Feeding & breeding in Gymnodoris ceylonica

September 9, 1999
From: Scott Johnson

Hi Bill,

Gymnodoris ceylonica is a species that seems to occasionally engage in mass movements into shallow water to spawn. My first encounter with the species was at Enewetak Atoll in September of 1981, when I came across six specimens crawling up a sandy lagoon slope at depths of between 6 and 15 meters. Three days later, I returned to the same area. This time I counted 80 individuals in a 10 minute swim that dropped as deep as 25 meters on the slope. All were crawling upward toward shallow water. Up shallow, at a depth of about 2-4 meters, these animals were depositing egg masses on just about everything. It looked like there were hundreds of egg masses. When not spawning, they were busy eating Stylocheilus (bottom pics). I saw this happen several times at Enewetak in the early 80s, but have not observed it at Kwajalein over the past 11 years.



Johnson, S., 1999 (Sep 9) Feeding & breeding in Gymnodoris ceylonica. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1289

Thanks Scott,
After these great photos it seems a bit churlish to ask if you have any egg-mass photos to share.
Bill Rudman.

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