Trace metal incorporation in otoliths of a territorial coral reef fish (Abudefduf saxatilis) as an environmental monitoring tool

Abstract

Trace metal levels in the otolith external layer of newly Abudefduf saxatilis (Pomacentridae) recruits, a common fish of the Caribbean coral reef, were examined as an indicator of recently occupied habitat from the most important coral reefs of the east of Venezuela (Mochima National Park and La Tortuga Island). These otoliths were analyzed trough an Energy-dispersive X-ray spectroscopy (EDS) fixed to scanning electron microscopy (SEM). The five trace metals analyzed (Cd, Cu, Hg, Pb and Zn) were found at external layer of most evaluated otoliths at all localities, in which %weight of Pb/Ca and Hg/Ca showed the highest values. These results show the bioavailability of evaluated metals at Mochima National Park and La Tortuga Island, and their significant spatial variations on otoliths make evidence of different concentration of Cd, Hg and Pb in water and/or sediments of these locations.

Keywords

• Otolith
• heavy metals
• SEM-EDS
• coral reef fish