Opinion

A nighttime outing reveals the wonder of life along Vashon’s shores

For nearly a year now, an organized group of dedicated volunteers has haunted the beaches of Vashon, peering at the undersides of stones, gently searching among blades of eelgrass and walking carefully across beds of bivalves — all in the hope of finding beautiful wildlife many of us so frequently overlook.

Our group comes from all walks of Vashon, with the shared goal of educating ourselves and others about the diverse communities on our beaches. We hope to not just raise awareness of names and habitat, but also to inspire conservation by providing a meaningful context with which to interact with the natural world. We call ourselves the Vashon Beach Naturalists, and you can meet us this Saturday at Tramp Harbor, where we will introduce you to some interesting intertidal creatures, and you can see firsthand how the beach comes alive at night.

Nighttime is a fantastic time to visit beach residents, some of whom are more active under the cover of darkness. Some sea stars, polychaete worms, chitons, iso-pods (think pill bug) and octopuses are found to move around the beach more in the dark hours than the light. Many other animals choose to mate and spawn in the night, when their predators may pose less of a risk. For example, on a nighttime beach walk two years ago, visitors to Tramp Harbor found mating kelp crab and many dogwinkle eggs coating the beach.

This year we hope our December beach walk will again allow us to observe the dogwinkles’ winter laying of incredible numbers of yellow egg cases that can cover large rocks, flotsam and just about anything else too big to get carried away with the tide. The term “sea oats” is used to describe the “fields” of these yellow oblong egg cases, which contain two to six dozen eggs each.

Dogwinkles, sometimes known as whelks, are a carnivorous sea snail in the class Gastropoda, the largest class of mollusks, which also includes limpets and abalone. All gastropods have a single shell, move around on a “foot” and have a multiple-toothed scraping radula used for eating.

The dogwhelk, or frilled dogwinkle, Nucella lamellosa, is one of the most common whelks in Puget Sound. They can be found as far-flung as the Aleutian Islands to California, and individual appearances of this species can be so highly variable they fool collectors. From white to brown, orange and even purple, the frilled dogwinkle’s shell isn’t even necessarily frilled. Typically, Vashon’s beaches host smooth-shelled specimens, but people have found beautifully frilled orange and white shells.

We might even get to see some frilled dogwinkles feeding on their preferred diet of acorn barnacles and mussels. They spend one to two days drilling a hole in their prey’s shell with their file-tooth radula, and once they gain access to the soft flesh inside, they use their radula to scrape out their meal. In turn, the frilled dogwinkle’s rank in the marine food web is to serve as food for certain species of crab and star fish.

As part of a larger ecological picture, these carnivorous snails remind us of how interconnected our native creatures are with each other and their physical surroundings. We would do well to remember that as island citizens, we are their neighbors, and our actions are also interconnected with their livelihoods.

— Adria Pontious is a biologist, teacher and nature photographer, as well as a Vashon Beach Naturalist.

If you’d like to meet a frilled dogwinkle or other intertidal critters, including members of the Vashon Beach Naturalists, come to the nighttime beach walk at Tramp Harbor beach from 8 to 10 p.m. Saturday, Dec. 4, when there’s a low tide of –2.7 feet at 9:44 p.m. We will begin near the old dock pilings, where there’s parking between Ellisport and S.W. 204th St. Wear wading boots, bring a flashlight or headlamp and prepare for an evening of family-oriented fun.

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