Meeting a strange sea slug (Akera bullata).

Images and text by Erling Svensen

My brother Rudolf and I was on a diving job in the fjord of Hardanger this winter. We dived on several locations and had already done two dives when we came to something that looked like a rather uninteresting dive. It was a narrow bay with a beach often used by the local people. The echo sounder showed very soft mud. Well, the job had to be done even it is was going to be a boring dive.

We jumped off the boat and landed on flat soft mud 15 metres below the surface. There were not much to see. A couple of bristleworms and sea stars was all we could spot on the soft sea-bed. After 10 minutes we came to a slope covered with small algae. Among the algae were hundreds of a strange sea slugs I, although I have done more than 3000 dives and 35 years of diving, could not recognice.
It was a sea slug called "ballsneil" in Norwegian. The scientific name is Akera bullata, and it have an inner thin shell which is covered with a violet or brown mantlewith white dots. The head looks like a small dragon and it really was a fascinating creature.
I have read about this sea slug in many books and always wanted to meet one, so I guess this was my lucky day. The "ballsnails" was up and visible to mate this day. Normaly they are digging their wey through the muddy bottom.

Erling

Fakta fra Sea Slug forum på engelsk:
Akera bullata is quite similar in shape to Akera soluta from the Pacific. They are very primitive Sea Hares [see Akeroidea Fact Sheet] and have a bubble-shaped external shell, an elongated neck-head region, and parapodia which fold over on each side to partially enclose the body. They spend most of their time crawling or burrowing in fine mud on sheltered shores and bays, but at time form swimming swarms, often in quite large numbers. They swim rather awkwardly with their heavy (shelled) end hanging down, rather like large heavy beetles flying. Can grow to 5 - 6 cm in length.

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