ISSN:
1573-2932
Keywords:
low pH
;
acid exposure
;
salmonid fish
;
gametogenesis
;
embryo development
;
sex steroid
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract Mature male and female rainbow trout were treated with low pH (Av. 4.5) sulfuric acid water for 1 or 2 weeks. Percentage of eyed embryos in eggs from control, 1-week-treated and 2-week-treated females were 100%, 80% and 0%, respectively. Low pH exposure of male trout induced 11% deformation in embryos fertilized with their sperm. In order to clarify the physiological mechanism of the effects of low pH exposure, sex hormone levels were compared. In female fish, plasma sex hormones levels showed no difference among the groups, but egg contents of 17α20β-dihydroxy-4-pregnen-3-one, which induces oocyte maturation, were significantly lower in low pH exposed groups. Acidified male fish showed higher plasma levels of the spermiation inducing hormone, 11-ketotestosterone. Effects on eggs were manifested under pH lower than 5. Under continual rearing of land-locked sockeye salmon in acid water, the effects on the oocyte were observed in those adult females which were exposed to acidic condition for more than 1 week before the timing of ovulation. These results suggest that low pH affects oocyte maturational events occurring just 1 week before ovulation, and that acid stress affects the endocrinological mechanisms of final maturation in fish gametocytes. Thus, acidification of the aquatic environment may reduce the reproductive activity of fish at rather low acidity levels.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00476850
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