Algae outbreak killing fish in Roosevelt Lake (AZ)

BrendenL

Junior Poster
Jul 2, 2012
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http://www.azcentral.com/news/artic...lga-outbreak-killing-fish-roosevelt-lake.html

A lake-wide golden algae outbreak is killing fish at Roosevelt Lake, said Arizona Game and Fish Department officials.

Golden algae produces a toxin that only affects gill-breathing animals. The threadfin shad and gizzard shad are susceptible to the golden algae's toxin, said Rory Aikens, Arizona Game and Fish Department Public Information Officer.

About 30 to 40 large decaying gizzard shad can be found throughout the lake on a regular basis, an Arizona Game and Fish Department press release stated. The threadfin shad, a smaller fish, is not as noticeable as the gizzard shad because birds are eating them.


There is no estimate of how many fish have died because birds and coyotes have been eating the fish, Aikens said.

There is a possibility the algae can spread downstream to other lakes or affect other species of fish.

Golden algae can be present for years and not cause any problems. Environmental factors make the algae go from dormant to active, Aikens said.

Apache, Canyon and Saguaro lakes had golden algae in the past and probably have some there now, Aikens said. There are no reported cases of fish dying at any of these lakes.

In July, thousands of fish died because of the golden algae in a 20-mile stretch of the Salt River, just upstream from Roosevelt Lake.

The reason why golden algae produces toxins and the origin of golden algae are still unknown.







Its been going on since July

http://www.kpho.com/story/18961599/wildlife-officials-blame-golden-alga-for-fish-die-off


PHOENIX (CBS5) -
Golden algae are believed to have caused a massive fish die-off on the Salt River upstream of Roosevelt Lake.

The Arizona Game and Fish Department officials said they began receiving reports of dead fish on Wednesday and went to the area Thursday morning to find out what happened.

Golden alga is a one-cell aquatic organism about the size of a human blood cell that releases toxins that affect gill-breathing aquatic organisms, mainly fish and clams, according to the Arizona Game and Fish website. The toxins cause fish gills to bleed internally and lose their ability to exchange water and absorb oxygen. Fish then die of asphyxiation.

The toxins have no apparent lethal or harmful effects on humans or animals that do not breathe through gills.

"The team is taking water quality samples and examining the dead fish to determine a cause as soon as possible," spokesman Kirk Young said.

Young said initial reports are that the die-off has been fairly extensive, with the number of dead fish estimated anywhere from hundreds to thousands.

Young said it appears to have impacted a variety of species including catfish, carp, bluegill, red shiner and buffalo fish.

"At this point, the fish kill seems to be confined to an area of the Salt River upstream of Roosevelt Lake. So far, we have not found any fish dying in Roosevelt Lake itself," Young said.

The department believes drought conditions and high salinity create an environment where the alga can grow.

Biologists think the alga will not become a problem in Roosevelt lake because the river mixes with the lake water, which dilutes the salinity.

Authorities advise people to not eat any dead or dying fish they find anywhere, regardless of the cause.

Game and Fish will continue to investigate and monitor water ways along the Salt River, including Apache, Canyon and Saquaro lakes where the alga is believed to exist but is less concentrated.