A brown tide that first began to develop in September has continued to increase into the fall months along Long Island’s south shore, scientists say. The alga’s development could have a significant impact on the future clam population as mature clams begin to prepare for mating season in the autumn months.
According to marine scientists the tide has impacted most of the Great South Bay, Moriches Bay and Shinnecock Bay, with particles reaching as high as 1,000,000 cells per milliliter as of Oct. 8. Any density higher than 50,000 cells could be harmful to clams and other marine life.
The water tests were conducted by experts from Stony Brook University’s Southampton Marine Science Research Center. According to the center, only the south shore’s inlet systems, including the New Inlet that helps flush Bellport Bay, has been spared the algae bloom, where cell counts were as low as 20,000 cells per milliliter. The center reported that this brown tide incursion follows a similar bloom earlier this summer. That has caused alarm for The Nature Conservancy (TNC), a group that works to restore hard clam populations on Long Island.
"We know from our experience in 2008-2009 that back to back brown tide blooms not only impacted survival and growth of young clams, it also impacted spawning of adult clams the following season,” Carl LoBue of TNC said in a statement. “We were encouraged in spring because conditions in central Great South Bay looked good into June, so this is disappointing.”
In the fall, mature clams go through a period known as “conditioning,” whereby the right food presented to them could foster reproduction. Brown tide alga, known as Aureococcus anophagefferens, could disrupt conditioning and the next generation of clams may fail. Scientists say the ultimate impact will depend on the tide’s length of stay.
Brown tide first appeared on Long Island waters in 1985. Researchers believe an increase in nitrogen in the water, combined with poor tidal flushing is the cause.