*Bonus* Observation of the Week, 6/19/18

Our Bonus Observation of the Week is this “mating frenzy” of Ringed Goniobranch nudibranchs, seen off of Israel by @barchana!

Sometimes we want to highlight several observations that have been posted to iNaturalist, so in addition to the Brown Bullhead with a rattlesnake meal, we’re writing a blog post about stunning “mating frenzy” of nudibranchs you see above, posted by Dani Barchana.

Dani is a veterinarian and lecturer with the the Hebrew University Of Jerusalem and The School Of Marine Sciences in The Ruppin Academic Center, where he specializes in marine mammals. He has always loved nature, and explains “so my profession and hobbies (mountain biking, diving and photography) are just [about] being there and observing.”

“We are fortunate in Israel to have beaches to the Mediterranean and to the Red sea.” says Dani. And because of this, he was able to witness the Lessepsian migration, which is the movement of flora and fauna between those two seas via the Suez Canal. “We used to see them only at the Red Sea but they were observed, for the first time,  in the Israeli Mediterranean cost on 2006 and now they are [the] most common nudibranch in our beaches,” says Dani. “They almost disappear at winter but when spring comes, they are everywhere and for the last few weeks they [have been] mating and laying eggs all over. The sight of a few specimens together is not rare, though so many together is not so common.”

Like other nudibranchs, Ringed Goniobranchs are known as “sea slugs,” and are marine gastropods that move around on a slimy foot. “Nudibranch” is derived from Greek and means “naked gills”. These feathery gills protrude from the dorsal side of the slug and are, in this species, encircled by one of the purple “rings” on the dorsal side. The rhinophores, or sensory organs, are found inside of the other ring. As Dani noted, Ringed Goniobranchs form groups when they are mating, and they are also hermaphroditic.

With photography being one of his hobbies, Dani (above, photo by Ilan Ben Tov) has a large backlog of fantastic photos, and says

I was asked several times by biologists to provide pictures of different species of animals to their articles, books and lectures, since my web albums are biologically oriented (arranged by species). When I discovered iNaturalist, I thought I can help in a more organized way to the scientific community.

- by Tony Iwane (As English is not Dani’s primary language I also did some light editing with his quotes.)

- Some great nudibranch footage here, including a group of Ringed Goniobranchs and another laying its eggs in a spiral pattern. 

- Some nudibranchs practice...interesting...mating techniques

Posted by tiwane tiwane, June 19, 2018 23:53


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