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<b>AZ Game and Fish Department

<font color="green" size=+1>Fish kill mystery at 3 lakes has scientists playing detective</font></b>

May 21, 2004

PHOENIX – Perplexing fish die-offs at three lakes along the Salt River during the past two months have scientists and others playing detective.

There was a fish die-off at Apache Lake during March, one at Canyon Lake around April 27 and the latest was in Saguaro Lake May 5. Another die off was reported at Apache Lake on May 18. Authorities are actively investigating the die-offs.

Larry Riley, the fisheries chief for the Arizona Game and Fish Department, says department biologists are working closely with scientists from other agencies, experts from Salt River Project, and university scientists to solve the mystery.

“Despite collecting lots of samples in the field and running a barrage of tests, we can’t point a finger and say, ‘this is the definite culprit.’ Just like in the detective stories, however, we do have a primary suspect we are continuing to investigate: a strain of toxic blue green algae called Cylindrospermopsis Raciborskii,” Riley says.

Cylindrospermopsis is an algae that produces two toxins called cylindrospermopsin and anatoxin-a. “Those toxins can, in the right concentrations, cause fish die-offs. This is emerging as the most likely causative factor for the fish kills. Note that I said most likely factor – I cannot provide a smoking gun, but all the pieces of this puzzle seem to be fitting together,” Riley says.

Game and Fish biologists have worked with experts at the Arizona Department of Environmental Quality at the three lakes to measure dissolved oxygen in the water, pH (acidity or alkalinity), and temperature, and have also tested for evidence of hydrogen sulfide. “We have taken field measurements from one end of these lakes to the other. We have also inspected recently dead or dying fish for evidence of disease: nothing,” Riley says.

Scientists also collected water quality samples and plankton for laboratory analysis. “The water samples are being analyzed for a broad range of contaminants, which is a very time intensive process. We’re looking for a needle in the haystack, and the needle may not exist,” Riley says.

The department has also worked closely with the U.S. Forest Service on the issue. Tonto National Forest Supervisor Karl Siderits says campgrounds are still open and there are still plenty of fish to be taken in the three lakes.



<b>Arizona Department of Environmental Quality

Fish Kills Prompt Monitoring, Investigation at Salt River Reservoirs</b>

PHOENIX (May 21, 2004) -- ADEQ Director Steve Owens announced today that ADEQ is working with the Arizona Game and Fish Department, Arizona Department of Health Services, the Tonto National Forest, Salt River Project and the University of Arizona to assess and characterize the cause of recent fish kills that have occurred in Apache, Canyon and Saguaro Lakes.

Combined monitoring efforts by ADEQ, Arizona Game and Fish Department and the University of Arizona have confirmed the presence of potentially toxic algae within the lakes. The algae - Cylindrospermopsis raciborskii - have become dominant in Apache Lake and have been detected in other Valley reservoirs. The effects of the toxins are varied and can affect aquatic life, domestic animals, pets or humans that come into contact with the algae. The release of the toxins may occur within several hours to several days of coming into contact with the algae and can result in anything from mild stress to mortality in aquatic organisms. Symptoms in humans include mild skin irritation, nausea, vomiting or respiratory distress.

"We want to make sure that the public is fully informed about conditions at these lakes," Owens said. "People should not be overly concerned, but they should be careful to avoid contact with water in these lakes that is foamy."

ADEQ officials noted that additional samples are being taken and analyzed but to date, no toxins have been found in either the water or fish tissue. Until further notice, the public should observe the following guidance when recreating in and around the reservoirs:

Boaters and swimmers are advised to avoid contact with and ingestion of water in areas where the water is green-tinged or foamy. Particular attention should be given to children and pets, which may ingest large quantities of water.
The toxins produced by these algae do not appear to collect in fish tissue, but anglers should take a common-sense approach to eating fish caught from lakes. If the fish looks or smells unhealthy or was dead when caught, don't eat it. Fish caught should be thoroughly cleaned, gutted and cooked before eating.
This blue-green algae is a member of a group of algae that are commonly associated with summertime conditions - high temperatures, low wind, increased nutrient loadings. In Arizona, two factors may cause these early blooms - ongoing drought conditions prevent replenishing supplies of water from snowmelt and unusually high levels of nutrients brought into the lakes after the Rodeo-Chediski fire of 2002. Unlike other algae, Cylindrospermopsis does not form patches or scum on the surface, but rather forms in clumps or bands two to six feet below the surface. It generally forms in slow moving or still water and will cause the water to appear green-tinged or foamy.
 
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