RP16 Biomonitoring
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(GOL-1117-818085) Characterization of Esterases in Different Organs of the White Grunt (Haemulon plumieri) for their Use as Biomarkers in the Mesoamerican Barrier Reef System.

Alpuche-Gual, L¹, Gold-Bouchot, G¹, ¹ CINVESTAV Unidad Merida, Merida, Yucatan, Mexico

ABSTRACT- The Mesoamerican Barrier Reef System is considered the second longest barrier reef in the world. It is an area with a high biodiversity, both in terms of species and habitats, which is threatened by development of coastal areas. The white grunt (Haemulon plumieri; Lacepede, 1801) has been chosen as a bioindicator species for the regional monitoring program; it is a fish of tropical and warm-temperate waters that is distributed in the Atlantic coast from Virginia to Florida, along the Caribbean, and to the south of Brazil. The biological, physiological and ecological information that exists on this organism is scarce, and neither has it been studied from the ecotoxicological point of view. The objective of this work is to characterize the activities of cholinesterases and carboxylesterases in brain, liver, muscle gills, eye and spleen, and to determine if there any differences in the activities with respect to size. Twenty five fish were collected in a place near a fishing village, without agricultural activity, and were taken alive to the laboratory where they were sacrificed and brain, liver, muscle, gills, spleen and eye were excised; the gonads were preserved to determine sex and maturity. Cholinesterase activity was determined by the Ellman modified technique, carboxylesterase activity by the method of Mastropaolo and Yurno, and protein according to Lowry. Results indicate that cholinesterase activity is highest in the liver, followed by the brain and muscle; the gills, eye and spleen had a very low activity, and are inadequate to determine variations caused by pollutants. Only the liver presented a measurable carboxylesterase activity, and the other organs had very low activities of this enzyme. There were no significant correlations between correlation weight or total length with esterase activity, and thus size is not a factor that affects esterase activity in the of the white grunt.

Key words: Esterases, MBRS, White Grunt, Monitoring