Fig 1.
Life history strategy of broadcast spawning corals, from the epipelagic release phase of sperm and eggs in mass spawning to the benthic stage of larval settlement and recruitment into the population.
Inset photographs are representative images of neutral red and Nile blue stains on larvae (colored vs. control unstained larvae in white) and recently settled life history phases. Clip art has been modified from [22] under a Creative Commons Attribution (CC BY) license. Images (adult, larvae, settler) supplied by authors.
Fig 2.
Probability of larval survival and settlement for two species of coral exposed to four stains at different concentration levels and incubation times.
For probability of settlement, the filled proportion of the circle indicates the proportion of surviving larvae, and colors indicate the strength of the larval stain at each stage (larval stage and settled larvae; inset key indicates none, light, medium, or strong staining). Letters in bars indicate pairwise differences in probability of larval survival for A. spathulata. When a p value exceeds α = 0.05, then two means have at least one letter in common. Images supplied by authors. Data underlying this Figure can be found at https://doi.org/10.25919/4rry-xg84.
Fig 3.
Representative images of free-swimming and newly metamorphosed larvae (Nile blue, unstained, neutral red) from A. anthocercis, P. sinensis, C. aspera, and mixed Nile blue and neutral red stained D. favus larvae.
White scale bars = 1 mm. Images supplied by authors.
Fig 4.
Probability of larval survival and settlement for four species of coral exposed to neutral red and Nile blue stains at different concentration levels and incubation times.
For probability of settlement, the filled proportion of the circle indicates the proportion of surviving larvae. Differences in larval survival between treatments shown against controls (dash line), where no mortality was observed (100% survival). Inset notation for probability of settlement indicates significant differences from control within each species at an α of 0.05 (ns = no significant difference, * = p < 0.05, ** p < = 0.01, *** = p <0.001). Images supplied by authors. Data underlying this Figure can be found at https://doi.org/10.25919/4rry-xg84.
Fig 5.
Field validation of larval staining: capture of wild-sampled coral spawn slicks showing high diversity of developing coral embryos, lab-based staining using Nile blue (1,000 mg l−1 concentration for 60 minutes), and field deployment of competent stained and natural (unstained) larvae for detection on reef substrates.
Images supplied by authors.