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DMWR advises no swimming or fishing in Pago Harbor

Cause of algal bloom in Pago Pago harbor still unknown
blue@samoanews.com

Results of tests conducted on the tissues of the dead fish that was discovered in the Pago Pago Harbor area in August and brought to the Department of Marine and Wildlife Resources (DMWR) are inconclusive.
 
According to DMWR fisheries biologist Alice Lawrence, “A fish was seen swimming erratically upside down in the inner harbor area on August 22 and was later found dead and brought to the DMWR office.” The fish was 45cm long and identified as Plectropomus maculates, a spotted coral grouper or Gatala. Tissue samples were sent to the USGS National Wildlife Health Center in Hawaii and the results have come back ‘inconclusive’.
 
Lawrence said scientists in Hawaii who conducted the test couldn’t pinpoint exactly what caused the fish to die, as the fish was determined to be a healthy one.
 
The dead fish was thought to be connected to the current conditions of the Pago Pago Harbor— an algal bloom which has caused discoloration of the water in the bay area, from dark brown and reddish brown to tan in some areas.
 
“A DMWR investigation of the harbor water revealed an abundance of a microscopic algae known to form large blooms. It turns the water brown red and later black brown, which is similar to what is happening in the inner harbor,” Lawrence told Samoa News yesterday. “The harbor water also showed high levels of phosphate.”
 
Reports of fish swimming upside down and swimmers suffering boils and respiratory problems have been connected to the algae bloom, according to Lawrence.
 
But how this started is still unknown.
 
Experimental tests in China showed that a bloom can kill shellfish populations but is usually considered harmless to other organisms at higher levels of the food chain.
 
The most recent local algal blooms were recorded in 2007 and 2009 in Pago Pago Harbor, which Dr. Morton ascribed to the dinoflagellate Ceratium furca. Those algal blooms, according to Lawrence, were thought to be caused by an excess of nitrogen fertilizer from an unconfirmed source near the harbor head.
 
Late last week, four dead pufferfish were reported in the Pago Pago area but “the fish were too old to send samples for testing,” Lawrence explained.
 
She urges the public to contact the DMWR hotline directly at 633-4456 to report any dead fish, turtle, or any other dead creature so they can send samples off island for analysis.
 
“The tissue needs to be fresh,” she said.
 
Meanwhile, recent discussions with harbor users have resulted in reports of a school of Mullet (or Agae) also swimming upside down near the DMWR marina dock.
 
Lawrence said there is reason to believe that a specific pollution incident may have caused this recent bloom, potentially as far back as the end of August. 
 
Until further notice, the DMWR recommends that the public stop swimming and fishing in the harbor area.



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