There’s an abundance of freshwater leeches in New Melones Reservoir this year, prompting health officials to remind the public that the annoying bloodsuckers pose little threat to humans.
It’s typical for leeches to appear in the lake during the warm summer months, but the unusual amount this year has taken many by surprise, according to Pete Lucero, spokesman for the U.S. Bureau of Reclamation, which runs the New Melones Dam.
“Conditions this year we’re kind of ripe for them to have a bonus production year,” Lucero said.
He said higher than average water storage in the reservoir combined with the hot temperatures has multiplied the number of leeches lurking in the muddy waters near the shorelines.
Carryover storage from near record-high snowpacks following an unusually wet 2010-2011 winter season helped the reservoir weather this year’s dry season.
According to monthly storage reports, there was about 1.7 million acre-feet of water in the reservoir on July 1. On the same date in 2011, the storage was recorded at about 2.3 million acre-feet because of the heavy winter precipitation.
But the years prior to that when there was less leech activity are a different story.
The reservoir storage was only about 1.4 million acre-feet of water in 2010, and nearly 1.3 million in 2009.
Roughly two acre-feet is enough water to fill one Olympic-sized swimming pool.
“We’re not doing anything to get rid of them,” Lucero said of the leeches. “They’re harmless.”
Lucero said it’s been months since there have been any complaints about leeches, which he attributes partially to a flier the Calaveras County Public Health Department posted around the lake in June.
The flier states freshwater leeches like those found in New Melones are very small, easily removable and don’t carry any diseases.
Lucero said leeches he’s seen this year have been as small as a grain of rice.
The flier instructs visitors to remove a leech by firmly sliding their finger toward the end of the leech as its feeding and use their fingernails to push the end sideways away from skin, which will detach the leech’s suction.
It also advises potential victims to clean the area where the leech was attached with soap and water.
People who wish to prevent contact with leeches are advised to simply avoid swimming.