Blending In - Video of Lacy Bryozoan & its Inhabitants in the Lembeh Strait

Please "like", share, comment or view this Lembeh Strait muck diving video on YouTube.

The lacy bryozoan, Triphyllozoon inornatum, was usually overlooked by divers until diver Graham Abbott noticed a tiny goby living amongst them at Ambon in Indonesia in 2013. He alerted Ned and Anna DeLoach, the underwater photographers and marine biologists, and they subsequently found the same species of goby in these bryozoans, along with other cryptic critters. That story can be read on the excellent Blenny Watcher Blog.

On a trip to the Lembeh Strait in 2015 I was lucky enough to spot the same goby at the dive site Jahir. It shelters in the natural tunnels created by the bryozoan and blends in perfectly against the pale background. The goby is only about 1cm long. Ichthyologists Gerry Allen, Mark Erdmann, and N.K. Dita Cahynai described the goby in 2016 and assigned the name Sueviota bryozophila. Eye abnormalities are quite common amongst reef fishes. This particular fish had a defect to it's right eye, which was much smaller than the left one.

At Makawidey I spotted the small porcelain crab, Pachycheles garciaensis, sitting on top of a bryozoan. Again, it's mostly white colour helps it avoid detection.

Finally at Aer Bajo, we found a bryozoan hosting an undescribed species of snapping shrimp, Synalpheus sp.. Snapping shrimps, also known as pistol shrimps, have asymmetrical claws. The larger one can close with great speed, creating a small cavitation bubble. As the bubble collapses, a loud popping sound is emitted which stuns passing prey. Much of the crackling often heard on a reef is due to this family of shrimps.

Colonies of bryozoans are rooted to the substrate and vary greatly in form. They filter plankton with their tentacles and many, such as this one, secrete a calcerous skeleton. Because of these similarities, they are often mistaken for corals, but they actually belong to a completely different phylum. Each individual animal in a colony is rarely larger than a millimeter in size.

The tiny stalks with white ends visible on the bryozoan are stinging hydroids in the Zanclea genus, possibly Zanclea exposita. Presumably the critters symbiotically use the hydroids' sting in their own defence.

The video was shot by Nick Hope with a Panasonic GH4 in a Nauticam NA-GH4 housing. I used an Olympus M.Zuiko ED 12-50mm f3.5-6.3 EZ lens and 60mm f2.8 macro lens.

Thanks to dive guides Hiros and Frankie of YOS Dive Lembeh for finding these critters.

Nick Hope