You’ve been missing out if you haven’t spent time gazing down into tidepools, patiently scanning them for nudibranchs. Below are a few common nudibranchs I’ve been lucky enough to find and photograph in pools and exposed on rocks on Oregon’s shores. The photos are from the northern Oregon coast unless otherwise noted. My organization follows Lamb and Hanby (2005), and I refer to WoRMS for scientific names, but common names, if I use them, are my choice. The books, field guides, and online resources listed at the bottom of the page cover the nudibranchs shown below and many more.
And now, let’s touch base with a few nudibranch friends.
There are a few similar-looking yellow dorids, and distinguishing between them takes more practice than I have done. So, while recognizing some uncertainty, I think the examples below share more characteristics in common with Doris montereyensis than with any of the alternatives.
And for a different look, here’s a good-sized yellow dorid (est. 7-8 cm) on an early morning excursion across a sand-filled pool.
Beefy little leopards are always a treat, as are their lovely egg ribbon rosettes. You don’t want to be a sponge in their path.
Acanthodoris nanaimoensis, Nanaimo, or rufus-tipped dorid
Rostanga pulchra, red sponge dorid
Small and red, they’re easy to miss on the sponges where they spend a lot of time.
Dirona albolineata, white-lined dirona
Antiopella fusca, white-and-orange-tipped nudibranch
With one of the best scientific names, a common name is just a distraction. And, on a personal note, it’s the first nudibranch I discovered in a book and the wild.
The familiar shag-rug nudibranchs on the northern Oregon coast, Aeolidia papillosa, are part of a geographically wide-ranging complex described in 2016 (click here if you want to dig in). If I understand correctly, the Aeolidia we find in Oregon have been assigned to A. loui, a new species. Behrens et al. (2022) (see references below) give its range from Port Hardy, British Columbia, to Isla de Cedros, Baja California, Mexico. (A hallmark characteristic is warty tubercules on the rhinophores!).
Behrens, D. W., K. Fletcher, A. Hermosillo, and G. C. Jensen. 2022. Nudibranchs and Sea Slugs of the Eastern Pacific. MolaMarine.
Gotshall, D. W. 2005. Guide to Marine Invertebrates, Alaska to Baja California 2nd Edition (Revised). Shoreline Press.
Harbo, R. M. 2011. Whelks to Whales: Coastal Marine Life of the Pacific Northwest. 2nd ed. Harbour Publishing Co.
Kozloff, E. N. 1993. Seashore Life of the Northern Pacific Coast. 3rd ed. University of Washington Press.
Lamb, A. and B. P. Hanby. 2005. Marine Life of the Pacific Northwest. Harbour Publishing.
Sept. J. D. 2019. The New Beachcomber’s Guide to the Pacific Northwest. Harbour Publishing.
Biodiversity of the Central Coast’s Molluscs page. Accessed 01/17/2023;
Pacific Northwest Shell Club’s Nudibranch page. Accessed 01/17/2023.
Friends of Netarts Bay WEBS Mollusks page. Accessed 01/12/2023.
It’s worth scrolling down to the nudibranchs in Common Sea Life of Southeastern Alaska: A field guide by Aaron Baldwin & Paul Norwood. Accessed 01/12/2023.
Robbie Wheeling (2002 as edited). Hermissenda crassicornis (Eschscholtz, 1831). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/19/2023.
Cowles, D. (2005). Doris montereyensis (Cooper, 1862). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/17/2023.
Cowles, D. (2007). Acanthodoris nanaimoensis O’Donoghue, 1921. Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/18/2023.
Cowles, D. (2007). Rostanga pulchra MacFarland, 1905. Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/18/2023.
Cowles, D. (2007). Dirona albolineata Mac Farland in Cockerell & Eliot, 1905 (or Eliot, 1905). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/19/2023.
Cowles, D. (2008). Aeolidia loui (Linnaeus, 1761). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/19/2023.
Cowles, D. (2019). Diaulula odonoghuei Steinberg 1963. Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 01/17/2023.
I updated this page on January 19, 2023