Sakuraeolis enosimensis

Images courtesy of Jan Kocian
Lagoon Point, Whidbey Island, Washington

Sakuraeolis enosimensis (Baba, 1930)

Lucky find - Jan sent out this photo with a Thanksgiving Day wish. It struck me that the ID might be questionable. I called it Sakuraeolis enosimensis (Baba, 1930), not Hermisenda. Jan's reply - "Well, that is a surprise. It did look a little bit odd, but since the Hermissenda has such a reputation of being the bully in our waters, I went with that assumption when I found it on top of the hapless Dirona."

Bill Rudman reports on his Sea Slug Forum that - "Firstly, quite a few glaucid aeolids are quite aggressive, feeding on a wide range of nudibranchs, including their own species. I think Hermissenda crassicornis is the species whose feeding behavior has been most studied." Jan's photo verifies this behavior for sure.

I first reported Sakuraeolis on this coast from San Francisco Bay in my 1982 paper. It has since become a well established species there and may be the second most common species in the bay.

Jan's observation adds to the species geography here, as a disjunct locale, as we have no sightings between San Francisco and Puget Sound.

Dr.Baba described this species from specimens collected by aspiring marine biologist and the Emperor of Japan, Emperor Hirohito. His specimens were colleted in Enosima, Japan, near Sagami Bay and originally placed the species in the genus Hervia. Sakuraeolis enosimensis has a long, slender body, with the tail forming about 1/4 of the body length. Its oral tentacles are long, slender and tapering. The anterior corners of the foot are extended to form horn-like projections. The rhinophores are smooth and shorter than the oral tentacles. The cerata rise from 6-8 arch-shaped pads, in 2-3 rows, except for the posterior two arches, which bear a single row of cerata. The cerata are simple, smooth, and dense, with the longest, in the mid-dorsal region, reaching up to one-half the body length. The animal can reach 45 mm in length, but is more usually 25-30 mm. The color is highly variable, but the basic color of the body is translucent yellow. Sometimes, there are yellow-orange speckles on the head. The liver and its branches usually range from yellow-orange to reddish-brown, but can sometimes be green. The oral tentacles and the tail are marked with an opaque white mid-line, while the rhinophores and cerata have white tips, and the head is also speckled with white.

I sent specimens to Dr. Baba back in the 70's asking for his opinion and he returned these amazing water color drawings OneTwo Three of the dissected specimen with confirmation of its identification. Dr. Baba's passion for the animals (see (Bertsch, 1993) is reflected in the fine detail of his drawings. Remember, this is before scanning electron microscopes and protein and DNA sequencing.

Thanks Jan for adding to our knowledge, both geographically and biologically, of this beautiful species.


Baba, K. 1949. Opisthobranchia of Sagami Bay: Collected by His Majesty the Emperor of Japan. Iwanami Shoten, Japan.

Behrens, D. W. 1982. Sakuraeolis enosimensis (Baba, 1930) (Nudibranchia: Aeolidacea) in San Francisco Bay. The Veliger, 24(4): 359-363.

Bertsch H. 1993. Japanese contributions to Opisthobranch research with special reference to Tako Abe.Iwao Tia\Iatani,and Kikutaro Baba.
Abstracts and Proceedings of the Annual Meeting Held at Asilomar Conference Center Pacific Grove, California 30 June - 3 July 1992 BA

Dave Behrens
Sammamish, WA 98074
Dec. 2019
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Jan Kocian on location

I was born in landlocked Czechoslovakia, but diving became my love early in life, getting my certification in the fresh cold waters of old quarry, before wet suits were available to the diving public behind the " Iron Curtain ".

After emigrating from there in 1968, the sea stayed close to my heart. I worked on research ships in the Pacific, enjoying the warm waters of the tropics for many years.

Not until I retired to Whidbey Island in Washington State I started to pay closer attention to the smaller creatures of the underwater world. And what a wonderful realm it is. Combining wide angle shots with closeups, trying to show the environment in which the animal lives.

My camera rig consists of Olympus M1MkII in Nauticam housing, Sea&Sea YS-D2J strobes, and Olympus TG-5 in Olympus PT-058 housing for the closeups.

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As usual Jan is being very modest about how he "emigrated" to the United States. Part of the his journey involved a horrendous swim from Yugoslavia to Italy! You will need to talk to Jan in person to realize what a perlious undertaking that was!

Attention all you Sluggers, and you know who you are!

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