Fishing bans imposed on drought-hit Washington state's

U.S. authorities banned fishing from Monday in most rivers and streams within the Olympic National Park in western Washington state, citing ongoing severe drought conditions that have harmed fish along the U.S. West Coast.

The emergency ban on Washington state's Olympic Peninsula imposed restrictions on recreational fishing on the Bogachiel, Sol Duc, Queets, and other rivers, as well as their tributaries in the Pacific Coastal area, the National Park Service said in a statement.

"Current conditions have made Pacific salmon, steelhead and bulltrout exceptionally vulnerable because of low stream flows and high water temperatures," Olympic National Park spokeswoman Barb Maynes said.

Monday's restrictions are the latest move by authorities working to protect native salmon and trout that have been suffering under excessive heat and drought conditions in the U.S. Northwest.

It's been so dry and hot in Washington that a wildfire is burning in an Olympic National Park rainforest and Governor Jay Inslee issued a statewide drought emergency in May as the snowpack in the mountains fell to historic lows.

Besides imposing fishing restrictions in Oregon and Washington state, officials have also trucked hatchery salmon more than a hundred miles (160 km) north to another facility, and American Indian tribes have sought to increase flows from dams.

Severe drought conditions this year have dropped water levels to historic lows, reducing the amount of space available for fish and leading to higher water temperatures that can weaken or kill Pacific salmon. 

Pacific salmon and trout suffer physiological stress at water temperatures above 60 degrees Fahrenheit (15.5 Celsius), with lethal effects beginning at 70 degrees (21 Celsius).

Temperatures higher than 60 degrees have already been observed in many Olympic Peninsula rivers, as have temperatures of 70 F in the lower Sol Duc and Dungeness Rivers, Maynes said.

Low water levels and high water temperatures can slow or even stop upstream salmon migration, and the fishing restrictions will help protect Pacific salmon, steelhead trout, and federally threatened bull trout, Maynes said.