Opalescent Nudibranch In The Sand

By -
Today we look back to August 3rd on the beach. Gina Palmer was the lead interpreter on the beach for the 1.4 ft low tide at 7:46pm. It was a sunny afternoon with a NNW winds between 15 and 25 knots. The opalescent nudibranches, typically found under the boulders in the central pools of Haystack Rock, were today out in the sand.


Opalescent Nudibranch 

The opalescent nudibranch (Hermissenda crassicornis) is an invertebrate that resides in the intertidal rocky shores from Baja California to Alaska. They grow to about 3 inches, subsisting on a diet mainly of hydroids, but will also eat small sea anemones and bryozoans.  A nudibranch lives for a maximum of one year and is hermaphroditic. It's eggs are laid in narrow, coiled strings attached to eelgrass or algae. 

The opalescents are a colorful species of nudibranch, having bright orange areas on their back with a blue line on each side. Next time you're in the intertidal zone at low tide - anywhere on the west coast -take a look in the sand or under boulders for these colorful invertebrates!

Comments

Post a Comment

Popular posts from this blog

Nudibranchs in the Tidepools

By -
Image
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 wit...
Read more

What Is That Foam?

By -
Image
Visitors to Haystack Rock were recently greeted with an intertidal covered with a brownish foam and, naturally, asked 'What is That Foam?' The foam has been prevalent up and down the north Oregon coast during the last week, evident both in the surf, on the beaches and in the intertidal zone. Sea Foam on Cannon Beach, Spring 2014 Photo Courtesy of Carolyn Propst The foam is not pollution but is created by microscopic phytoplankton. Phytoplankton are one-celled organisms that are at the bottom of the ocean's food chain. Diatoms are the most common form of phytoplankton on the north Oregon Coast. The phytoplanktons contain a fatty-like material, called cytoplasm, that holds them together. When the phytoplanktons die, the cytoplasm 'glue' the individual skeletons together. This creates layers that trap air within the ocean water, increasing the surface tension and creating the bubbles. When there are a lot of phytoplankton more of them die creating even more ...
Read more