Stockdale Harbor is on the northwest coast of Montague Island in Prince William Sound, Alaska. The harbor was named in 1787 by Captain Nathaniel Portlock for his publisher John Stockdale.
The horizontal banding on the beaches in Stockdale Harbor results from the repeating types of marine plants and animals that live on the beach. These patterns are accentuated during the summer extreme low tides when the tidal range exceeds 16 feet (5 m) and most of the beach face is exposed. Intertidal plants and animals developed adaptations to tolerate a range of atmospheric and oceanic conditions. These adaptations have evolved to provide a competitive advantage for food, space, or sunlight. Many intertidal plants and animals are permanently attached to the rocks and can live only at certain elevations on the beach. They depend on the rise and fall of the tides for access to food or nutrients and protection from predators. Mobile animals such as sea stars, crabs, and fishes, will take advantage of the high tides to feed in the intertidal and then seek shelter in pools, crevices, or deeper water at low tide.
Intertidal communities may include dozens of different and sometimes codependent species uniquely adapted to a particular combination of environmental conditions. Studies have shown that these groups of plants and animals will develop repeating patterns when physical conditions are the same. Read more here and here. Explore more of Stockdale Harbor and Montague Island here: