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