced to a habitat?
- To what extent is it humans’ responsibility to protect endangered species from extinction?
Critical thinking questions
- Why is the Mazama newt unique and why is it vulnerable to extinction at the moment?
- What should be done to control Crater Lake’s crayfish population?
- Are invasive species always introduced intentionally? What other examples of invasive species have you heard of where you live?
