Showing posts from June, 2015

Nudibranchs in the Tidepools

Nudibranchs, also referred to as sea slugs, can frequently be spotted in the tidepools at Haystack Rock. There are many species of nudibranch, most having outstanding markings and colors. The nudibranch feed on bryozoans, hydroids and sponges and it's color can be changed by the food it eats.   The nudibranch has a pair of sensory projections on their head, called rhinophores, which allow them to smell and taste. Virtually all nudibranchs have some form of eyes but they are not well developed and in most cases are little more than a pigment spot in the head near the rhinophores.  The nudibranch breathes through gill projections which extract oxygen from the seawater. The Pacific Northwest has more than 200 species of nudibranchs.

The Opalescent Nudibranch (Hermissenda crassicornis) could be called 'showy'. It is found from Alaska to Baja, California and can grow to two inches in size. At Haystack Rock, it can be found in the sandy bottom of a tidepool. It is slender with n…

Tracks in the Tidepools

Hermit Crabs have curved abdomens which are soft, unlike most crustaceans which have hard, calcified abdomens. Because of their soft abdomens, the hermit crab is vulnerable to predators and seeks protection in the form of salvaged, empty seashells. The hermit crab will typically select the shell of a sea snail into which its entire body can retract for protection.

Hermit Grab in the Tidepool Photo Courtesy of Carolyn Propst
As you might guess, as a hermit crab grows it gets too big for its salvaged shell and must look for a larger one. The competition for shells can be vigorous when there are lots of hermit crabs of the same size vying for an available shell. When the hermit crab finds a new shell it will leave its current shell to 'try on' the new shell. If it fits, it will stay in the new shell leaving the old shell for a smaller hermit crab to make the shell its home. If it doesn't fit, the hermit crab returns to its shell and continues the quest for a empty shell that …

Black Oystercatchers Need Your Help!

The birds continue to be active at Haystack Rock. Today, the Black Oystercatchers take center stage! Oystercatchers have been seen mating and are nesting on the Rock.

The Black Oystercatcher (Haematopus bachmani) is a large (about the size of a crow) and noisy bird that makes its home along rocky shores from Alaska to Baja California. It is a wading bird, black in color, with a long, red bill, yellow eyes that are outlined in red, and tan colored legs. They feed primarily on mussels, limpets and other shellfish; foraging mostly near low tide and resting at high tide.  When feeding on mussels, found in abundance on Haystack Rock during low tide, the bird either finds a slight opening in the shell, inserting its long, red bill into the opening to feed or the bird will hammer on the shell to open it.

Black Oystercatcher, August 2014 Photo Courtesy of Susan Glarum
The Oystercatcher nests well above the high tide line and near a food source such as mussel beds. The nest site is typically o…