Herald Staff Report


TRENTON –The Department of Environmental Protection on Friday lifted harmful algal bloom advisories for additional areas of Lake Hopatcong, bringing to about 60 percent the total area of the lake no longer under advisory.


DEP monitoring indicates that cell counts for cyanobacteria, the organism causing the blooms, have fallen below the state’s Health Advisory Guidance level at the mouth of Wood Port Bay, east of Davis Cove Mid-Lake and the Bertrand Island area.


Areas that remain under advisory are the mid-lake area in the lower-central portion of the lake, the Prospect Point and Wood Port Bay area in the northeastern arm of the lake, the Crescent Cove/River Styx Area, and the area adjacent to Hopatcong State Park. Recreational users are reminded to avoid swimming or coming in contact with lake water in these areas until monitoring demonstrates that cell counts fall below the Health Advisory Guidance level.


Harmful algal blooms are not caused by true algae but are caused by bacteria that in many ways resemble and behave like algae. The causes of the Lake Hopatcong bloom this summer are not fully understood. However, harmful algal blooms are generally fueled by nutrient-laden stormwater runoff followed by periods of hot weather that cause the proliferation of these bacteria, which are naturally present in waterbodies.


Under these conditions, blooms can reach levels that can be harmful to people and to pets coming in contact with the water. They typically subside with the onset of cooler weather.


Often referred to as blue-green algae, harmful algal blooms form dense mats, often appearing as pea soup or spilled paint. The DEP advises the public to avoid swimming and water sports that may result in contact with water in impacted areas or in areas where they suspect a bloom may be occurring. These activities include jet-skiing, water-skiing, canoeing or kayaking.