Re: Notarchus indicus at Eilat

February 17, 2006
From: Binyamin Koretz

Concerning message #13325:

Dear Bill,

In your earliery message you referred to a report from the 1970's concerning an observed population explosion of Notarchus indicus in Eilat. It's happening again right now!

In 2005, following a big influx of algae, we saw a moderate number of individuals over the course of the spring (March, April, May), all of them at night, and only at one dive site with a lot of thick seagrass around the sporadic coral heads. Then none for about 8 months, although we dived this site at night every week or two. As recently as 4 weeks ago, we still saw none. Then the algae started to return, and 2 weeks ago we counted 4 in one dive. Last night we saw dozens, perhaps hundreds, in one dive.

The one in front of my hand [lower photo] had just tumbled in front of me as I was finning - in its peculiar swimming motion. Another one crawled blithely across the back of a tiny (7 mm) Sclerodoris tuberculata. And among the many pairs you could see the range of coloration from creamy white to bright amber.

Locality: Eilat, Satil Area, 22-24m, Israel, Red Sea (Gulf of Eilat), 11 February 2006 (night), sea grass and patch reef. Length: up to 3 cm. Photographer: Binyamin and Shulamit Koretz

Best regards
Binyamin Koretz

Koretz, B., 2006 (Feb 17) Re: Notarchus indicus at Eilat. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Binyamin,
Their swimming behaviour must make them the clowns amongst the Sea Hares. I look forward to further observations
Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Feb 17). Comment on Re: Notarchus indicus at Eilat by Binyamin Koretz. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


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