The Day • 9/12/2013
Stonington – With the increasing presence of invasive species such as Japanese shrimp and sea squirts and signs of declining water quality, continued monitoring of conditions in the Mystic River has perhaps never been more important.
That was one of the messages conveyed by speakers at the annual meeting of the nonprofit environmental group CUSH – Clean Up Sound and Harbors – at Mystic Seaport Wednesday.
“We’re seeing these drops in water quality in 2012, and it could be a simple blip, or it could be the wave of the future,” Claire Gavin, director of the group’s water quality testing program, said during her presentation, addressing an audience of about 50. “The only way to find out is to keep testing.”
Gavin, the fifth and final speaker of the event, said the group began its testing of five sites on the Mystic River in 2009, with volunteers trained by the University of Rhode Island in methods “to establish a scientifically credible water quality database” that would inform efforts to clean up the river. The group tested for dissolved oxygen, salinity, temperature, pH, algae, nitrogen and phosphorous levels – measures of the health of the river and factors interfering with its ability to support marine life.
“The cleanest sites are closest to the coast,” she said. “The dirtiest ones are the heads of long, narrow coves. Where flow is poor, the water quality is poor.”
Using the Aquatic Health Index that takes data averaged over several months to rank water quality as good, fair or poor, the sampling rated Ram’s Point at the mouth of the river as good, Murphy’s Point to the north as fair to poor, and Mystic River Park as fair to poor, with both Murphy’s Point and Mystic River Park sites dropping in quality from 2011 to 2012, Gavin said. Data for this year have not yet been compiled into rankings.
Water quality was rated as fair at two additional sites: Beebe Cove and the seaport.
James Carlton, professor of marine sciences and biology at Williams College and director of the Williams College-Mystic Seaport Maritime Studies Program, said a phenomenon known as “Caribbean creep” is bringing more warm-water species north.
Warming waters due to climate change, coupled with the continued introduction of non-native species from Europe, Asia and elsewhere are playing “ecological roulette” on the habitats of tidal estuaries such as Mystic River, he said.
Since arriving in the 1990s, the Japanese shore crab has become the most abundant crab species throughout southern New England, he said. Several kinds of sea squirts from Asia and Europe and Japanese shrimp are now in the Mystic River. New non-native species of barnacles and sea anemone have been found there in the last month, he said.
“And shipworms are becoming much more abundant, because of the warming waters,” he said, showing a slide photograph of a piece of wood coursed by dozens of tunnels bored by these destructive creatures, a species of saltwater clam.
The good news, Carlton said, is that there is now widespread awareness of invasive species and the damage they can do to habitats, along with increasing actions to control new invasions.
“We’re paying much more attention than ever before to these changes, and there are more efforts to control the vectors that are bringing in these new species, and doing more to keep our fingers on the pulse of change,” he said.
