October 04, 2007
The New York State Department of Environmental Conservation (DEC) today announced the presence of the invasive algae didymo in two additional fishing water bodies in New York State.
Samples taken by DEC have confirmed that didymo is present in the East Branch of the Delaware River. In addition, based on samples taken near the Route 191 bridge in Hancock, Delaware County, didymo is suspected to be present on the West Branch of the Delaware River as well. These are the latest recorded incidents of this aquatic nuisance species – also called “rock snot” – in New York State. Early this summer, didymo’s presence was confirmed in a section of the Batten Kill in Washington County.
The Delaware tailwaters are one of the premier trout fisheries on the East Coast, and are a popular destination for large numbers of anglers. The discovery of didymo in these waters is particularly troubling given their proximity to other famous trout streams, notably the Beaver Kill and Willowemoc Creek, and the tendency of anglers to fish multiple streams over the course of a day or weekend. The microscopic algae – an invasive species to New York – can survive for many days in cool, damp conditions. Porous materials such as neoprene waders and felt soles used by wading anglers are prime suspects in the spread of didymo among streams.
Didymo cells can produce large amounts of stalk material that forms thick mats on stream bottoms. The appearance of these mats has been compared to brown shag carpet, fiberglass insulation, or tissue paper. During blooms these mats may completely cover long stretches of stream beds and persist for months. The stalk material produced by didymo is slow to break down and may persist for up to two months following its peak growth. These mats alter stream conditions, choking out many of the organisms that live on the stream bottom, potentially causing a ripple effect up the food chain affecting trout and other fish.
Didymo has historically been limited to cold, nutrient-poor, northern waters, but in recent decades has been expanding its range and its tolerance to warmer and more productive streams. Once introduced to an area, didymo can rapidly spread to nearby streams. Anglers, kayakers, canoeists, boaters and jet skiers can all unknowingly spread didymo by transporting the cells on boats and other gear. There are currently no known methods for controlling or eradicating didymo once it infests a water body.
For more information about didymo, including decontamination procedures, visit this link.