Shaggy sea hares photographed from the surface.
Photo Marie.
Another one actually sticking out of the water.
Photo Nicole Masureik
Individuals photographed underwater in Knysna.
Photos Guido Zsilavecz
This species is known to have population explosions, with large numbers appearing suddenly where previously there were only a few individuals. SURG has observed this in Cape Town's Long Beach area (next to Simon's Town) in August 2007 (see the News 2007 section). In Cape Town these sea hares are otherwise virtually never seen. In Knysna lagoon we had seen them on about all dives over many years at Thesen's Jetty, a few individual here and there, but a visit in October 2008 showed a clear population exposion (see the News 2008 section.) Now, two contributors, Marie and Nicole, individually submitted observations of high numbers in nearby Sedgefield lagoon. Here is their experience:
Marie: I was in Sedgefield this weekend and as we walked next to the lagoon I noticed these sea hares in the water. I was very surprised as we have been visiting Sedgefield many times over the past years (my parents used to live there), but have never noticed these before in the water!
They were in the shallow water feeding. It was very interesting to see how they ingested the sand and then filtered it out through an opening on their backs.
Nicole: I was stunned when I saw these sea hares for the first time in Swartvlei lagoon and river in Sedgefield over Easter now. I've never seen them in the area before. What I found interesting is that they were out and about at midday, in broad sunlight with no covering of reeds or other material.
For more details on this species, see "Nudibranchs of the Cape Peninsula and False Bay" available directly from SURG or better dive and book stores in Cape Town.
Nudibranchs of the Cape Peninsula and False Bay, G Zsilavecz, 2007
Nudibranchs of Southern Africa - a guide to the opisthobranch molluscs of southern Africa, T. Gosliner, 1987