Abstract:
Sombrero Island is the most distant landmass belonging to Anguilla and an important fishing ground for many local fishers. To date, although some biodiversity work has taken place there, no quantitative benthic habitat surveys have ever been conducted. With its designation in 2010 as a Nature Reserve Marine Park, this lack of information became more significant. Taking the first steps to fill this knowledge gap, the Department of Fisheries and Marine Resources undertook a rapid assessment of the area in 2015 using an underwater towed video array technique developed recently by researchers on neighbouring islands. Analysis of over one hundred screenshots revealed the most common habitat type were sand flats (48%) followed by pavement reef (24%), rubble areas (24%), and rocky reef (8%). The most common benthic cover after sand was turf algae (30%), followed by Sargassum and/or large macroalgae species (21%). Sponge cover was recorded as 3%, with live hard coral cover low at less than 0.5%. Seagrass or Acropora palmata were not observed along any of the transects. The structural complexity was primarily categorised as low and/or sparse relief. Although this was a rapid assessment and as such limited in scope, it does confirm the viability of the visual census technique used, and how with some slight methodological changes it will become even better suited to surveying reef habitats. It is also hoped that this work will pave the way for further, more expansive, offshore fishing ground habitat assessments essential for making management decisions within the fisheries sector. It is recommended that these future habitat assessments are combined with fish stock assessments in order to give managers all the information necessary.
