Reddish-brown patches in the water of Gastineau Channel as seen from the Douglas Bridge on Tuesday, July 31, 2018. (Michael Penn | Juneau Empire)

Reddish-brown patches in the water of Gastineau Channel as seen from the Douglas Bridge on Tuesday, July 31, 2018. (Michael Penn | Juneau Empire)

Possible algae increase dyeing Gastineau Channel waters red

No reason to believe it’s dangerous, scientists say

Eric Prestegard saw it for the first time Sunday.

A shade of rust-colored red crept its way through the waters of Gastineau Channel as Prestegard, the executive director of Douglas Island Pink and Chum (DIPAC) Inc. watched and worried. This is a vital time of year for the hatchery, which is midway through its egg taking process, Prestegard said.

Two days prior to that, the Alaska Department of Environmental Conservation had gotten a call that something unusual was floating around in the channel. Dave Pikul, an environmental program specialist for the Southeast Region’s Spill Response Unit, went down to the water and took a look.

“It was pretty widespread,” Pikul said. “Our observations down at the shoreline identified it was not oil, but it was some kind of biological mass.”

Exactly what that biological mass is, however, is still yet to be determined. Kate Kanouse, a habitat biologist for the Department of Fish & Game, said the overriding current theory is that it’s an algae bloom, or algal bloom. An algae bloom is a rapid increase in the amount of algae in the water, usually brought on as a result of rising water temperatures.

“That’s the most likely cause,” Kanouse said. “We’ve had a nice warm summer and it fits the criteria of what we would see of an algal bloom. I wouldn’t expect it to be anything else, and I don’t expect it to be dangerous.”

Algae blooms can be harmful, but not all of them are, according to the National Ocean Service. Vera Trainer, a research oceanographer with Northwest Fisheries Science Center, said blooms can cause a lack of oxygen in the water, which can kill small fish. More commonly in Alaska, she said, blooms affect shellfish.

“The most common in Alaska that are known of right now are the paralytic shellfish poisoning events that are resulting in accumulation of toxins in shellfish that can then be dangerous to humans,” Trainer said.

Trainer said algae blooms in Alaska are old news, as Aleuts have known about toxic shellfish for generations. Trainer said people should pay attention to health authorities’ websites and announcements about shellfish.

For many in Juneau, the reddish hue of the water is a new sight. Prestegard said he can’t remember a time when algae or phytoplankton were this widespread, even in the hot summer of 2004.

As he’s watched from his spot along the channel, Prestegard said that so far, everything seems to be fine.

“We’ve observed it the last three days,” Prestegard said. “At this point, it doesn’t seem to be affecting our fish in any way, shape or form.”

Prestegard said they’re a bit concerned about their aquariums, though. While the fish seem to be holding up well, DIPAC employees aren’t certain that smaller animals will be so immune. Prestegard said the algae bloom — or whatever it might end up being — has not made its way right up to the hatchery quite yet, but they’re watching closely.

Trainer said blooms will likely become more and more common in Alaska as ocean temperatures continue to rise. As ice melts, she said, sunlight will penetrate the water easier and promote more growth among plant life such as algae.

“Certainly with warming water,” Trainer said, “there’s going to be a larger suite of algal bloom problems that can occur in Alaska.”


• Contact reporter Alex McCarthy at 523-2271 or amccarthy@juneauempire.com. Follow him on Twitter at @akmccarthy.


More in News

A Princess Cruise Line ship is docked in Juneau on Aug. 25, 2021. (Michael Lockett / Juneau Empire File)
Ships in Port for the week of June 26

Here’s what to expect this week.

Former President Donald Trump speaks at the Road to Majority conference Friday, June 17, 2022, in Nashville, Tenn. A rally planned to include Trump is scheduled to happen in Anchorage on July 9.  (AP Photo / Mark Humphrey File)
Trump to rally for Palin, Dunleavy, Tshibaka in Anchorage

Former President Donald Trump plans to attend a rally in Alaska next week.

It's a police car until you look closely and see the details don't quite match. (Juneau Empire File / Michael Penn)
Police calls for Thursday, June 30, 2022

This report contains public information from law enforcement and public safety agencies.

Courtesy Photo / Office of Gov. Mike Dunleavy 
Gov. Mike Dunleavy on Tuesday signed the budget for the upcoming fiscal year.
Gov. Dunleavy signs budget

PFD of about $3,200, $400 million in vetoes to Legislature-approved items among declared highlights

It's a police car until you look closely and see the details don't quite match. (Juneau Empire File / Michael Penn)
Police calls for Wednesday, June 29, 2022

This report contains public information from law enforcement and public safety agencies.

The Alaska Department of Health And Social Services building in Juneau has no visible signs indicating the department is splitting into two agencies as of Friday. Top officials at the department said many of the changes, both physical and in services, are likely weeks and in some cases months away. (Mark Sabbatini / Juneau Empire)
Little sign of big change for DHSS

No commissioner at new department, other Dept. of Health and Social Services changes may take months

Elizabeth Peratrovich Hall, 320 W. Willoughby Ave., will be open as a cooling center through Wednesday for elders who need a cool place during the ongoing heatwave. (Michael S. Lockett / Juneau Empire)
Tlingit and Haida opens cooling center for elders

Keep your cool during the heatwave.

An Alaska Seaplanes Cessna 208A, seen here on the tarmac, suffered damage after failing to achieve takeoff near Elfin Cove on Sunday, June 26, 2022. (Courtesy photo / Alaska Seaplanes)
No one hurt after plane’s takeoff goes awry

The aircraft failed to achieve take off and hit the beach while leaving Elfin Cove.

A 13-year-old girl was medevaced Saturday after being struck by a vehicle near the crosswalk across Egan Drive by Gold Creek. (Michael S. Lockett / Juneau Empire)
Teen in serious condition after SUV strikes bike

Juneau Police Department is investigating.

Most Read