Coral in South Moresby

By Michael Reuscher

During our first dive in South Moresby, an area known as coral habitat, we fulfilled the main goal of our expedition: Finding Coral!

The sea fan of the genus Swiftia is not a single specimen but a colony of polyps. The picture shows a close-up of a single polyp. Swiftia catches its food, little planktonic animals and larvae with its eight tentacles that are armed with stinging cells. These cells shoot out tiny venomous harpoons with an acceleration up to 40,000 times greater than that of the Earth’s gravitational field.

Attached to the corals we found a family clan of skeleton shrimp belonging to the amphipod family Caprellidae. These brittle animals are known for their brood care. We found the mother and some twenty juveniles on the coral, and five more tiny specimens on the mother’s “tail”. The skeleton shrimps catch their prey out of the water column.

Three different brittle star species lived either on the coral or the stone where the coral settled on. The close-up shows the smallest of the three specimens on the arm of one of the bigger ones. Brittle stars were very abundant in South Moresby. They have a wide variety of feeding mechanisms. Some feed by holding their five arms in the water to catch their food out of water, others feed on detritus, and some feed on mucus produced by corals.

All these critters were found on a little stone maybe 10 cm long, forming a little microcosm. One of billions in the deep sea off British Columbia.