Bioerosion and sediment ingestion by the Caribbean parrotfish Scarus vetula and Sparisoma viride: Implications of fish size, feeding mode and habitat use

摘要: Erosion rates and sources of sediment ingested were quantified for the 2 most abundant parrotfish species on a leeward fringing reef Bonaire, Netherlands Antilles: Scarus vetula Sparisoma viride. Direct estimates erosion by different size classes obtained from daily feeding grazing scar frequency, volume substrate density. Foraging preference distribution fish used to examine patterns bioerosion at spatial scales: zones individual substrates grazing. Sediment mass provided an independent check rates, was partitioned according source. S. vetula, employing scraping mode, removed less material grazed than similar sized viride, which forages excavating substrate. increased strongly with in both species. The (indigestible) carbonate derived epilithic algae accounted all juvenile fish. In adult fish, proportion freshly eroded size. adults these large scarids over determines rate scale. highest bioerosional occur shallow (ca 7 kg m(-2) yr(-1)), they decrease depth. Parrotfish foraging preferences, effects food type skeletal density scars, cause differences small infested boring low density, while high-density covered crustose corallines undergo lower rates. Living coral is rarely eaten scarids, largely escapes