Harmful Algal Blooms (HABs) – Division of Water Monitoring and Standards logo

HABs Monitoring FAQs

A harmful algal bloom (HAB) is an algal bloom that can be dangerous to people, animals or the ecology. Some, but not all, HABs produce chemicals that can be toxic to humans and animals if ingested, inhaled, or if contacted by skin or mucous membranes. These toxins can also accumulate in fish and shellfish which can cause illness when either are consumed. HABs can occur in both the freshwater and marine water environments. For additional information on freshwater cyanobacterial HABs, please visit www.state.nj.us/dep/wms/bfbm/CyanoHABHome.html. For additional information on marine water-related HABs, please visit www.state.nj.us/dep/wms/bmw/phytoplankton.htm.

Human Health effects: Adverse health effects of cyanotoxins include allergic- like reactions (e.g.’ rhinitis, asthmas, eczema, and conjunctivitis), flu-like symptoms, gastroenteritis, respiratory irritation, skin rashes, and eye irritation. More serious adverse health effects may include liver toxicity and neurological effects. Studies in laboratory animals suggest the possible involvement of some cyanotoxins in tumor formation.

  • Sunlight
  • Slow-moving water
  • Nutrients (nitrogens and phosphorous)
  • Nutrients pollution from human activities makes the problem worse, leading to more severe blooms that occur more often.

No, many of the suspected HABs that are investigated are from reports submitted by the public, however there are DEP staff in the field doing routine monitoring on NJ’s lakes, rivers, and streams, as well as other partners (e.g. parks and local health depts) who may report suspected HABs. DEP also employs enhanced technology such as flight surveillance and continuous monitoring meters deployed at specific locations.

DEP has a new online tool, that can be accessed from either a smartphone or computer, to report a suspected HAB. The tool can be found here [Report a HAB].
DEP has also produced a training video for users who are unfamiliar with this tool, which can be found at [Training Video - Report] If no smartphone or computer are available, as a last resort, suspected HABs can be reported to the DEP Hotline (1-877-WARNDEP).

A feature of the new online reporting tool is the ability to upload photos of the suspected HAB. DEP scientists review the information supplied and, if the photos clearly indicate that it is something other than a potential HAB (e.g., duckweed), water samples are not collected. DEP’s HABs website features a collection of photos of HABs, as well as other blooms that resemble HABs but are not.
If photos are inconclusive DEP will deploy staff or partners to perform a site survey. This site survey will determine if a HAB may indeed be present and samples are necessary for lab analysis.
In addition, samples are generally not collected for lakes that reside on private property (e.g., as part of a homeowner’s property).

HABs that occur in the summer are likely to persist into the fall, and as previous data has shown, sometimes continuing over the winter. Once a HAB is confirmed, there is no reason for additional monitoring unless a partner, the public or remote sensing indicate there has been a change for better or worse. In addition, remote sensing, satellite imagery, phycocyanin meters and other tools allow us to more efficiently determine where HABs are occurring, their spatial extent and relative change. We ask partners (e.g. parks and local health depts) to visually surveil confirmed HABs and DEP also supplies some partners with phycocyanin meters for additional monitoring. DEP is continuing to expand the phycocyanin meter loan program to expand our HAB response network. A recreational bathing beach may be sampled on a more frequent basis. An appropriate alert is posted (both physically via signage as well as on the HAB Dashboard) to inform the public about appropriate precautions that are recommended.

DEP has developed an interactive mapping and communication system that allows users to see the results of all of the HAB-related sampling that has been performed by Bureau of Freshwater and Biological Monitoring staff. Users can view sampling conducted by date, a listing of all waterbodies that have been sampled to date, zoom in and out of a statewide map to target particular waterbodies of interest, as well as (by clicking on dots on the map) get results for each lake/waterbody that has been sampled. Colors of the dots represent the HAB Alert Level that matches the sample results. The interactive map is available here [Interactive Map].
A tutorial on using this map is available here [Training Video / Sampling]

DEP is currently using continuous monitoring buoys to monitor Lake Hopatcong and Manasquan Reservoir remotely. Data for both of these locations are available at http://njdep.rutgers.edu/continuous/. DEP is also purchasing an additional 10 buoys which will be placed, in Spring 2021, at various lakes with history of persistent and widespread HABs to assist the department in better understanding the factors contributing to these recurring blooms.
DEP also conducts lake flights every Tuesday ~ May-October, weather permitting. The flight covers Spruce Run, Round Valley, Budd Lake, Lake Hopatcong, Lake Mohawk, Lake Musconetcong, Swartswood Lake and Greenwood Lake. A hyper-spectral sensor is mounted to a NJ Forest Service Plan and is used to estimate algal activity. These data allow DEP to understand where HABs are occurring, the spatial extent and relative change.

As mentioned above, once a HAB is confirmed, there is no reason for additional monitoring unless a partner, the public or remote sensing indicate there has been a change for better or trending toward a higher alert tier. HABs that occur in the summer are likely to persist into the fall and sometimes continue over the winter. In addition, HABs are generally localized along a shoreline or within a cove due to currents and wind. Lake-wide HABs are an unusual occurrence and the Alert Levels, and recreation use recommendations, are for the immediate area where the HAB occurred. The rest of the waterbody can be used for recreation per normal local regulations. The public should be aware if there is a HAB on a waterbody and should avoid recreating in water that appears green or have a spilled-paint like appearance or surface scum.
Remember to “Avoid it and Report it”.