Protecting and Restoring the Morro Bay Estuary.
Robin Agarwal

Sea Slugs on the Move: Bent on World Domination, or Opportunistic Travel Bums?

Polycera atra (top) and Polycera hedgpethi on Bugula brozoan prey San Luis Obispo County, California

    Sea Slugs on the Move: Bent on World Domination, or Opportunistic Travel Bums? With the passing of the very low, very early morning tides of summer, tidepooling minds must reluctantly turn away from the outer edges of our coastline for a few months, until the autumn minus tides return in mid-October. And what better topic to occupy our Covid/smoke/asteroid/politics stressed minds than possible world domination by sea slugs? I exaggerate, of course. We won’t be marching in lines and waving tiny nudibranch flags any time soon. But there has been a quiet movement of sea slug populations taking …

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The Perfect Social Distancing Activity: Early Morning Tidepooling for Nudibranchs in San Luis Obispo County

A Limacia cockerelli nudibranch from the front. It is white with orange-tipped cerata.

    Now through October is the peak of the nudibranch-viewing season. Wait, what? You didn’t know there was a season for looking at nudibranchs? Well, there is, at least for some of the flashiest species found in the tidepools of the Central Coast. Scuba divers have a bit more time and options, but for those of us who look for nudibranchs with our heads above water, the early morning hours of late summer offer us some of the best opportunities to see these colorful marine gastropods in the intertidal. In previous blogs for the Estuary Program, I’ve gone into …

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Rare Nudibranch! Two Citizen Scientists find Cerberilla pungoarena in the Morro Bay Estuary

Cerberilla pungoarena in Morro Bay. Copyright passiflora4, Laura Schachterle and Thomas Hintz.

    Cerberilla pungoarena (Collier & Farmer, 1964) is one of those rare nudibranchs you may never see: only a few subtidal specimens have been reported since the mid-2000s. But now, fifteen years later and further north than they have ever been seen before, a single specimen of C. pungoarena was spotted and photographed a few months ago in shallow water in the Morro Bay Estuary by two intrepid nudibranch enthusiasts, Laura Schachterle and Thomas Hintz.  Nudibranchs are shell-less marine molluscs commonly called sea slugs. There are over 130 species of nudibranchs found in California, many brightly-colored. “Great find and …

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Your Top Blog Posts of 2019

  During 2019, you tuned in to the Estuary Program blog to follow field work projects, to learn about local wildlife, to track the health of the bay, and to see how you can help the estuary and watershed. Today, we’re sharing the posts readers visited most often this year across these four categories. If you haven’t read them yet, now’s a great time to catch up! Top Field Work Post Field Updates February 2019: Wet weather, Eelgrass Restoration, and Creek Monitoring This post shares rainfall totals, details the process of sediment sampling and analysis that we use, and explains …

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Sea Clowning Around: Triopha maculata and Triopha catalinae, by Robin Agarwal

Triopha Maculata Sun Salutation, photographed in Santa Cruz, CA by Robin Agarwal

  Spotted Triopha or Triopha maculata One of the most charming creatures found along the Central California coast is the Spotted Triopha nudibranch (Triopha maculata). With its colorful body, white polka dots, and bushy “beard”—properly called papillae—on the edge of its oral veil, this engaging sea slug is one of the most common you’ll encounter year-round, either on a dive or during a casual inspection of tidepools at low tide.  Triopha maculata color variants The only minor difficulty is realizing that you’re looking at one. Spotted Triophas come in at least two color variants that caused even veteran scientists to …

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A Sea Slug by Any Other Name, Guest Post by Robin Agarwal

Acanthodoris lutea nudibranch smells like citrus or cedar

This is the fifth post in our Sea Slug of the Month series by guest author, Robin Agarwal. A Sea Slug by Any Other Name: One Grossly Derivative Title Covering Three Random Thoughts About Scented Sea Slugs, Hopkins’s Rose, and the Ongoing Bother About Names “that which we call a rose By any other name would smell as sweet” —Juliet in Romeo & Juliet, William Shakespeare Although she was not particularly noted for her tidepool explorations, Juliet may have been surprised to discover that three of the nudibranchs (shell-less marine molluscs) living along the Central California Coast actually emit scents …

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The “Smalls”: The Teeniest, Tiniest Sea Slugs In California

Guest post by Robin Agarwal   This is the fourth post in our Sea Slug of the Month series. Find tips for spotting nudibranchs from the comfort of your local dock at the end of this post! So you’ve been tidepooling along your local reefs and you’ve found a few nudibranchs: Opalescents, Sea Lemons, Spanish Shawls, Hopkins’s Rose, Triophas. Maybe you’ve practically tripped over ginormous squishy Sea Hares. Boring, right? What a snooze, all those flamboyant colors, shapes, and bizarre anatomy. After all, those nudibranchs are over an inch long, and therefore way too easy to find.  If this is …

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Sea Slug of the Month – Yellow Blobs of Awesomeness, Guest Post by Robin Agarwal

    Yellow Blobs of Awesomeness: Sea Goddesses, Sea Lemons and That One with the Tentacles Guest post by Robin Agarwal   Humans like sea slugs. They’re harmless to humans, but voracious predators if you’re a hydroid or a sponge. They come in a variety of cool shapes and sizes, and have fascinating life histories that allow one to throw around words like ‘nudi’ and ‘hermaphrodite’ with impunity in mixed company. But best of all, nudibranchs appeal mightily to humans’ attraction to pattern and color. We cannot resist taking a closer look at something bright and colorful as we explore …

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Sea Slug of the Month – Morro Bay’s ‘Gateway Nudi:’ Opalescent Nudibranch, Guest Post by Robin Agarwal

Three Opalescent Nudibranchs (Hermissenda opalescens). Photograph courtesy of Robin Agarwal via Flickr Creative Commons License

    “Whoaaaa…what is THAT?” “It’s gorgeous, whatever it is.” “It’s moving!” “Dude, check this out!” “So BLUE!” “What IS it?” Music to a science educator’s ears, of course, thanks to the astonishing colors and reasonably viewable size of one of California’s most iconic sea slug species, the Opalescent Nudibranch (Hermissenda opalescens). Found throughout the Central California coast, these brightly-colored carnivores are often the first nudibranchs to astonish and delight the humans venturing into their intertidal world during seasonal low tides. Photograph of Opalescent nudibranch, (Hermissenda opalescens) taken in Monterey, California. Courtesy of Robin Agarwal, under Creative Commons license via …

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