Concerned about aquatic invasive species that have popped up in other lakes across the country, Crater Lake National Park officials have temporarily closed the lake's pristine waters to scuba diving and other water gear uses.

Concerned about aquatic invasive species that have popped up in other lakes across the country, Crater Lake National Park officials have temporarily closed the lake's pristine waters to scuba diving and other water gear uses.

The immediate closure will remain in effect until protocols are established to minimize the risk of contamination from invasive species that include

quagga mussels and other species that could reduce the lake's world-renown clarity and purity, officials said.

The protocols, which will require divers to take precautionary measures before diving into the lake, are expected to be in place before the beginning of the 2013 season.

"We have seen the devastation to ecosystems and economies caused by the inadvertent introduction of invasive species from Lake Mead to Lake Erie," observed park superintendent Craig Ackerman.

"We want to prevent it from happening at Crater Lake rather than deal with the aftermath," he added. "The increasing popularity of the lake for scuba diving also increases the opportunities for divers and their gear to carry microscopic 'hitchhikers' into the water."

Although the invasive species may be small, the damage caused by introducing them into the lake is enormous and often irreversible, he noted.

In their native environments these species are often controlled by interactions with predators, parasites, pathogens, or competitors, he said.

However, when introduced to new environments such as Crater Lake, those natural checks are often absent, giving invasives an advantage over native species and making them very expensive and difficult to control, he said.

In addition to the quagga mussels, other aquatic invasive species that could threaten the lake include the spiny water flea, and the viral hemorrhagic septicemia virus which causes severe and permanent damage to the habitats they invade by reducing the abundance of native species and altering ecosystem processes, officials said. Those invasive species rank among the most severe threats to biological diversity in bodies of water, they add.

— Paul Fattig