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Finding Fish Habitat: There’s a Map for That

By Dave Stevenson, Habitat Conservation Division

Say you are in charge of a town with an eroding beach. You want to bring in 500,000 cubic yards of sand to rebuild your beach. Where are you going to get the sand?

When the town of Winthrop, Massachusetts wanted to rebuild their beach, they requested a permit from the U.S. Army Corps of Engineers to get sand and gravel from an offshore site in Massachusetts Bay. After consulting with NOAA, the Army Corps denied the permit. The area happened to be “essential fish habitat” for 26 species of fish, including the much-prized Atlantic cod. With NOAA Habitat Conservation’s help, the Army Corps was able to point Winthrop to another source of sand that would not harm fish populations.

Every year, NOAA’s regional fisheries offices advise federal agencies on hundreds of projects, including the dredging of harbors, the filling of wetlands, the production of offshore energy, and fishing. These consultations ensure that projects funded by your tax dollars do not unwittingly damage “essential” marine habitats.

By the Numbers
$214 billion: Value of U.S. fishing industry
1.83 million: Number of American jobs in the fishing industry
1,000: Number of aquatic species with EFH identified
800 million acres: Amount of habitat protected under EFH authorities 

But, how does anyone know where the essential fish habitat (EFH) is?

It’s All about Location, Location, Location

This real estate mantra also applies to fish, shellfish, and other underwater creatures. Some species, like winter flounder, spawn in shallow waters with temperatures under 50°F. Others, like red crabs, spawn in depths of 200-1800 meters. Some fish need certain salinities or bottom cover, like gravel or cobble, to spawn, breed, feed, or grow (Figure 1).

The more of these small fish that survive to adulthood, the larger the populations of fish that will be available to sustain our fisheries..

Two small cod on gravel bottom
Figure 1: Two juvenile cod two inches long on a gravel bottom on Georges Bank. Photo used with permission from Page Valentine, USGS.

EFH Mapper: The Best Habitat Protection Tool You’ve Never Heard Of

To build our EFH Mapper, we first figured out where the essential fish habitats are through surveys. Then, we found out what the important parts of the habitat are – for one fish, it may be the silty bottom, while for another, the salinity or depth may be the key—and how the habitat feature could be affected by human activity. We worked with partners like the regional fishery management councils to use the best available scientific information to identify, describe, and map EFH.

Anyone who wants to do a project in the marine environment that may require a federal permit can see and download data for EFH maps. The maps also link to written descriptions for all the species and life stages managed in any of the seven NOAA Fisheries regions of the U.S. (Figure 2).

Map showing in pink the location of essential fish habitat for juvenile mackerel

Figure 2: EFH Map for juvenile Atlantic mackerel:

EFH text description for juvenile Atlantic mackerel:

Pelagic habitats in inshore estuaries and coastal bays from Passamaquoddy Bay and Penobscot Bay, Maine to the Hudson River, in the Gulf of Maine, and on the continental shelf from Georges Bank to Cape Hatteras, North Carolina, generally in depths between 10 and 110 meters and in water temperatures of 5 to 20°C. Juvenile Atlantic mackerel feed primarily on small crustaceans, larval fish, and other pelagic organisms.


One of the most useful features of the Mapper is a Location Query that allows a user to “drop a pin” on a specific location. The Mapper brings up a table listing all the species and life stages that are mapped at that location with descriptions for each one (Figure 3).

In the Greater Atlantic Region, our staff in the Habitat Conservation Division are continually updating the Mapper. The New England and Mid-Atlantic Fishery Management Councils provide information for updates to the EFH maps and text descriptions for the 37 species that they manage. We are also adding features to make it more useful to the public, such as more information on coastlines and estuaries, where salt water extends inland for miles.

A map with a pin in it showing how you can drop a pin on a map to find EFH
Figure 3: A location query in Chesapeake Bay.

Species and life stages at the location shown above:

Chart showing which species exist at the pinned location on previous map

Please contact David.Stevenson@noaa.govwith any questions about the EFH Mapper in the Greater Atlantic Region.