Micropredators lurk among the seaweed

Argentinean and Australian Museum scientists have discovered a guild of micropredators living on seaweeds in the coastal waters of southern New South Wales.

Tiny but agile isopod crustaceans (suborder Asellota) that live on seaweeds in the Batemans Bay region are the subject of a biodiversity study conducted by Dr Brenda Doti, recipient of an Australian Museum Visiting Research Fellowship and Dr Buz Wilson. This project is part of a collaboration with Dr Alan Millar, a marine phycologist (seaweed specialist) at the Royal Botanic Gardens Sydney, who led diving research trips to southern NSW funded by the Hermon Slade Foundation.

Many studies of animals that live on marine macroalgae capture only large species, missing the many tiny inhabitants that comprise most of the diversity on these plants. The Museum-based study used a fine screen to collect specimens, thus opening a window into life at the small scale. As a result, Doti and Wilson have identified 32 species isopod crustaceans living on marine plants, of which 30 are new to science.

The researchers were interested in determining why these asellote isopods live on the plants. Do they feed on them directly or are they present for other reasons? Examination of their gut contents revealed that the isopods are micropredators that feed on even smaller worms and crustaceans or on many sessile (attached) invertebrates like sponges or bryozoans that live on marine algae.

Doti and Wilson's study continues with the description of 3 new species nearing completion. These species belong to three isopod genera found elsewhere in the world but currently unreported for Australia.