• Granite mountains on islands along coast

    Acadia

    National Park Maine

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  • Park Loop Road opening

    May 17, 2013: The entire Park Loop Road and all other paved roads in the park open today. All dirt roads in the park, including the Seal Cove Road, will open on June 3.

  • Trail closures

    April 22, 2013: The Precipice, Orange and Black, Valley Cove, and Jordan Cliffs Trails are closed until further notice because of nesting peregrine falcons. All other trails in the park are open, whether accessible from the park or from state roads.

  • Hulls Cove Visitor Center

    May 17, 2013: The visitor center will open on May 19 and will be open 9-5 every day. All park passes are available there. There is an accessible entrance at the back of the building for those who have trouble climbing stairs.

Field Guide to Marine Invertebrates - Mollusks

Periwinkle feeding on alga
Littorina littorea (gastropod)
Littorina littorea ("common periwinkle") is an introduced snail that is one of the most abundant and important herbivores in the intertidal zone. Littorinids are inactive in winter and become active when temperatures rise in spring.
 
Green-colored periwinkle feeding on alga
Littorina obtusata (gastropod)
Littorina obtusata ("smooth periwinkle") is often found in the mid-intertidal zone of Acadia National Park on Fucus vesiculosus and Ascophyllum nodosum. This herbivorous snail has a smooth shell but occurs in many colors (e.g., black, brown, yellow, and orange).
 
whelk_bak

Nucella lapillus (gastropod)
The shell of Nucella lapillus ("Atlantic dogwinkle," "dog whelk") varies in color from white to dark yellow, brown, or orange. The Atlantic dogwinkle is abundant in the low intertidal zone. Nucella commonly feeds on barnacles and mussels.

 
Five mussels on rock
Mytilus edulis (bivalve)
Mytilus edulis ("blue mussel") is a bivalve that attaches to rock by byssal threads. Blue mussels are filter feeders. During red tides, blue mussels feed on dinoflagellate algae containing saxitoxin in the phytoplankton. This makes the mussels unsafe to eat and causes closures of mussel beds to harvesting. Sea stars and crabs prey on mussels, restricting them to the mid- and upper intertidal zones. Larvae settle onto shores of Acadia National Park in autumn, when masses of young mussels can be observed on the rocky shore.
 
Limpets on algal crust
Tectura testudinalis (gastropod)
This limpet is an herbivore that feeds on algal crusts, including those of calcified red algae. It is found in tide pools and the lower intertidal zone. Young individuals are typically brown, but the shell is often worn and white in older animals.
 
Photos by Sarah Hall.

Did You Know?

From atop Cadillac Mountain, the sun is just starting to rise over the Porcupine Islands.

Cadillac Mountain in Acadia National Park is the tallest mountain along the eastern coast of the United States. During certain times of the year, it is the first place in the U.S. to see sunrise.