Uncovering the Secrets of BIOT's Manta Population

January 2020

The British Indian Ocean Territory (BIOT) offers researchers a near pristine study site. With virtually no tourism or fisheries, the population of mantas is theoretically as close to it's natural state as possible.

Joanna Harris is the project leader for the Chagos Manta Project and is currently undertaking her PhD studies at the University of Plymouth. Her project is focused on one of the least accessed populations of manta rays in the world. One of the atoll in the BIOT Archipelago, Egmont Atoll, appears to be some what of a manta hotspot. Working with the researchers from the University of Plymouth, Joanna is hoping to find out why sites like Egmont are so well suited for manta ray aggregations.

During the expedition, Joanna and myself were collecting photo IDs of the manta rays we encountered, deploying acoustic tags on 20 different individuals, and collecting tissue biopsy samples. The tags will give us more information about the manta ray’s use of Egmont atoll over a long period. We were also collecting plankton samples from feeding sites in order to work out prey density threshold and understand more about the food availability. All of this data will be complimented by the oceanographic data collected by the University of Plymouth’s long term data recorders.

If you missed part 1 of the BIOT Expedition video, be sure to check the ‘Videos' section of the Cyclone to see all the other exciting research undertaken on the cruise by the team from the University of Plymouth.