Publisher :
Place of publication :
Publication year : 2009
Thematic : Species
Language : English
Note
Global levels of available methylmercury (MeHg) in aquatic ecosystems have increased
dramatically over the past century. Recent findings in temperate North America have shown that biological
mercury (Hg) hotspots exist, and these hotspots can be related to local emission and effluent
sources. Life history traits of the goliath grouper Epinephelus itajara place it as a species at high risk
of adverse effects from environmental Hg loads. Muscle Hg analyses for 57 goliath groupers sampled
in southern Belize reveal that 40% exceed United States governmental advisory criteria for human
health; all individual grouper exceeding these criteria were >55 cm total length. People, particularly
from coastal areas in southern Belize, commonly consume goliath grouper. The regular consumption
of goliath grouper by sensitive groups of people, such as pregnant women, should be closely monitored,
particularly in biological Hg hotspots. Stable isotope analysis for ä13C and ä15N in goliath
grouper indicates a broad prey base with a relatively high trophic status. Through biomagnification
and bioaccumulation of MeHg, older individuals are therefore at greatest risk of physiological
impairment, particularly when performing complex and coordinated behaviors, such as those associated
with spawning aggregations. Potential adverse effects of MeHg loads on goliath grouper,
including predator avoidance, impaired growth rates, and lowered reproductive success, warrant
investigation. This is particularly urgent for the critically endangered goliath grouper because of
recent range-wide population declines, loss of spawning aggregations, and our findings, which present
compelling evidence that tropical marine ecosystems are sensitive to Hg inputs.
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Keywords : Cuora trifasciata
Encoded by : Pauline Carmel Joy Eje
