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New Report Documents Importance of Shallow-Water Bottom Habitats in the Gulf of Maine

Who Typically Uses What?

Vegetated Habitats
(eelgrass and macroalgae)
Juvenile lobsters, cod, tomcod,
pollock, cunner, red hake, white hake,
tautog, and winter flounder use this
habitat to hide from predators.
Eelgrass. Photo Credit: NOAA Fisheries, Sue Tuxbury

Gravel Habitats
Mussels, juvenile lobsters and juvenile cod are common in intertidal and sub-tidal gravel habitats. Intertidal mussel bed.
Photo credit: NOAA Fisheries, Mike Johnson

Mud and Sand Habitats
Smooth flounder and winter flounder use these habitats as juvenile nursery grounds and deposit their eggs on the bottom.
Soft-shell clams and sand lance burrow into the bottom. Winter flounder in Narragansett Bay. Photo credit: NOAA Fisheries, Jerry Prezioso

Rocky Habitats
Mussels, juvenile cod and lobsters, as well as tautogs are often found in boulder habitats. Sub-Tidal rocky habitat.
Photo credit: NOAA Fisheries, Mike Johnson

By Dr. David K. Stevenson, Greater Atlantic Regional Fisheries Office, Habitat Conservation Division

Shallow water marine and estuarine habitats have been identified as Essential Fish Habitat for many species important to commercial and recreational fishermen in the greater Atlantic region of the U.S. These habitats are highly productive because of their shallow depth, seasonally warm water temperatures, and proximity to the land and the nutrients that are derived from river runoff. They serve as nursery grounds for juvenile fish which, in turn, provide food for larger fish. Many fish and invertebrate species also mature and reproduce in shallow coastal waters. However since they are close to the coast, shallow-water habitats are also vulnerable to habitat degradation and loss resulting from a variety of human activities.

In an effort to evaluate the importance of various types of shallow-water habitats in the Gulf of Maine, the Habitat Conservation Division of NOAA’s Greater Atlantic Regional Fisheries Office has recently completed a report. The report summarizes what is known about the functional value (for survival, growth to maturity, and reproduction) of eight different types of habitat for sixteen fish and invertebrate species.

The species that were selected included some federally-managed species, some species that are managed by the states, and some non-managed species that are important members of the inshore marine ecosystem. Habitat use was assessed for the various life stages of each species in the following benthic (bottom) habitats: mud, sand, gravel/cobble, boulder, eelgrass, macroalgae, salt marsh channels, and shell beds.

Habitat use scores (1 = present, 2 = common) were assigned to each benthic life stage known to occur in depths less than 10 meters and then summarized for all species in each habitat type. The evaluation was based on a review of approximately 125 publications in scientific journals. In cases where information was lacking, scores were based on best professional judgment. Detailed summaries for each species are presented in an appendix to the report.

The results support the fact that shallow water habitats in the Gulf of Maine provide valuable ecological benefits for a variety of commercially-important species. The top ranking habitats – those where species were either “common” or “present,” were: 1) sand and gravel/cobble; 2) mud, eelgrass and macroalgae; 3) boulders and salt marsh channels; and 4) shell (mussel) beds. However, for species and life stages that were considered to be common, vegetated (eelgrass and macroalgae growing on rocky substrates), sand, and gravel habitats ranked higher than the other four types.

Some species, like cod and lobsters, move into deeper water as they get older, while others like mussels, clams, windowpane and smooth flounders, and cunner are restricted to shallow water for their entire lives. Species like winter flounder, smooth flounder, sand lance, clams, cunner, mussels, and clams spawn in shallow water.

Click here to view the report.

How Will the Report be Used?
The information in this report will be used by NOAA Fisheries to make more effective habitat conservation recommendations for projects and activities that could potentially adversely impact essential fish habitat for NOAA trust resources in coastal waters of the Gulf of Maine. The chart below identifies some common species in eight shallow-water Gulf of Maine habitats.  it also indicates the total number of life stages that are found in each habitat type (juv=juvenile, j/a=juvenile and adult).

Mud Sand Gravel Boulder Eel Grass Macroalgae Marsh Channels Shell Beds
Smooth flounder j/a Little skate j/a Atl cod juv Blue mussels j/a Atl cod juv Am lobster juv American eel juv Blue mussels j/a
Softshell clams j/a Sand lance j/a Am lobster juv Tautog juv Atl tomcod juv Cunner j/a White hake juv Tautog juv
Winter flounder juv Softshell clams j/a Blue mussels j/a Am lobster juv Pollock juv Pollock juv Winter flounder juv  
  Windowpane j/a Little skate j/a Atlantic cod juv Red hake juv Red hake juv    
  Winter flounder juv Sand lance adult   Tautog j/a Tautog j/a    
        White hake juv White hake juv    
        Winter flounder juv      
5 9 7 5 8 8 3 3