Coral reef fish larvae: patch size estimation and mixing in the plankton

The daily pattern of settlement of larvae of the bluehead wrasse, Thalassoma bifasciatum, onto a number of coral reefs was reconstructed with the daily otolith increment aging technique. Larvae settled simultaneously onto reefs within an area of about $1,000 km^2$. The planktonic patch size of bluehead wrasse larvae is inferred to be at least 46 km wide. Larvae settling onto a reef at the same time were not the same age, indicating that planktonic dispersal results in mixing of cohorts of larvae.