Life Below the Tideline
By Mareth Griffith, Expedition Guide
This week, the Safari Explorer took advantage of an extremely low tide to prowl the shorelines of Frederick Sound in search of intertidal animal life. While Southeast Alaska experiences two low tides a day, the lowest of the low tides are reserved for the days immediately around the new and full moon. For a few short hours, marine creatures like anemones and starfish, who may only be out of the water only two or three times every month, are visible to anyone who is willing to do a bit of scrambling among the rocks to reach them.
When Sarah, our expedition leader, announced we’d be heading out to explore the beach at 7 AM in the morning, some folks looked dubious that the trip would be worth waking up that early. After dinner, I shared videos of some of the animals we’d be looking for - sunflower sea stars hunting the smaller, more agile brittle star, or the gaping, five-toothed mouth of the green sea urchin. That preview, as well as the promise of a hearty brunch when we returned, seemed to pique most of our passengers’ interest for what we might find on the beach as the tide dropped to one of its lowest levels of the month.
We stepped ashore the next morning under overcast skies, alighting onto a large grey beach, already covered by the spiny silhouettes of sea urchins half-buried in sand and concealing draperies of kelp. The beach itself appeared as descending terraces of dark, jagged stone covered with acorn barnacles and blue mussels. All along the beach, we saw quick squirts of water, spurting a few feet in the air, a testament to the clams burrowed among the sand and kelp. The empty shells of dead clams carpeted the lower areas of the beach, many of them providing cover for hermit and Dungeness crabs. Small kelp crabs, a species known for encouraging algae to grow on their backs as camouflage, flitted cautiously around the larger crabs. Some guests decided to imitate the crab’s decorating tendencies, and posed with the kelp crabs adorning their coat sleeves and hats…
The first starfish, wrapped snugly below a protective ledge of rock, were sighted, with many guests dipping their hands into the water and gently stroking the knobby backs of the starfish’s arms. Further searching among the rock ledges turned up anemones - their jelly-like bodies dangling off the rock walls, or crumpled into amorphous blobs. Alaskan anemones, while still capable of stinging powerfully enough to entrap small fish, aren’t potent enough to penetrate human skin. With care, it’s possible to gently touch the tentacles and feel a slight stickiness, as the anemone harmlessly fires its stinging cells. Other animals we found included several intact sea urchin shells - frail, hollow spheres onto which the body plan of a starfish can faintly be seen - as well as several species of a slug-like group of animals called chitons, and a tiny opalescent nudibranch.
My favorite find of the entire morning was a half-dozen sunflower sea stars. This was an animal whose predatory skills I mentioned the night before, and it’s particularly encouraging to see this species because they were hit hard by a condition known as Sea Star Wasting Syndrome. Now widespread on the Pacific coast, this poorly-understood phenomenon has been affecting sea star populations, especially the sunflower sea star. Seeing healthy sunflower sea stars on the beach here is a good sign that these animals - previously a candidate as a threatened species under the Endangered Species Act - may be making a comeback.
Though I doubt any of our passengers this week had sea stars or anemones on their bucket list of must-see Alaskan wildlife, everyone seemed enchanted with the number and variety of life we were seeing everywhere on the beach, from the massive, arm-waving sea stars to tiny, perfectly spiral whelk shells. Walking on a beach during low tide is a good reminder of how much life awaits us along the shorelines and coasts here in Southeast Alaska.