The Caspian Tern is a seabird you can spot around Puget Sound from spring to fall. Of the world's 44 species of terns, this is the largest. Gray and white, with a black cap, big dark red bill, and four-foot wingspan, the Caspian Tern looks like a gull but has more sharply pointed wings and a habit of plunging into the water.
When Caspian Terns come back from wintering along the Mexican and Guatemalan coasts, look for them flying big circles over Puget Sound's bays. They stay high above the water, looking down as they fly. When the tern spots a fish, it suddenly plunges straight into the water, disappears for a moment, then leaps back into flight with the little fish clamped in its bill.
Why the name "Caspian?" This bird was first described for science around the Caspian Sea in Asia during the eighteenth century. It has one of the widest distributions of any bird in the world. Caspian Terns are along the coasts, and sometimes inland, on every continent except Antarctica.
In many places the Caspian Tern has become rare, but it's easy to find in Washington State. In fact, the world's largest nesting colony is at the Columbia River's mouth. Islands formed from dredging the river provide perfect Caspian Tern nesting habitat, and young salmon and steelhead descending the river are perfect tern food. Controversy over whose fish these are — birds or people — led to law suits and a complicated settlement. Still, it's always a welcome sign of spring when the Caspian Terns come back to Puget Sound and add to the varied life along the beach.
Of Puget Sound's 500 seaweed species, one especially grabs our attention. Walk the beach in fall or winter, and you're sure to find the long narrow tubes and flat blades of bull kelp washed ashore. This organism is one of the fastest growing of all that get energy directly from the sun. Usually living just one year, bull kelp may gain 8 inches a day eventually reaching from 20 to over 100 feet.
The kelp's holdfast, a root-like structure, anchors it to rock at the bottom of Puget Sound. A long tube connects the holdfast to a round float at the water's surface. This float ensures that the kelp's flat blades stay near the water's surface to gather the sun's energy.
You can see bull kelp growing in tangled bunches close to shore. Underwater, it forms a forest providing many different animals food or cover. These dense kelp forests also dampen waves and protect the shore from erosion.
People have long used kelp. Some parts served as containers, others can be made into fishing gear or medicines or ... pickles.
Next time you're at the shore, take a closer look at the amazing Bull Kelp.
The Blue Mussel is found almost everywhere there's saltwater and something to attach to. It's a two-shelled creature, or "bivalve," wedge-shaped, usually blue or purple and up to several inches long. In calm water it grows in dense clumps on docks, pilings, and rocks.
Like other bivalves, the mussel can move on its single foot. But usually the Blue Mussel stays put and holds itself in place in an amazing way. Near its foot, the mussel has a gland that secretes a liquid. When it finds a rock or other hard surface, the mussel uses its foot to draw some of the liquid down to that spot. The liquid quickly hardens under water, leaving a strong and slightly flexible thread. Then the mussel makes another attachment and another until it's held in place with a bunch of little guy lines.
If sediment is about to bury the mussel, it breaks these lines, glues a new thread further away, and pulls itself forward with the new line.
To feed, mussels draw in water between their shells and filter out tiny plants and animals. Blue Mussels process 3 quarts of water an hour doing this. When the tide drops, mussels survive out of water by shutting tight. Those attached lower in the water are easier prey for predators like the Purple Sea Star, which pries them open, and snails like the Dogwinkle, which drill into them and liquefy their insides.
Living in tense clumps, Mussels provide habitat for many smaller creatures that shelter beneath them. When you're checking out these abundant creatures at the beach, please avoid stepping on them or trying to detach them.
Look at that sturdy black body, that powerful red-orange beak, those stocky pink legs and red-ringed yellow eyes. It's the Black Oystercatcher! He's stalking the beach, breaking open limpets, chitons, mussels, and even oysters!
This bird is an important species along our shoreline, a sensitive indicator of the health of the rocky intertidal community. Over 80 percent of the Black Oystercatchers in the world live between southern Oregon and Southeast Alaska. There are only about 11,000 of them. In March, adult Oystercatchers return to their breeding territories. They nest near the intertidal zones of offshore islands. Each pair makes a small depression the size of a bowl close to the high tide zone.
To disguise the nest from predators, the birds line it with small pebbles and bits of shell. The female Oystercatcher then lays 2 or 3 eggs between early May and late June. If the nest is disturbed or the eggs destroyed the pair may try again and lay more. Chicks depend on their parents to bring them food, so nests are often near beds of mussels. For the 35 days before they're able to fly the Oystercatcher chicks are in danger from tidal surges, small animals, and human interference. A young Oystercatcher surviving these hazards may live 15 or 16 years. Enjoy and help preserve these colorful busy birds when you see them stabbing those sea urchins! Avoid areas where Oystercatchers are nesting.
Clean water is important for shellfish and other Oystercatcher food. You can help by properly disposing of motor oil and other potential pollutants and by avoiding chemical use around your home and yard.
Picture a straightened and very slender version of a seahorse floating upright in the water, and you'll have the Pipefish. The same bright green as eelgrass, this unusual fish has a pencil-slim body and can grow to 13 inches long. Pipefish live among the eelgrass where their color and upright posture give great camouflage as they imitate the swaying grass. Pipefish can even change color from green to brown to match the closest vegetation.
Their few fins are very small so Pipefish are slow swimmers. They stay vertical as they move, beating their fins rapidly and steering by moving their heads from side to side. Instead of scales this flexible fish has bonelike rings encircling its body.
The Pipefish's mouth has no teeth and is at the end of a tube-shaped snout. The fish eats by vacuuming in small shrimp and other tiny animals from some distance away.
Like its relative the seahorse, male Pipefish carry the young. The female courts the male. If successful in attracting him, she twists herself around him and deposits up to 900 eggs in the brood pouch on the underside of his body. A protective tissue forms over the pouch's opening and keeps the eggs safe inside. The male carries the developing young for several weeks before they emerge as swimming juveniles less than an inch long.
The greatest threat to Pipefish is the loss of eelgrass. Please help protect this valuable habitat which is so important for pipefish and many other marine animals. Follow the regulations established to protect eelgrass.
Hermit Crabs are very different from the little shore crabs we see at the beach. For one thing, each Hermit Crab lives in a borrowed shell because part of its body is soft and needs protection. Hermit Crabs are born in the ocean and drift until big enough for their first shell home. The growing Hermit Crab searches for an empty snail shell just the right size. To test the fit, the Hermit backs its soft abdomen inside the shell’s curves. If the fit's good, the crab's strong stomach muscles grip inside the shell, and two pairs of small claws hold on outside. For the rest of its life, the Hermit Crab carries its house on its back!
Besides its two gripping claws the Hermit Crab has a larger right claw for tearing food and defending itself and a smaller left one for eating. Together, these two claws can seal the entrance to the Hermit's portable home. It uses two other pairs of outer legs for walking and feeding.
What happens when this little guy grows too big for its borrowed home? It's time then for the crab to shed its outer covering and find a larger shell. It might wrestle one from another Hermit Crab whose house is just too tempting! Speaking of tempting, next time you see an attractive snail shell at the beach and go to collect it, please think again. You may be taking someone's home!
A fun way to learn more about Hermit Crabs and their intertidal world is reading Pagoo by Holling Clancy Holling (1957). It's a great children's book that adults enjoy too.
Could that thing moving in the tidepool really be a rock covered with seaweed? More likely it’s the little crab that camouflages itself by decorating its shell. Just an inch and a half long, the Decorator Crab uses its jointed legs to snag bits of sea weed, sponges, anemones and other things living around it. The crab places each living organism on its shell where specialized hairs work like Velcro to hook each item in place. Once attached, the collected plants and animals keep growing and hide the crab from predators. For extra protection, it can decorate even its sides and claws and blend perfectly into the tidepool scene.
Just as with other crabs, the body of the Decorator Crab grows, but its hard outer shell does not. So from time to time, the crab "molts," cracking its shell open at the back and slipping out. While a new shell forms and hardens the crab stays out of sight. Once that's done, it recycles the living things from its old shell by attaching them to the new one. Then off the Decorator Crab goes, blending in with its surroundings once more.
The population of Decorator Crabs isn't in danger; but oil spills and run-off of pesticides and other chemicals from the land endanger the crabs' habitat. As stewards of the oceans, we must carefully dispose of hazardous materials like these or, better yet, use environmentally safe products instead.
Imagine a shellfish able to jump away from danger. The Heart Cockle is a soft-bodied animal that lives between two hard shells connected by a hinge. Sensing a predatory sea star nearby, the cockle sticks a muscular foot from between its shells and gives a sudden push, vaulting up and out of harm's way.
Looked at edge-on, the cockle’s shells form a heart-shape, so it’s called the "heart" cockle. It’s one of many kinds of bivalves living in Puget Sound. Cockles feed by drawing water in one tube, or siphon, filtering out tiny edible creatures, and then expelling the water through another tube. Because these siphons are short, cockles lie just beneath the sandy surface or even on top, visible in shallow water.
Remember that to collect cockles and other bivalves like clams you need a Shellfish License from Washington Department of Fish and Wildlife. And to make sure they’re safe to eat you should always check the Shellfish Safety Toll-free Hotline before you dig for dinner.
Purple Varnish Clam
The Purple Varnish Clam is a Northwest newcomer. It's not clear yet how this fast-spreading bivalve may affect other marine creatures.
Biologists first noticed the Purple Varnish Clam near Vancouver Island in the late 1980's. It's native to Japan and Korea and probably came to North America in ballast water. Large ships use tanks of seawater to give them stability and then pump it out when taking on cargo. Small clams and other creatures can be taken in with the sea water and end up being released into the environment at the other end of the voyage.
Since its arrival in North America, the Purple Varnish Clam has spread south to Puget Sound and along the Pacific Coast. Its flattish brown shell grows to 2 1/4 inches across with a varnished shine outside and a purple interior. It lives in shallow water, especially near freshwaters seeps, and can quickly dig itself 8 inches deep into sand or gravel. At night the clam extends two long tubes to just above the sea floor; one takes in water from which the clam filters food and the other sends out waste. Unlike many other clams, this one can also feed as it moves along. A single, muscular foot propels it, and as bits of food stick to the foot, the clam transfers them to its mouth.
With a shellfish license you can harvest Purple Varnish Clams, but it's important to check first that they're safe to collect where you plan to go. These clams concentrate toxins at higher levels than other types and hold onto the toxins longer. Call the Shellfish Safety Hotline: 1-800-562-5632.
This unusual mollusk, also called the giant Pacific chiton, grows to 13 inches, making it the world's largest chiton. For over 500 million years it has remained unchanged. Chitons are oval-shaped and wear a shell consisting of eight separate overlapping plates. Hard, leathery, reddish brown flesh covers the plates of the Gumboot Chiton and gives it its name.
Chitons don't have eyes or tentacles like many marine creatures, but their shells are equipped with light-sensitive organs. During the day, this mollusk hides under rocks or in crevices, then comes out at night to feed. The chiton uses its broad, muscular foot called a radula to scrape up bits of the red algae it eats. The radula's little teeth are magnetic, enough so that a magnet could lift the creature! Digested red algae helps give this animal its reddish brown color, making it look like a wandering meatloaf. At low tide an exposed Gumboot Chiton can breathe atmospheric oxygen. Each spring, these creatures come ashore to spawn.
The Gumboot holds onto rocks with something like suction cups, but its grip is weak. Storms easily pull chitons off rocks and wash them onto the beach. When the plates of a dead chiton are found, beachcombers call them "beach butterflies" because of their shape. Maybe you’ve seen a few yourself.
To Native people living along the coast, the giant Pacific chiton was an important food and plays an important part in stories and legends. Protect our rocky shores for future generations by being respectful. Observe chitons and other creatures without pulling them off the rocks.