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Skip Navigation LinksDNREC : Division of Watershed Stewardship : Shoreline and Waterway Management

Macroalgae in Delaware's Inland Bays


The water quality of Delaware’s Inland Bays is very important to outdoor recreational activities available for Delawareans and visitors alike. The Assawoman, Indian River and Rehoboth Bays provide a superb venue for fishing, boating, waterskiing and other related outdoor activities. However, like so many natural resources, these areas also suffer from the negative effects of development and other land-disturbing activities.Macroalgae harvester snapshot

With development and runoff from adjacent residential and agriculture lands, there has been an increase in nutrients deposited in these water ways, which has resulted in an increase in macroalgae growth. Attached macroalgae are beneficial in that they provide habitat for juvenile crabs and fish. When the algae become detached and begin to accumulate along shorelines and in near-shore areas, these buildups then become both environmental and nuisance concerns. For this reason, the DNREC Macroalgae Harvesting Team, under the direction of the Division of Watershed Stewardship, initiates harvesting activities to remove these problem buildups. One of the goals of these activities is to minimize the amount of by-catch present in the accumulated algae. For this reason, the Division of Watershed Stewardship coordinates its harvesting operations with the Division of Fish & Wildlife to ensure that the amount of by-catch is minimized to the extent possible.

The Harvesting Program began in 1997 and typically operates from early April through August in any given year. The Harvesting Team routinely conducts weekly inspections throughout the Inland Bays to locate potential or known problem areas for harvesting. With as many residents and annual visitors utilizing our Inland Bay waterways each year, this Program is a valuable asset in DNREC’s efforts to protect, preserve, and restore the natural resources of this estuarine environment.

Macroalgae Harvesting Program- identifying the problem
Algae is commonly divided into two categories; macroscopic (can be seen by human eye) and microscopic (can not be seen by human eye). Macroscopic algae are often referred to as macroalgae, or seaweed. The following types of macroalgae are the most commonly harvested algae species in Delaware’s Inland Bays.

Please use the following pictures to identify which type of algae you are dealing with before submitting an algae complaint. This information is very helpful to the Macroalgae Harvesting Team in their effort to eliminate the nuisance of excessive algae accumulation.



Common Name: Sea Lettuce
Scientific Name: Ulva lactusa
Description: Green algae that is sheet-like, thin, and very hardy. This type of algae emits a pungent odor when decomposing. 


Common name: Spaghetti algae
Scientific Name: Chaetomorpha spiralis
Description: Filamentous green/brown algae that grows in large compact balls.


Common Name: Hollow Green Weed
Scientific Name: Enteromorpha flexuosa
Description: Green algae that usually grows 3 – 8 inches tall and is composed of hollow tubes. 


Common Name: Red Weed, or Red Algae
Scientific Name: Agardhiella tenera
Description: Coarsely bushy red algae with rounded branches tapering at base that can grow to a height of 1 foot tall.


Macroalgae Harvesting Team Contact Information
Please contact DNREC's Macroalgae Harvesting Team by emailing or of the Division of Watershed Stewardship Shoreline & Waterway Management Section. In order to ensure that your request is handled as quickly as possible, we require that you include your name, email address and daytime telephone number. DNREC will respond within two business days. If you are reporting an algae bloom and have GPS coordinates, please include them in the comments section. Sending incomplete information will delay the Macroalgae Harvesting Team's response.

You may also submit information by mail to:

Macroalgae Harvesting Team
Shoreline and Waterway Services Facility
901 Pilottown Road
Lewes, DE 19958

or by phone: 302-855-7290




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