Abstract

Over the past decade. mass accumulation and decomposition of pelagic sargassum along the coasts of Eastern Caribbean islands has resulted in negative socio-economic and ecological consequences. During influx events. mats approaching the coastline begin to break down and once beached result in management challenges for fisheries. tourism and nearshore coastal ecosystems. In- water harvesting has been suggested as a possible solution to minimise the impacts associated with beached sargassum. However. protection of the biodiversity associated with sargassum mats remains a primary concern. This study aims to examine spatial differences in the abundance and diversity of sargassum associated fauna at various distances from shore. and whether this is affected by changes in the species composition of sargassum influxes. Using a combination of net sampling and underwater video footage. biodiversity assessments were conducted inshore (< 50 m). mid-shore (50 - 500 m) and offshore (500 - 1000 m) from May to July 2021. Preliminary results indicate that while a variety of epiphytic and clinging fauna are abundant within inshore and mid-shore environments. macrofauna (valuable economic species) appear to have abandoned the mats this close to shore. Thus. in-water collection from inshore or mid-shore may very well prove to be an appropriate and ecologically sustainable management strategy to prevent significant shoreline strandings of the seaweed and/or to harvest fresh sargassum for use.

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