Twenty-six salmon pools on the Miramichi River have been closed to all fishing because of warm weather, Fisheries and Oceans Canada says.

Because of high water temperatures and low water levels, the federal department has had to adopt a warm-water protocol in recent years to protect fish until the water cools down, says the president of the Miramichi Salmon Association.

"The water warms up, the salmon congregate at the mouth of cold-water brooks, and they sometimes get in very shallow water and are very exposed," Mark Hambrook said.

The cold-water pools are found at the junction of warmer waterways, such as rivers and brooks, throughout the Miramichi River system.

Hambrook said the temporary closures can happen any time in the summer if temperatures rise. 

Sometimes, if the water temperature stays above 23 C for 48 straight hours, recreational fishing is only allowed between 5 a.m. and 11 a.m., when the water is cooler.

Miramichi river

The closure of the Miramichi salmon pools is temporary and will be lifted when the water cools down. (Contributed by Bryn Robinson)

Hambrook said temperatures are expected to drop this weekend, making a long closure unnecessary.

"We don't expect this one to last long," he said. "By the first of the week, it should be open again, and depending on how our summer goes, it could happen again."

Salmon under stress

Warm water can be harmful to salmon, he said.

"Once the temperature gets above 23 degrees [Celsius] then the fish are under stress. They build up lactic acid in their blood, and it's only when the temperature cools down that they are able to get rid of that and perform normal body functions."

He said it would not be sporting if anglers went after the fish when they are already lethargic because of the warmer water.

There is almost no point fishing in extremely warm temperatures anyway, he said, because fish won't bite.

"It's a local impact for people that happen to own cold-water pools and want to go fishing, it's certainly going to be a hardship for them," he said.

Anglers follow catch-and-release rules, meaning a caught fish must be released back into the water. Hambrook said if an angler does catch a fish in extremely warm temperatures, it could die.

"Sometimes you just have to do what's best for the fish," he said.