Abundance and biomass of the parrotfish Sparisoma cretense in seagrass meadows: temporal and spatial differences between seagrass interiors and seagrass adjacent to reefs

Abstract

Seagrass habitats are relevant for numerous nearshore fish species, particularly as nursery grounds. Seagrass meadows are often interspersed with other habitats, what can alter the distribution and abundance of seagrass ichthyofauna. This research aimed to determine whether there is a change in the abundance and biomass of the parrotfish, Sparisoma cretense, in seagrass meadows (Cymodocea nodosa) with varying proximity from rocky reefs, specifically seagrass interiors (>200 m away from reefs) vs. seagrass adjacent to reefs (<10 m away). Sampling was undertaken using a seine net and underwater visual census through an entire annual cycle. Adults were predominantly observed in seagrass adjacent to reefs, which seem to be restricted to incursions of large-sized parrotfish from adjacent reefs. Juvenile abundance did not significantly differ between seagrass interiors and seagrass adjacent to reefs; however, juvenile biomass was greater in seagrass meadows adjacent to reefs compared to those far away from reefs. This pattern was consistent through times for both sampling techniques. These results suggest a transition of juvenile parrotfish from seagrass interiors to seagrass near reefs, so juveniles are located in the vicinity of their adult habitat, i.e. rocky reefs.