All that the tides reveal: Puget Sound’s hidden intertidal world

We as Puget Sounders are able to enjoy many experiences and treasures in our region — things like temperate rainforests in the Olympic Peninsula, volcanic mountains that neighbor the sea, and some of the world’s most fertile farming lands paved by ancient glaciers and biblical floods.

But among the most special treasures, and maybe the most taken for granted, is the Puget Sound itself.

On June 15 and 16, beaches in our Puget Sound region had tides lower than any in the last 13 years. Thanks to the lunar nodal cycle, tides dropped more than 4 feet below the average tidal level.

Depending on the slope of the beach, a low tide of that magnitude revealed hundreds of feet of sea bed that can be explored without a wetsuit or a scuba respirator.

The Puget Sound is one of the most unique inland bodies of sea water anywhere in the world. The bedrock that props up its seabed was once carved out of ancient mountain peaks by giant Ice Age glaciers that long ago would have covered every major city in the region with thousands of feet of ice. The salty blue and green waters that we know as the Puget Sound is one of the most biologically diverse marine ecosystems in the world. It’s also a world famous scuba diving attraction for that reason.

Don’t be afraid to get wet

Have you ever walked on or driven by the shores of the Puget Sound and wondered what kind of otherworldly creatures were swimming, crawling, squirming, gliding, slithering, slinking, surviving and thriving just 30 yards away from the shoreline?

The Earth, the Moon, and the Sun have literally aligned to allow us terrestrial dwellers a rare peek into the underwater world. All you need to enjoy it is a pair of shoes that can get wet and a sense of child-like wonder.

On June 16, we explored the exposed sea beds off the shores of Dash Point State Park. As the peak of the low tide approached in the early afternoon, we slushed and tredged across hundreds of yards of sun-kissed sea bed to see what the tide would reveal.

We were not alone in our interest to explore the treasures of the intertidal zone. Many others combed the beach around us. Folks young and old craned their necks downward and scrutinized every rock, pool and sandbar, hoping to catch a glimpse of a sea creature, out of place and stranded by the sea’s tidal rhythm.

The beach at Dash Point was more sandy than rocky. There were very few boulders. In my experience tidepooling in the Pacific Northwest, boulders can typically turned over to reveal a community of sea critters using the rock and a tiny pool of water as shelter from the unforgiving sun.

In place of boulders, this beach had stretching beds of sea grass. The grass looked downtrodden and flattened outside of the water. Seagulls and herons picked through the grass at the edge of the receding shoreline, scouring the aquatic foliage for crabs and other invertebrates that were not quick enough to escape with the tide.

Along with plenty of crabs smaller than the size of a quarter, we found larger Dungeness crabs that died and were left to bake in the sun. We also found the molted exoskeletons of kelp crabs and what seemed like a never ending amount of clam shells, each one a relic of a life of a mollusk hunted by predators both marine and terrestrial.

One of those predators, and one of the top predators in the Puget Sound’s seagrass bed ecosystems, is the moon snail. They are gigantic mollusks larger than the size of the average fist. Their soft body is so large that it cascades out of their baseball-sized shell.

Despite their large size, they can be difficult to find because they burrow under the sand as the tide recedes, but evidence of them can be found strewn across the beach.

They feed on clams and shellfish by using a specialized drill-like tooth called a radula, which it uses to bore a hole through the hard shell of a clam or mussel so it can feed itself on the soft tissues protected inside. One can identify clams that have fallen victim to the moon snail by a very smoothly grinded hole on the shell.

Many beachgoers have probably noticed the moon snail egg collars left across the shore, but may not have known what they were. We found several dozen on our trip.

They are ring-shaped collars that are gray like the sand they are made of. The snail uses sand and a mucus excretion to form a structure to lay their eggs upon. To the touch, they feel smooth and waxy, almost like fruit leather.

The moon snail is one of many alien-like creatures that may be revealed by the changing Puget Sound tide, there are many different sea creatures to be seen, felt and discovered, but you may have to get your hands and feet dirty.