TRACE METALS IN LITOPENAEUS VANNAMEI BROODSTOCK FROM ECUADOR AND EL SALVADOR


A. Alcivar-Warren, K. Astrofsky, J. Alcivar, R. Henry, D.M. Meehan

Abstract:

Natural populations of L. vannamei shrimp are threatened by loss of habitat, pollutants and diseases. These environmental pressures may be impacting the genetic diversity and disease resistance characteristics of L. vannamei and other marine species. To develop a sustainable shrimp aquaculture industry and protect wild shrimp populations and their habitat, baseline information on presence of pollutants, prevalence of diseases and genetic diversity is needed. Working towards this goal, we have begun development of a database of pollutants (heavy metals, PCBs, PAHs) present in L. vannamei and P. monodon. The aim of this study was to examine the trace concentrations of 15 metals in L. vannamei broodstock. L. vannamei broodstock from Ecuador and El Salvador were maintained under similar environmental conditions in a culture pond for breeding purposes. Ten samples from each of three regions of Ecuador (Esmeraldas, Manabi and Guayas provinces) and from El Salvador (n=8) were analyzed for: aluminum (Al), antimony (Sb), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), potassium (K), selenium (Se), silver (Ag) and vanadium (V). All 15 metals were present in adult L. vannamei. The range of trace concentrations, pg/g (ppm) on a fresh weight basis, varied among samples within and among sites. The concentrations were as follows: Al (0.2 to 8.0), Sb (0.004-0.009), Ba (0.04-0.77), Cd (0.046-1.066), Cr (0.22-1.48), Cu (3.48-22.69), Fe (2.020.00), Pb (0.006-0.195), Mn (0.12-0.74), Hg (0.014-0.250), Ni (0.007-0.357), K (2458-3383), Se (0.18-0.53), Ag (0.0140.128) and V (0.12-0.33). For each metal, the mean concentration was calculated and used to rank the regions from highest to lowest. Analysis of all 15 metals showed that shrimp from Guayas ranked first in the number of metals with highest concentrations (10 out of 15), followed by El Salvador (4 out of 15), and Esmeraldas (1 of 15). Broodstock from Manabi ranked the lowest (9 out of 15) in trace metal concentrations. Shrimp from El Salvador had the highest trace concentrations for four (Cd, Hg, Cr, Ni) metals of great health interest. Some of the heavy metal concentrations reported here have the potential to impact the genetic diversity and function of reproductive and immune response systems of L. vannamei. A monitoring system based on habitat status, genetic structure and pollutants load in wild shrimp will be initiated in order to conserve the shrimp resource. This information should contribute to the development of a sustainable aquaculture industry

(Department of Environmental and Population Health, Tufts University, School of Veterinary Medicine, North Grafton, MA 01536 USA)

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