3. Toxic Effects of Selenium in Fish
48
FIGURE 3.6. One of the most common and outwardly visible teratogenic effects
of selenium in Belews Lake fish was dorso-ventral spinal deformities (kyphosis and lordosis), shown here in mosquitofish (Gambusia affinis).
Ecological Implications
Insidious Mode of Toxicity
Selenium poisoning in fish can be "invisible" because the primary point
of impact is the egg, which receives selenium from the female's diet
and stores it until hatching, whereupon teratogenic deformity and death
may occur. Adult fish can survive and appear healthy despite the fact
that massive reproductive failure is occurring (Lemly 1985; Coyle et
al. 1993). Consequently, fish populations can decline or even disappear over the course of a few years for no apparent reason. In Belews
Lake, fish populations disappeared over a 4-year period (1974-1977),
and by the time biologists documented changes in population struc-
48
FIGURE 3.6. One of the most common and outwardly visible teratogenic effects
of selenium in Belews Lake fish was dorso-ventral spinal deformities (kyphosis and lordosis), shown here in mosquitofish (Gambusia affinis).
Ecological Implications
Insidious Mode of Toxicity
Selenium poisoning in fish can be "invisible" because the primary point
of impact is the egg, which receives selenium from the female's diet
and stores it until hatching, whereupon teratogenic deformity and death
may occur. Adult fish can survive and appear healthy despite the fact
that massive reproductive failure is occurring (Lemly 1985; Coyle et
al. 1993). Consequently, fish populations can decline or even disappear over the course of a few years for no apparent reason. In Belews
Lake, fish populations disappeared over a 4-year period (1974-1977),
and by the time biologists documented changes in population struc-