Bron, P.S.

Student Report 

Coral reefs are one of the most important ecosystems in the world, in terms of both biological diversity and economy. These ecosystems are under a great amount of threats (e.g. climate change, pollution, coastal development and overfishing), which can lead to reef degradation and decrease of three-dimensional structure. In the worst-case scenario this can result in coral-algal phase shifts, this is in particular occurring when herbivorous fish are over exploited. The aim of this study was to investigate possible relations between herbivorous fish groups (Acanthuridae and Scaridae), coral recruitment and growth rates, on three different types artificial reefs on Saba and St. Eustatius.

For more information contact Alwin Hylkema: alwin.hylkema@hvhl.nl

While the scarcity of up-to-date data on beach litter contamination in the Caribbean has been stressed in several recent studies, we here point to the even greater paucity of published work on litter in mangroves and on the shallow tropical seafloor. During collection of baseline data on beach litter contamination on the Southeastern Caribbean island of Bonaire we also collected preliminary data that may serve to highlight the need for further studies on these largely neglected litter issues.

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Marine litter contamination is a wide-spread problem and considered to be one of the most serious threats to sustainable use of the region’s marine and coastal resources. Mangrove litter and shallow submerged litter contamination figure significantly in Bonaire and we have made practical recommendations to help address these problems in a separate report to government. In presenting this synopsis here, we aim to draw scientific attention to these largely neglected facets of the litter problem and hope to see further studies to assess the extent of these problems in the Wider Caribbean.

Data on beach debris and tar contamination is provided for 21 natural beach sites in Bonaire, Southeastern Caribbean. Transects amounting to a combined length of 991 m were sampled March–May 2011 and a total of 8960 debris items were collected. Highest debris and tar contamination were found on the beaches of the windward east-coast of the island where geometric mean debris concentrations (± approx. 70% confidence limits) were 115 ± 58 items m-1 and 3408 ± 1704 g m-1 of beach front. These levels are high compared to data collected almost 20 years earlier on the nearby island of Curaçao. Tar contamination levels averaged 223 g m-1 on windward beaches. Contamination levels for leeward west-coast beaches were generally two orders of magnitude less than windward beaches.