Vertical distributions of late stage larval fishes in the nearshore waters of the San Blas Archipelago, Carribean Panama

Abstract

Light traps were used to describe the vertical distribution of late larval stages of reef fishes in the San Blas Archipelago during three successive new moon periods. Traps were deployed in the lagoon and at an exposed site on the outer reef edge. At each site, two traps were anchored at the surface and two traps just above the bottom. Most families of reef fishes that were abundant in catches displayed clear patterns of depth preference. The larvae of gerrids, pomacentrids and lutjanids were predominantly captured in shallow traps. while gobiids, labrids, apogonids and blenniids were usually collected in deep traps. Studies that used lights to aggregate and collect larval fishes display marked differences in the composition of catches between the Great Barrier Reef (GBR) and the Caribbean. In order to determine whether such results were due to biases inherent in different sampling methods, or to locality-specific patterns of larval behaviour, we simultaneously deployed light traps and dip-netting around lights during three new moons in the San Blas Archipelago. We found that these sampling techniques collected differing components of the larval fish assemblage from the same water mass. However, there remains good evidence for the existence of locality-specific responses to light in older larval stages, suggesting that broad generalisations about patterns and causes of vertical distributions may be difficult to achieve