Intense capture of swarming pteropods by large-polyp corals

Abstract

Snorkeling about an hour after sunrise, November 6 th , 2016, we observed high densities of pteropods (Creseis acicula (Rang, 1828); visually estimated >3 pteropods l-1) swarming in the waters above the shallow coral reef of Eilat, Israel. Many pteropods were captured by massive corals with large polyps (Merulinidae: Dipsastraea spp., Favites spp., Platygyra sp. and others). Some of the captured pteropods exceeded one cm in length. In some corals, we observed single polyps ingesting up to three pteropods (Fig 1 A, B). Empty shells were found on the bottom beneath the corals. Neither captured pteropods nor empty shells were found in or around corals with small polyps, including Acropora spp.,

Physiological and morphological plasticity in Stylophora pistillata larvae from Eilat, Israel, to shallow and mesophotic light conditions

“…Smaller calyx diameter is also present in adult colonies of deep relative to shallow colonies of S. pistillata 20 ; calyx diameters of primary polyps in this study were comparable to those measured for adults of this species. 20 Smaller calyxes (polyps) may be suggestive of reduced feeding potential, different prey sources, or unrelated to feeding since such a link between calyx size and feeding is seldom reported in corals 62 , 63 but see 64 for a qualitative observation of differential prey capture between corals with large versus small polyps. Mesophotic coral colonies typically have a higher dependence on heterotrophy rather than translocated photosynthates for energy, 18 , 19 , 20 , 65 , 66 which may be the result of increased feeding effort rather than a morphological adaptation.…”