• Views from Penobscot Mountain summit.

    Acadia

    National Park Maine

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  • Temporary Road Closure

    A section of the Western Mtn Road in Southwest Harbor will be closed until 8/18 while park crews replace a culvert with a new fish-friendly open bottom culvert. For more information and a map visit our Getting Around Page. More »

  • Trail Closure: Gorge Path weekdays, 7 am - 4 pm

    The section of the Gorge Path between the Hemlock Path intersection and the A. Murray Young Trail intersection is closed until rehabilitation work is completed. The closure will be in effect Mondays through Fridays only, from 7 am to 4 pm.

Field Guide to Marine Invertebrates - Echinoderms

Northern Sea Star
Asterias rubens
Asterias rubens ("northern sea star") can be purple, reddish brown, orange, or yellow. It commonly feeds on blue mussels, restricting their lower range on the shore.
 
Green sea urchin in habitat
Strongylocentrotus droebachiensis
Strongylocentrotus droebachiensis ("green sea urchin") is found in the lower intertidal zone in tide pools and is abundant in the subtidal zone. In a natural cycle, large groups of urchins eat their way through kelp beds to create “urchin barrens” where seaweeds are scarce; then, the urchin population decreases because of lack of food, allowing the kelp beds to recover. Recent overfishing of urchins on the Maine coast caused notable increases in kelp populations near the shore.
 
Photos by Sarah Hall.

Did You Know?

A girl stands along the stone steps of the Kurt Diederich Path in this historic image taken around 1920.

Acadia National Park contains more than 120 miles of historic hiking trails. Many of these trails were established by local village improvement societies in the late 1800s and early 1900s. Today many of the historic features, such as stonework, are still visible.