Study

Refuges modulate coral recruitment in the Caribbean and the Pacific

  • Published source details Edmunds P.J., Nozawa Y. & Villanueva R.D. (2014) Refuges modulate coral recruitment in the Caribbean and the Pacific. Journal of Experimental Marine Biology and Ecology, 454, 78-84.

Actions

This study is summarised as evidence for the following.

Action Category

Use settlement tiles made from unnatural materials to encourage natural coral settlement

Action Link
Coral Conservation

Use settlement tiles made from unnatural materials to encourage natural coral settlement

Action Link
Coral Conservation

Use settlement tiles made from unnatural materials to encourage natural coral settlement

Action Link
Coral Conservation
  1. Use settlement tiles made from unnatural materials to encourage natural coral settlement

    A replicated study in 2010–2012 on five fringing reefs off St John, US Virgin Islands (Edmunds et al. 2014) found that the upper surfaces of unglazed terracotta or acrylic settlement tiles were colonized by stony corals when they had refuge holes, but not when they were smooth. No corals settled on upper surfaces of tiles without refuge holes during the study. On tiles deployed August 2010–June 2011 coral density did not differ between upper surfaces with refuge holes (0.97 corals/100 cm2) and lower surfaces (1.08 corals/100 cm2), but on tiles deployed June 2011–August 2012 there was lower density on upper surfaces with refuge holes (0.14 corals/100 cm2) than lower surfaces (1.31 corals/100 cm2). See paper for preferences of different coral species. At five sites off St John (<500 m apart), a cluster of 15 unglazed terracotta or acrylic settlement tiles was attached at 45° to horizontal at 5 m depth, 1 cm above the substrate, using stainless steel studs and a spacer which were attached to rocks with epoxy putty. Tiles were deployed August 2010–June 2011, then replaced and left until August 2012. When retrieved, tiles were cleaned, dried and inspected with a microscope for corals. For each sampling period, authors inspected the lower surface of seventy-five terracotta tiles (15 × 15 × 1 cm) and the upper surface of 20 terracotta tiles topped with acrylic tiles (15 × 15 × 0.6 cm) which had been drilled with holes on the top surface only, and 20 undrilled acrylic-only tiles.

    (Summarised by: Eleanor Bladon)

  2. Use settlement tiles made from unnatural materials to encourage natural coral settlement

    A replicated study in 2010–2012 on three reefs off Lyudao, Lanyu and Kenting islands, Taiwan (Edmunds et al. 2014) found that the upper surfaces of unglazed terracotta or acrylic settlement tiles with refuge holes were colonized by a higher density of stony corals than upper tile surfaces with no holes. Four weeks after deployment, upper surfaces of tiles with refuge holes had a higher density of settled corals (1.6–7.9 corals/100 cm2) than upper surfaces without holes (0.3–1.9 corals/100 cm2) and lower surfaces (0.3–4.7 corals/100 cm2, data is not separated for lower surfaces with or without refuge holes). See paper for preferences of different coral species. Pairs of unglazed terracotta or acrylic tiles (10 × 10 × 1 cm) with a smooth and a grooved surface were stuck together, either with both grooved surfaces facing outwards (refuges) or both smooth surfaces facing outwards (smooth). Off three islands (70–105 km apart), 15–18 pairs of refuge and smooth tiles were fixed a few cm above the substrate at 45° to horizontal using stainless steel bolts at a depth of 5 m. Tile pairs were deployed in March–April (2–3 weeks before coral spawning), off Lyudao in 2010 and off Lyudao, Lanyu and Kenting in 2012, retrieved four weeks later, cleaned, dried and inspected with a microscope for corals.

    (Summarised by: Eleanor Bladon)

  3. Use settlement tiles made from unnatural materials to encourage natural coral settlement

    A replicated study in 2010–2012 on three reefs off Caniogan, Cangaluyan and Lucero islands, Philippines (Edmunds et al. 2014) found that upper surfaces of fibre-cement settlement tiles with refuge holes were colonized by a higher density of stony corals than upper surfaces without holes. Five months after deployment, upper tile surfaces with refuge holes had a higher density of settled corals (1.9–11.4 corals/100 cm2) than smooth upper surfaces (0–1.7 corals/100 cm2) and lower surfaces (0.4–2.8 corals/100 cm2, data is not separated for lower surfaces with or without refuge holes). See paper for settlement surfaces of different coral species. Fifteen fibre-cement tiles (10 × 10 × 1.2 cm) with refuges (drilled with sixty-four 0.5 cm radius holes on each side) and 15 without refuges (smooth) were fixed 1 cm above the substrate at 45° to horizontal using concrete nails at a depth of 5 m on fore-reefs at Caniogan, Cangaluyan and Lucero (11–24 km apart). Refuge and smooth tiles were installed 30 cm apart in February 2012 and retrieved in July 2012. Peak coral spawning was March–May. Retrieved tiles were cleaned, dried and inspected with a microscope for corals.

    (Summarised by: Eleanor Bladon)

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