Bryozoans

Below are examples of bryozoans I’ve found and photographed in the rocky intertidal or washed up on the beaches. I only have a few examples to share, just a few that have caught my eye. I use the organization followed by Lamb and Hanby (2005); common names are my choice, and all photos are from exposed northern Oregon shores unless noted. Experts cover these bryozoans and many more in the books, field guides, and identification resources listed at the bottom of the page.

Let’s celebrate the bryozoans!


MembraniporaĀ loves bull kelp blades, but it’s not opposed to the stipe. (I think this isĀ Membranipora, but there’s room for alternative interpretations.)

Round colonies on a drift bull kelp stipe resting on sand among other drifted material.
Bryozoan crust on a drift bull kelp stipe
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Red blades are frequent hosts of encrusting bryozoans. (Common as it is, assuming it’s the same in both panels, this one’s a mystery to me.)

Encrusted red blades laid out on Phyllospadix.
The bases of Cryptopleura/Hymenena blades can be heavily encrusted
An encrustation on a mysterious red bade.
I’m unsure of the host here, but the bryozoan looks similar to that shown in the left-hand panel
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In real life, and in this image, there’s a soft look, but far from it, the crust is hard. This example is from a low semi-protected vertical surface on a large exposed outcrop.

Resting among giant green anemones, this crust is about 6 cm (2.4 in) across
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Flustrellidra corniculata
Based on the images below, you might sayĀ FlustrellidraĀ tends to affiliate withĀ Laminaria sinclairii. I don’t know if there’s much association, but they commonly co-occur on surf-swept shores.

Flustrellidra corniculata and Laminaria sinclairii
In a world of distinctive creatures, F. corniculata holds its own
One of its common names is branch-spined bryozoan
Peeking out among red blades

It’s not uncommon to find drifted fragments on the beach, but detached pieces will have lost their vibrancy unless they are very fresh.

A drifted bryozoan fragment resting on the sand.
A drifted bryozoan fragment resting on the sand.
A drifted bryozoan fragment resting on the sand.
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References

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.

Light, S. F., 2007. The Light & Smith Manual: Intertidal Invertebrates from Central California to Oregon. 4th ed., edited by J. T. Carlton. University of California Press.

Sept. J. D. 2019. The New Beachcomberā€™s Guide to the Pacific Northwest. Harbour Publishing.


On-Line Resources

Biodiversity of the Central Coastā€™s Bryozoans page. Accessed September 5, 2023.

The Friends of Netarts Bay’s page on bryozoans. Accessed September 5, 2023.

Itā€™s worth scrolling down to Bryozoans inĀ Common Sea Life of Southeastern Alaska: A field guide by Aaron Baldwin & Paul Norwood. Accessed September 5, 2023.

Marney Pratt’s Bryozoans of the Pacific Northwest.

Cowles, D. (2005). Flustrellidra corniculataĀ Smitt, 1871.Ā Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed September 5, 2023.

Cowles, D. (2007). Membranipora membranaceaĀ (Linnaeus, 1767).Ā Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed September 5, 2023.


I updated this page on September 5, 2023

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