Eyes Under Puget Sound: critter of the month – the skeleton shrimp

A female skeleton shrimp sways spookily with the ocean current.

This Halloween, we’d like to introduce you to one of the most bizarre groups of crustaceans in Puget Sound – the skeleton shrimp. From their spindly skeletal bodies to their creepy waving movements, these otherworldly critters are bound to make your skin crawl!

Skeleton crew

If you can put aside their alien appearance, skeleton shrimp are fascinating creatures. Unlike most of their cousins in the order Amphipoda (which actually do resemble tiny shrimp), the skeleton shrimps (or “caprellids”) are specialized for clinging rather than swimming in marine habitats. If they want to move, they have to crawl along like inchworms. They also have adaptations for camouflage, changing colors to blend in with their surroundings. You can find them hiding among other invertebrate critters on docks and pilings, using their hook-like back legs to hang on to the plant-like fronds of colonial hydroids and bryozoans. They can also be found in beds of seaweed and eelgrass, their lanky bodies waving about in the water current.

Left: Caprella mendax.

Center: A female Tritella pilimana broods her eggs in a special pouch. Image courtesy of Dave Cowles, wallawalla.edu.

Right: Tritella pilimana.

Skeleton at the feast

Skeleton shrimp have varied feeding methods – some species are filter feeders that wait for food to come to them, while others are predators, hunting for worms and crustacean larvae. Some eat detritus (dead particulate material), and some species like to munch on tiny microalgae called diatoms. In fact, skeleton shrimp are so good at grazing on diatoms that their presence is thought to keep eelgrass beds healthier by removing diatoms that encrust the blades. Fish and larger invertebrates pass these nutrients up to the higher trophic levels when they eat the skeleton shrimp.

Poison punch

The male gnathopod of Caprella cf californica.

A skeleton shrimp’s unusually large claws, called gnathopods, play an important role in their mating behavior. In some species (including species of Caprella found in Puget Sound), the male’s gnathopods are armed with a poison-producing gland. The toxins they make aren’t harmful to humans, but when two males fight over a mate, the outcome can be deadly.

Naked truth

Mating can be tricky for these critters because their window of opportunity is short. Like all arthropods, they shed their exoskeletons to grow in a process called molting. The female is only able to mate right after molting, when her new exoskeleton is still soft. She carries her eggs in special flaps called brood pouches, and the young hatch out looking just like miniature adults, immediately inching away to find their own little branches to attach to.

Skeleton key

For taxonomists, the scariest thing about skeleton shrimp is identifying them! We encounter over half a dozen species in Puget Sound, and telling them apart can be quite the daunting task. We look for key features such as the length of the antennae, whether or not the animal has a spine on its head, and the shape of its gnathopods. Despite the taxonomic challenges, we do enjoy seeing these weird little beasts in our samples, although the swaying and claw-waving of the live ones can be a bit unnerving. So if you really want to get spooked on Halloween, head down to a dock, peer into the murky water, and hunt for tiny skeletons!

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program

Our benthic taxonomists, Dany and Angela, identify and count sediment-dwelling organisms as part of the Marine Sediment Monitoring Program. They track the numbers and types of species they see in order to understand the health of Puget Sound and detect changes over time.

Dany and Angela share their discoveries by bringing us a benthic Critter of the Month. These posts will give you a peek into the life of Puget Sound’s least known inhabitants. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr.

Marine spatial plan adopted to protect our coastal resources

Ruby Beach on Washington's Pacific coast.

Did you know that only four Washington counties – Clallam, Grays Harbor, Jefferson and Pacific – have marine shorelines on the Pacific Ocean?

Together, these four jurisdictions account for 331,000 acres of marine waters and have 157 miles of open ocean coastline. Our coastal communities and coastal Indian tribes have a rich history and maintain a unique relationship to our coastal resources.

Yet, there are increasing demands on these resources – including new projects and uses that can potentially create conflicts with uses or damage our marine resources.

State develops, adopts marine spatial plan

To ensure Washington maintains a resilient, healthy coastal marine ecosystem, we worked closely with our partners at the Washington departments of Fish and Wildlife and Natural Resources (DNR) to adopt a new tool – called a “marine spatial plan” – to help make coordinated, science based decisions about proposed new ocean projects and uses.

The guidance establishes processes for coordinating among local and tribal governments and state and federal agencies and for ensuring interest groups and the public have opportunities to weigh in on future projects.

Since the plan contains new policies to protect sensitive ecological areas and fisheries, the plan also puts the state in a strong position to review and shape new ocean activities in areas of state and federal waters in the plan's study area.

The state worked closely with local and tribal governments, other state agencies, the Washington Coastal Marine Advisory Council, environmental and planning groups, the private sector and the public to develop the plan.

Plan will help evaluate new ocean projects, uses

The new guidance will help us evaluate new proposals seeking to be located between Cape Flattery and Cape Disappointment. The plan covers a patch of the Pacific nearly 6,000 square nautical miles in size.

Right now, most of ocean uses in Washington center on recreation, maritime shipping, coastal fishing and shellfish aquaculture. But we know we have to be ready to effectively assess proposals for new uses and activities such as:

• Renewable energy
• Mining
• Dredged material disposal
• Marine product harvesting
• Offshore aquaculture operations

Our marine spatial plan builds on a 2010 law passed by the state legislature. Six years in the making, the new plan outlines the data and information that are needed to evaluate new proposals – especially the potential effects new ocean uses could have on people, our local communities and the environment.

It also integrates existing state policies and standards that projects must satisfy such as demonstrating that projects have no likely, long-term significant adverse impacts to resources or uses.

Competition for small fraction of ocean ecosystem

Michele Culver, Intergovernmental Ocean Policy Manager for state Fish and Wildlife said “while the ocean is a vast ecosystem, there is competition to use a small fraction of it.”

The plan, Culver said, provides a way for the state to carefully consider the placement of proposed new uses and the effects on other important activities, such as fishing, that occur in the same area.

  

While the plan establishes protections for fisheries and ecologically sensitive areas in state waters, it doesn’t change current management or permit processes for existing marine activities such as fisheries management plans or shellfish aquaculture.

Before we adopted the guidance, the state sought and received comments on the draft plan and a related environmental impact statement which helped us evaluate anticipated impacts that could arise from adopting the plan.

We carefully assessed all the comments we received and they helped us refine the plan. We will submit the marine spatial plan as part of Washington’s federally-approved Coastal Zone Management Program.

Get involved and stay current on marine spatial planning
  

The new state marine spatial plan creates an inclusive decision-making process that carefully considers economic, social, ecological, and cultural interests and gives all users an avenue for having input on the most appropriate strategies to guide and evaluate future uses of our Pacific Ocean waters.

Everyone can keep tabs and get involved in with marine spatial planning in Washington.

Eyes Under Puget Sound: Critter of the Month – Tube-Dwelling Anemone

Wildflower season is upon us here in the Pacific Northwest, and this month’s critter is a reminder that the marine environment has “flowers” of its own! Meet the tube-dwelling anemone, a delicate blossom at the bottom of Puget Sound.

The tube-dwelling anemone Pachycerianthus fimbriatus,
photographed at the Seattle Aquarium

Blooms of many colors 

With their wispy crown of tentacles, tube-dwelling anemones might easily be confused with tube worms, but they actually belong to the phylum Cnidaria, which also includes corals and jellyfish.

These tube-dwellers are not true anemones; they are in a special group called cerianthids, and Pachycerianthus fimbriatus is the only one found in Puget Sound. They range in color from white to purple to orange, and often grow in large groups that look a bit like flowers in a meadow.

P. fimbriatus can be found from southern Alaska to Baja California, in depths of up to 268 meters (about 800 feet). In our sampling, we encounter them most frequently in Bellingham Bay, Sinclair Inlet, and the South Sound – places where they can easily burrow into the soft mucky sediment.

Different-colored individuals of
Pachycerianthus fimbriatus at the Monterey Bay Aquarium;
photo courtesy of Dave Cowles at inverts.wallawalla.edu

Down the tubes

P. fimbriatus has a soft, vulnerable body, so it burrows into the mud and creates its own protective dwelling around it. Its building materials are not sand or mud as you might expect, but a special type of thread secreted by the animal, called a ptychocyst (pronounced “TIE-co-sist”).

All cnidarians have nematocysts (stinging cells) but ptychocysts are unique to tube-dwelling anemones. The ptychocyst threads are woven together to form a thick, slippery casing that projects above the sediment’s surface, and may extend up to 1 meter (3 feet) in the mud below.

P. fimbriatus with its sea slug predator,
Dendronotus iris, climbing its tube.
Note the slug’s coiled white egg mass in the background.
Photo courtesy of John Yasaki, Oakland, CA.

The anemone can retract its entire body into the tube, which comes in handy when it encounters its main predator - the giant nudibranch, Dendronotus iris. The nudibranch grazes on the anemone’s tentacles, and also cleverly lays its eggs on the outside of the anemone’s tube, so its young are born right on top of their meal. All this snacking doesn’t necessarily mean death for the anemone – it has tentacles to spare, and can live up to 10 years.

Lord of the rings

P. fimbriatus can be easily identified by its two distinct rings of tentacles. The outer ring is long (used for reaching out to catch the small crustaceans it likes to eat) and the inner ring is short, used for transferring food to the mouth.

P. fimbriatus, close-up view of tentacle rings from above.
Photo courtesy of Mike Munroe, http://www.mikejmunroe.com/

In some species of tube anemones, the tentacles are also able to absorb ultraviolet rays and glow with a fluorescent light.

A preserved P. fimbriatus specimen with its
tube cut open to reveal the animal inside.

Race against slime

Although a living tube-dwelling anemone is a pretty sight underwater - with its colorful tentacles waving in the current - nothing makes us marine scientists groan more than seeing one in a freshly collected sediment sample.

When we catch P. fimbriatus in our benthic grab, the fine threads of its tube become a tangled mass, turning into a black slimy goo ball that entangles everything it touches. We try to separate these animals from the rest of the sample as soon as possible to avoid creating a giant mess!

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program

Critter of the Month

Our benthic taxonomists, Dany and Angela, are scientists who identify and count the benthic (sediment-dwelling) organisms in our samples as part of our Marine Sediment Monitoring Program. We are tracking the numbers and types of species we see in order to understand the health of Puget Sound and to detect any changes over time.

Dany and Angela share their discoveries by bringing us a Benthic Critter of the Month. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants. We’ll share details on identification, habitat, life history, and the role each critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr.

Eyes Under Puget Sound: Critter of the Month – The Heart Urchin

Happy Valentine's Day from this
adult specimen of Brisaster latifrons
collected from Puget Sound.

Be still, my heart (urchin)! During the time of year when candies and valentines are everywhere you look, it is only fitting that we present to you the most romantic creature in Puget Sound as February’s critter: the Heart Urchin.

The shape of my heart

Heart urchins are a type of sea urchin, which are in the phylum Echinodermata (meaning “spiny skin”), along with sea stars and sea cucumbers. Unlike most sea urchins, which are round, heart urchins appear heart-shaped because their bodies are elongate, with a small depression for the mouth at one end.

A living heart urchin is brownish in color, with its many spines giving it a furry appearance. Once the animal dies, however, the spines fall off, leaving the smooth white external shell, or test, exposed. The heart urchin test is made up of hundreds of hard interlocking plates, but it is actually quite brittle in dead specimens, which is why you will hardly ever find one washed up on the beach.

Different views of Brisaster latifrons missing a majority of its spines and revealing its white test.
Photo courtesy of Linda Schroeder (PNW Shell Club).

 

How deep is your love?

Brisaster latifrons, freshly collected by our team
from Puget Sound sediments.

Only one species of heart urchin, Brisaster latifrons, occurs in Puget Sound, and it is also the most common sea urchin we encounter during our sediment monitoring. B. latifrons can be found from Alaska to southern California, inhabiting soft muddy bottoms in deeper water depths of 51-1,166 meters (although Puget Sound depths only reach about 300 meters).

Growing up to 73 mm, the heart urchin is a fun and welcome sight in our sediment grabs. We just have to handle their fragile outer shells carefully – we don’t want to break any hearts!

This juvenile Brisaster latifrons displays the five
petals of the ambulacra on its dorsal (top) surface.

Flower power

Heart urchins have little in common with flowers, but they do have some surprisingly flower-like features. For example, underneath their spines are five flower petal-shaped outlines called the ambulacra.

The pedicillariae are another type of flower-like appendage that stick out of the test. They have serrated claw-like pincers that open and close at the end of their long stalks. They use these pincers for a variety of functions like defense, capturing food, parasite removal and more! When the pincers are open, they resemble flower blossoms, and when closed, they look like tulips. Now that’s a bouquet I’d like to give to my ex-boyfriend.

Close-up of the pedicillariae showing the
claw-like pincers closed (left) and open (right).

 

Eat your heart out

Top: Tube feet come out of the pores
that make up the ambulacra petal outline.
Bottom: Close-up of the tube feet.

Like other sea urchins, heart urchins have tube feet - slender tubes with suction cups on the ends that extend from pores in the ambulacra petals. These amazing feet serve multiple functions:

• Feeding: As the urchin burrows slowly through the mud, it ingests sediment and delicious organic matter along the way (this is called “deposit feeding”). The tube feet help by delivering food particles to the mouth.
• Locomotion: Thousands of tube feet work together at the same time to move the heart urchin wherever it needs to go. As the urchin moves along, the tube feet act like feelers or antennae to sense its surroundings.
• Respiration: Heart urchins primarily live in the mud. Modified tube feet that stick out above the mud’s surface act as a kind of snorkel to allow the urchins to obtain oxygen.

We hope after reading this blog, you too have fallen in love with the heart urchins.

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program

Brisaster latifrons classification guide

Critter of the Month

Our benthic taxonomists, Dany and Angela, are scientists who identify and count the benthic (sediment-dwelling) organisms in our samples as part of our Marine Sediment Monitoring Program. We are tracking the numbers and types of species we see in order to understand the health of Puget Sound and to detect any changes over time.

Dany and Angela share their discoveries by bringing us a Benthic Critter of the Month. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants. We’ll share details on identification, habitat, life history, and the role each critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr.

Eyes Under Puget Sound: Critter of the Month - Black-Eyed Hermit Crab

A Black-Eyed Hermit peers out from its
moon snail home near Victoria, British Columbia.
Photo courtesy of Keoki Stender.

Happy New Year! Following the southern tradition of eating black-eyed peas for luck on New Year’s Day, we bring you the adorable Black-Eyed Hermit Crab as January’s Critter of the Month.

Home is where the shell is

Like most hermit crabs, the Black-Eyed Hermit is never far from home. The crab’s body is soft and fragile, so it seeks protection from predators inside an empty snail shell. If the crab feels threatened, it can retract its entire body into the shell, leaving only its not-so-tasty claws exposed.

Hermit crabs carry their shell homes around with them wherever they go, which might seem tricky given the size and weight of these portable dwellings. However, the coiled hermit crab body shape is perfectly designed to fit into a “mobile home.” In addition, the crab has structures near its tail called uropods (shown in the photos below). The hook-like uropods grasp the inside of the shell, holding it in place as the crab crawls along.

Left: Side view of a preserved Black-Eyed Hermit specimen; the arrows indicates the hook-like uropods.
Right: Close-up of a uropod.

 

Moving on up

The Black-Eyed Hermit is one of the largest hermit crabs in Puget Sound (with a body-shell length of about 4.5 cm) so it prefers to reside in a nice roomy moon snail shell. As the hermit crab grows, its borrowed shell stays the same size, so it will eventually outgrow its home and upgrade to something with a larger floor plan. When free shells are scarce, the crab may try to “evict” one of its neighbors, forcing the other crab to pack its bags and move out.

A close-up dorsal (top) view of the head, showing
the black eyes. Photo courtesy of Dave Cowles.

Easy on the eyes

Although there are multiple species of hermit crabs in Puget Sound that have red stripes on their bodies and look relatively similar at first glance, our Hermit can be easily identified by its large, oval-shaped black eyes (the other species have yellow or green eyes). The Black-Eyed Hermit is also the most common hermit crab species we encounter during our sediment monitoring. It can be found from Alaska to southern California, inhabiting sandy or muddy bottoms from the tide line to about 150 meters (almost 500 feet!) deep.

Love is a battlefield

Another feature that sets the Black-Eyed Hermit apart is its distinct claws or “chelipeds”, which have large spines on the dorsal (top) surface and smooth undersides. Like other hermits in the family Paguridae, its chelipeds are unequal in size – the right is slightly heftier than the left.

Left: The spiny cheliped (claw) of the Black-Eyed Hermit. Right: Close-up of the spines on the cheliped’s dorsal surface. Photos courtesy of Dave Cowles.

These large claws come in handy when the male Black-Eyed Hermit is looking for love. First, he finds a female crab and grabs her by the shell. He then carries her around with him for up to several days until she is ready to mate, fending off other males with his claws.

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program taxonomists

Critter of the Month

Our benthic taxonomists, Dany and Angela, are scientists who identify and count the benthic (sediment-dwelling) organisms in our samples as part of our Marine Sediment Monitoring Program. We are tracking the numbers and types of species we see in order to understand the health of Puget Sound and to detect any changes over time.

Dany and Angela share their discoveries by bringing us a benthic Critter of the Month. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants. We’ll share details on identification, habitat, life history, and the role each critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr.

Eyes Under Puget Sound: Critter of the Month – Sweet Potato Sea Cucumber

With its smooth, plump body, this month’s critter bears a resemblance to items you might find in a grocery store. Meet Molpadia intermedia, the Sweet Potato Sea Cucumber.

Our Critter of the Month Molpadia intermedia, freshly collected from mud under Puget Sound.

Although the Sweet Potato Sea Cucumber may look and sound like a vegetable, you definitely don’t want to go slicing up this slimy mud-dweller on your salad!

Brother from another mother

Sea cucumbers like Molpadia intermedia are part of a larger group called Echinodermata that also includes sea stars, brittle stars and sea urchins.

Superficially, sea cukes don’t look much like their echinoderm kin, but they all have 3 characteristics in common:

1. A water vascular system made up of tubes and valves which allows movement, digestion, and breathing by pumping water throughout the body
2. Pentaradial symmetry – the body is organized in 5 symmetrical sections
3. An internal skeleton containing calcium carbonate

Get under your skin

In the case of sea cucumbers, the internal skeleton takes the form of tiny particles called ossicles, embedded in the outer skin. Taxonomists can identify sea cucumbers by examining the shape of their skin ossicles under a light microscope.

M. intermedia has 2 kinds of ossicles:

1. “Tables” – flat plates with tall, narrow spires
2. Plates shaped like tennis racquets, filled with tiny holes

LEFT: Microscopic images of M. intermedia’s skin ossicles. The table images show a dorsal view (top)
and lateral view (bottom). The racquet-shaped ossicle shows the small perforations throughout.
RIGHT: Close-up of M. intermedia’s skin with ossicles (tables and clusters of racquets) visible.

In  addition to ossicles, M. intermedia has something else lurking inside its skin: tiny iron- and phosphate-rich blobs called phosphatic bodies. You can see these microscopic orange blobs in the image to the right above. The animals get more of these as they get older. Scientists think these granules serve to strengthen the connective tissue in the skin.

No foot to stand on

A living Molpadia specimen with its feeding
tentacles extended. This individual is waiting
to be weighed and measured in the field.

Sea cucumbers typically have rows of tube feet running the length of their bodies; however, M. intermedia lacks tube feet, giving it a smooth and shiny appearance. Its soft, cylindrical body has muscles running its length. These muscles can expand to lengthen it (up to 43 cm) or contract to shorten it into a little ball when it is disturbed.

At one end of its body is a mouth surrounded by 15 feeding tentacles. These short finger-like (digitate) tentacles help push food into its mouth as it ingests sediment while burrowing. At the rear end of its body is a short, stubby tail.

Couch Potato

M. intermedia seldom moves, making it an easy target for its main predators, including the Sand Star, Luidia foliolata, and fish. In some areas, M. intermedia lives in densities of up to 15 per square meter, and individuals tend to aggregate in groups of two to six. Talk about a sea cucumber buffet!

M. intermedia in a sediment sample which
has been partially rinsed through a sieve.

Critter of the Month

Our benthic taxonomists, Dany and Angela, share their discoveries by bringing us a benthic Critter of the Month. Dany and Angela are scientists who work for the Marine Sediment Monitoring Program. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants.

In each issue we will highlight one of the Sound’s many fascinating invertebrates. We’ll share details on identification, habitat, life history, and the role this critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr. Look for the Critter of the Month on our blog.

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program

Is Puget Sound healthy? Join us May 10 to find out!

By: Jessie Payne, Environmental Assessment communications manager

A big question has been on everyone's mind lately: 

Is Puget Sound healthy? 

This may seem like a simple question, but talk to our scientists, and you'll hear that the answer can be quite complicated. The answer depends on the situation and what aspect of health you're interested in. 

Today in Ecology's podcast, we sit down with our Scientific Environmental Modeling Engineer Mindy Roberts to discuss this question and learn about a talk she'll give tomorrow evening in Tacoma for the Pacific Science Center Science Café. 

Join Mindy at the Science Café event

Describing the health of Puget Sound is as complicated as describing your own personal health. At the Science Cafe, Mindy will dive into some of the latest water quality findings and discuss ways that everyone can help improve the health of Puget Sound.

Join Mindy in Tacoma to learn about some of the latest science we have on Puget Sound. Bring friends who want to understand the different ways we measure its health.

What?	Pacific Science Center Tacoma Science Café “Is Puget Sound Healthy?”
When?	Tuesday, May 10 at 6:30 p.m.
Where?	The Swiss Restaurant & Pub 1904 Jefferson Avenue, Tacoma

Science Cafés are open to all ages. No science background is required, and no question is too basic. Learn more about the Pacific Science Center Science Café event.

Puget Sound science at Ecology

Scientists at Ecology collect, research, and provide credible data to guide our agency's environmental choices for Washington. They work to help us track our environmental health, and to ensure the actions we've taken are working. Learn about our Puget Sound science.

Critter of the Month: The cactus worm

By: Dany Burgess & Angela Eagleston, Environmental Assessment Program

Meet the Eyes Under Puget Sound Critter of the Month, Priapulus caudatus, otherwise known as the cactus worm. January's critter is quite a beauty...

Priapulus caudatus – Cactus Worm

Cactus of the sea

Priapulus caudatus. Photo courtesy of Atli Arnarson

This month’s critter may look like a cross between a worm and a cactus, but it is actually neither. Priapulus caudatus belongs to a group of animals called cephalorhynchs, which means “beak-head.” This group is a mixed bag of several different types of animals that share a special feature – a swollen tubular mouthpart called a proboscis. The proboscis has tiny beak-like teeth and can be turned inside out to hook prey and then retracted back inside the body. Enlarged to human size, it could be the terrifying star of a science fiction movie.

Lifestyles of the weird and muddy

P. caudatus is actually giant in comparison to its microscopic relatives, reaching up to 15 centimeters in length! It prefers the cold water of high latitudes, and can be found from the shoreline all the way to the deep sea (about 7,500 meters.) Its favorite habitat is the soft silty mud of the sea floor, where it burrows hind-end-first by expanding and contracting the muscles in its body wall. It spends most of its time moving slowly through the sediment, reaching out with its proboscis to ensnare marine worms and any other slow-moving creatures it encounters.

Click to enlarge

We are family!

The family Priapulidae is a special group of cephalorhynchs that actually has more in common with shrimp or crabs than with worms. As they grow, priapulid adults and larvae shed their skin in a molting process called "ecdysis." The ecdysis process is similar to how crustaceans shed their outer shells.

Today there are only about 16 species of priapulids world-wide, but numerous priapulid fossils have been found dating back millions of years to the Cambrian period.

Priapulus caudatus, preserved specimen

The priapulid doesn’t fall far from the tree

Modern-day priapulids aren’t that different from their ancient ancestors. Their soft, unsegmented bodies are divided into three sections (see photo to the right):

1. Introvert
   The animal’s anterior (head) end which contains the mouth.
2. Trunk
   The midsection, which has a ringed appearance and is covered with tiny bumps called papillae.
3. Caudal appendage
   A long feathery “tail”, which serves various functions depending on the species. Scientists speculate that the tail of P. caudatus may serve as a breathing organ.

Critter of the Month

Close-up of caudal appendage

Our benthic taxonomists, Dany and Angela, share their discoveries by bringing us a Benthic Critter of the Month. Dany and Angela are scientists who work for the Marine Sediment Monitoring Program. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants.

In each issue we will highlight one of the Sound’s many fascinating invertebrates. We’ll share details on identification, habitat, life history, and the role this critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr. Look for the Critter of the Month on our blog.

Critter of the Month: The British Columbian Doto

By: Dany Burgess, Angela Eagleston & Diana Olegre, Environmental Assessment Program

Doto columbiana, the British Columbian Doto

Another Northwest slug?

The Northwest is known for the slugs and snails that thrive in the undergrowth of its damp mossy forests. Critters like this also live under the sea, like our Eyes Under Puget Sound Critter of the Month, Doto columbiana, commonly called the British Columbian Doto.

It’s a nudibranch

The British Columbian Doto belongs to a category of animals called nudibranchs (pronounced NEW-dih-bronks), often referred to as sea slugs. There are over 3,000 species of nudibranchs worldwide, but fewer than 20 species exist in the Puget Sound.

D. columbiana - profile of whole
preserved specimen stained pink

D. columbiana is a tiny critter, only reaching about 8 mm in length. Along the sides of its body are soft lumpy structures called cerata (plural for ceras) that look like clusters of grapes and function as digestive glands. The leopard-like coloration on D. columbiana can vary between individuals but generally consists of brown mottling throughout the body along with darker rings at the base of each grape-like tubercle. You can see the tubercle, ceras and other body parts labeled in the photo of the preserved D. columbiana to the right.

Excuse me? My “antennae” are called rhinophores!

The antenna-like structures on the nudibranchs’ heads are called rhinophores. These are a type of chemo-sensory structure, allowing nudibranchs to sense the world around them. The word “rhinophore” comes from the Greek word “rhino,” meaning nose, which is appropriate since they function as an organ of “smell.”

However, while humans smell scents in the air with their noses, nudibranchs “smell” or detect scents that are dissolved in the sea water around them to find food. The rhinophores’ worm-like appearance makes them an easy target for predators, so they can be quickly retracted into a trumpet-shaped rhinophore sheath for protection.

You are what you eat

D. columbiana on a colony of the hydroid Aglaophenia

Nudibranchs are carnivorous and get their pigmentation, or colors, from the food they eat. Nudibranchs that eat brightly colored creatures are brighter too. In fact, many have brilliant bodies of intensely contrasting colors.

The British Columbian Doto is quite drab by comparison. D. columbiana eats hydroids from the genus Aglaophenia. Hydroids are colonies of tinier critters called “polyps” that are related to jellyfish. An Aglaophenia colony looks like a brown fern frond or feather plume, and these neutral colors are incorporated into D. columbiana’s body to help camouflage it from predators.

D. columbiana conveniently lives on what it eats as well, laying its eggs on the underside of the hydroid’s branches. When the eggs hatch, the young larvae have shells which disappear as the nudibranchs become adults.

Taxonomy troubles

D. columbiana, like many soft-bodied critters, does not preserve well. The colors can be lost and the shape can become distorted. Benthic taxonomists, the scientists who identify these small marine critters, have to look closely at features like the cerata and rhinophores to determine which critter they have collected.

Eyes Under Puget Sound Critter of the Month

Our benthic taxonomists, Dany and Angela, share their discoveries by bringing us a Benthic Critter of the Month. Dany and Angela are scientists who work for the Marine Sediment Monitoring program. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants.

In each issue we will highlight one of the Sound’s many fascinating invertebrates. We’ll share details on identification, habitat, life history and the role this critter plays in their sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr. Look for the Critter of the Month every month on our blog.

Eyes Over Puget Sound: Fall arrives with hordes of jellyfish

Fall is here but our September Eyes Over Puget Sound flight showed us that Puget Sound is still at record high water temperatures. Some rain has returned to our region, but air temperatures are warm and river flows remain unusually low.

Click here to see the September report.

Warm waters and sunny conditions fostered green tides throughout the Sound, raising a stink along some local beaches. Learn more in our Personal Field Impressions section. 

Waves create stripes of sediment in Bellingham Bay.

The good news? Puget Sound is saltier than normal, which allows oxygen-rich surface waters to more easily mix to greater depths. This means more oxygen for fish and other marine wildlife after a long and stressful summer. We did measure low oxygen in a couple places on our flight this month, such as the coastal bays, Hood Canal and the southern end of Puget Sound. 

This year's strange and prolific jellyfish blooms have continued. Large jellyfish groups were seen in the south end of the Sound, the Kitsap Peninsula and the waters near Orcas Island. 

We also observed unique patterns formed by sediment plumes in Bellingham Bay. 

What's Eyes Over Puget Sound?

Eyes Over Puget Sound combines high-resolution photo observations with satellite images, ferry data from travel between Seattle and Victoria BC, and measurements from our moored instruments. We use a seaplane to travel between our monitoring stations because they are so far apart.

Once a month, we take photos of Puget Sound water conditions and turn those out, along with data from our stations, in the monthly Eyes Over Puget Sound report.

Learn more and see other issues on our website.

Eyes Over Puget Sound: Sunshine fuels Noctiluca blooms and green islands

By Jessica Payne, Environmental Assessment Program communications manager

In this month's Eyes Over Puget Sound report, the data shows our current trend of unusually warm water temperatures is continuing in central and south Puget Sound. 

Willapa Bay, however, returned to expected water temperatures as a result of cooler water pushing in from deep in the ocean. That is good news for the marine wildlife that live in Willapa Bay, but Puget Sound is still feeling the heat!

Click here to see the July report.

What in the world is this!?

Although it might look like some magic concoction created in the laboratory of a science fiction novel, it's actually nature and sunshine mixing up tiny plants and animals in the sound.

View of the organic floating islands
from the air. Click photo to enlarge.

What's the mixture?

Our scientists saw many pockets of this mixture during this week's marine monitoring flight. They call them "extensive mats of organic debris mixing with a fading Noctiluca bloom".

In other words, the green you see above is floating islands of algae. This floating plant matter grows, flows and begins to spread out across the water.

What's this Noctiluca I keep hearing about?

The orange is the last remnants of the Noctiluca bloom we saw so much of in last month's issue. The tomato soup-colored Noctiluca blooms are non-toxic plankton and occur naturally every year. See microscopic photos of Noctiluca and many other Puget Sound plankton in a guest piece from King County's Environmental Lab.

We saw the most of these organic debris islands in central Puget Sound, between Seattle and Bainbridge Island, although they extended north up to Camano Island and Padilla Bay. We also saw many red-brown and brown blooms of other types of algae going strong in southern inlets and around the San Juan Islands.

WCC gives a young scientist the experience of a lifetime

For Brooke, our Washington Conservation Corps (WCC) intern, working with our marine monitoring team has been dynamic and fun. Whether she's running equipment, analyzing samples in the lab or catching jellyfish, she's right in the action.

Read about Brooke's experience in the Personal Field Impressions section of this month's report. She tells of her adventures working with Puget Sound critters and gives advice for other young scientists who are interested in environmental work.

Want to work with Ecology? WCC will be opening it's recruitment period statewide on July 15. These are AmeriCorps positions that provide paid opportunities for young people and veterans to gain experience in natural resource work. Brooke's internship is one of their Individual Placement positions. Learn more about joining a crew or applying for an Individual Placement like Brooke's on the WCC webpage.

What's Eyes Over Puget Sound?

Eyes Over Puget Sound combines high-resolution photo observations with satellite images, ferry data from travel between Seattle and Victoria BC, and measurements from our moored instruments. We use a seaplane to travel between our monitoring stations because they are so far apart.

Once a month, we take photos of Puget Sound water conditions and turn those out, along with data from our stations, in the monthly Eyes Over Puget Sound report.

Learn more and see other issues on our website.