On-shelf larval retention limits population connectivity in a coastal broadcast spawner
Boundary currents are often considered to be the main drivers of connectivity among populations of coastal animals. Teske and co-workers combined population genetic data from a southern Australian snail that has a very long planktonic larval duration with simulations of connectivity based on oceanographic data. They show that most propagules never reach the region's boundary currents, and few of those that do will return to the coast to settle. Retention of larvae on the continental shelf results in a strong range-wide correlation between genetic and geographic distance, a pattern that is usually only found in species with much lower dispersal potential.