Stellwagen Bank sits like a wall at the edge of Massachusetts Bay, forcing water from the Gulf of Maine and waters inside the Bay around its edges and over its surface. The sanctuary's seafloor is consists of a variety of habitat types found across the Gulf of Maine. (Computer image by USGS)

At times the surface of the sea can be like glass, smooth and uninterrupted by breaking waves. Here, a humpback whale (Megaptera noveangliae) click image for more...(photo: AnneSmrcina)

Atlantic herring (Clupea harengus) is one of the marine fish species not considered overexploited. Large schools of these small fish are click image for more... (photo: Jon Witman)

A northern red anemone (Urticina felina) sits atop a boulder as an American lobster (Homarus americanus) pears out from below. Deep boulder reefs provide shelter for a large number of species. (photo: Dann Blackwood and Page Valentine, USGS)

Frilled anemones (Metridium senile) share a boulder with numerous other encrusting animals. The deep boulder reefs of northern waters can be just as click image for more... (photo: Dann Blackwood and Page Valentine, USGS)

These sponges (Polymastia sp.) sit in a constant current that brings a ready supply of food. The rock and click image for more.... (photo: Dann Blackwood and Page Valentine, USGS)

Encrusting sponges and coralline algae coat parts of this cobble field. Other animals seek shelter in the nooks and crannies. (photo: Dann Blackwood and Page Valentine, USGS)

A sea scallop (Placopecten magellanicus) sits alone in a gravel field. Rock and gravel substrates are click image for more.... (photo: Dann Blackwood and Page Valentine, USGS)

As can be deduced from their names, the sand lance (Ammodytes americanus) and sand dollar click image for more... (photo: Dann Blackwood and Page Valentine, USGS)

A field of live sand dollars (Echinarachnius parma) sits on a sandy plain along with one test (the white inner structural form from a dead sand dollar). (photo: Dann Blackwood and Page Valentine, USGS)

A brightly colored horse star (Hippasteria phrygiana) sits on silty sand. Colorful sea stars are found all over the globe, including the Gulf of Maine. (photo: Dann Blackwood and Page Valentine, USGS)

A sponge forest (Isodyctia sp.) on a sandy stretch of the bank provides shelter for a longhorn sculpin. click image for more... (photo: Peter Auster and Paul Donaldson, NURC, UConn)

Shell piles collect in troughs between sand waves on the top of Stellwagen Bank. Some animals find shelter between the shells. (photo: Dann Blackwood and Page Valentine, USGS)

Fan worms (Myxicola infundibulum) build mucus tubes into the mud and then spread their gills to catch floating plankton and detritus, while a Pandallid shrimp comes out from hiding under a sponge (Iophon sp.). (photo: Dann Blackwood and Page Valentine, USGS)

A collection of sea stars (Asterias vulgaris) gives a "starry night" effect to this muddy basin area in the sanctuary. (photo: Dann Blackwood and Page Valentine, USGS)

Cerianthids (Cerianthus borealis) dig their columns into the mud. Looking somewhat like palm trees, these click image for more... (photo: Peter Auster and Paul Donaldson, NURC, UConn)

These holes in the mud of Stellwagen Basin may be the homes of American lobsters (Homarus americanus) or click image for more... (photo: Peter Auster and Paul Donaldson, NURC, UConn)

A smooth sun star sits on the muddy sea floor, looking much like a child's drawing of the sun in the sky. (photo: Dann Blackwood and Page Valentine, USGS)