Know your beach-this week from the beach

#2 in the 2017 series of guest blog posts by Seattle Aquarium beach naturalists Bobby Arispe and Jen Strongin.

I am so excited for my second year of being a beach naturalist and the chance to keep blogging for the Seattle Aquarium. My first shift of the season was at Dash Point State Park in Federal Way. This is the most southern beach our naturalists cover. Dash Point is a unique beach for our team for a couple reasons:

  1. It is a state park so the rules are a little different. There were lots of dogs on the beach and lots of families out harvesting shellfish (more on that shortly).
  2. It is all sand. No rock shelves or boulders for sea creatures to hide on. This meant we had to look for the smaller creatures and the ones that live under the sand.
Dash Point’s wide sandy beach

Dash Point’s wide sandy beach

It was Memorial Day weekend and the sun was out. The park was absolutely packed with families out enjoying the warm temperatures and blue skies. Our naturalist team hit the beach and we had no shortage of curious kids and families. Since I knew I was not going to find any sea stars or anemones I focused my attention onto the moon snail egg collars. These gray, rubbery, plunger-looking things that most people think are washed-up trash are actually made by the large moon snails that love sandy areas like the ones at Dash Point. The egg collars not only hold millions of moon snail eggs, they also serve as homes and dinner for a variety of tiny creatures. When you find a moon snail egg collar, gently turn it over, keeping it very close the ground. There are often a variety of sea slugs and snails underneath. One of the creatures that I was finding under almost every other collar was a type of sea slug called an opalescent nudibranch. This gastropod is one of the favorites of beach naturalists. They can grow up to three inches long. They are a beautifully shimmery, almost translucent pearl color with brilliant orange tips on their feathery cerata (the part that helps them breathe). They also can have bright teal streaks along their body and their horn-like rhinophores just add to the adorable factor.

Unique opalescent nudibranches:

unique opalescent nudibranches collage 1unique opalescent nudibranches collage 2

Since shellfish harvesting is allowed at this state park (check this URL), we got the rare chance to see massive horse clams (Pacific gaper) and geoducks out of their sandy homes below the surface. We generally only get to see their siphons sticking a few inches out of the sand, filtering water in and out as they eat. The geoducks were so fascinating to see—they are huge! Their body and shell can be to three to four feet below ground, and their long siphon can still reach up to the surface to feed. Watching the families work as a team to get these mollusks from their deep homes was really interesting, and I was exhausted just watching them.

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One last unique feature of Dash Point’s beach is a massive sand dollar aggregation. This area is filled with thousands of eccentric sand dollars. The purple ones are alive, covered in dense, tiny spines. They can live for up to 10 years, and what we often find on the beach is the white exoskeleton after they have died.

Eccentric sand dollar aggregation

Eccentric sand dollar aggregation

A live Eccentric sand dollar makes its way deeper into the sand

A live Eccentric sand dollar makes its way deeper into the sand

Meet Seattle Aquarium beach naturalists on local shorelines this summer! Check our website for dates, times, locations and directions.

About Bobby:

This is Bobby’s second year as a beach naturalist.

His passion for the Salish Sea started when he and his wife moved to Seattle four years ago from San Antonio, Texas.

Bobby is an avid photographer and enjoys capturing his adventures of the Pacific Northwest. During the week you will find him biking to work where he leads a creative team at a local marketing agency.

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One Response to Know your beach-this week from the beach

  1. kc dignan says:

    That was very interesting and informative. It was nicely written, especially for someone who is not familiar with the area or the topic. Thank you.

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