Does brown trout (Salmo trutta L.)
larval development retardation caused by short-term exposure to low pH and
elevated aluminum concentration affect a second episode of toxicity?
M. Çalta-2002
Journal
of Applied Ichthyology, 18(3):
210-215
Abstract:
This study examines whether brown trout larval development
retardation caused by an early episode of low pH and elevated aluminum
toxicity affects the outcome of a later toxicity episode. Yolk-sac brown
trout, Salmo trutta L., were exposed to four different patterns of
low pH (4.5) and aluminum (12molL-1) episodes. A continuous
control (pH 5.6 and zero aluminum) was also provided.
Mortality in the control fish was 5.0%. The highest mortality (91.6%)
occurred in S. trutta subjected to two later episodes (treatment 2)
which were temporally very close together. Mortality declined (30%) as the
interval between the two episodes (treatment 3) was increased. The lowest
mortality (16.7%) occurred when the duration of the early episode was
doubled (treatment 4). Mortality in animals exposed to only a single episode
(treatment 1) at the late yolk-sac stage was rather higher (51.6%) when
compared with mortalities in animals exposed to double episodes, the first
of which being in the early yolk-sac stage (treatments 3 and 4). Mortality
was found to be very significant both among treatments (two-way analysis of
variance (anova),
df=4, F-value=3.01, P<0.05) and time periods (two-way anova,
df=5, F-value=4.84, P<0.01).
In all treatments, gross development, net uptake of minerals (except Mg) and
calcium deposition in the skeleton was impaired. The advantages and
disadvantages of larval development retardation in the early yolk-sac stage
is discussed.
(University of Firat, Faculty of Fisheries, 23119 Elazig, Turkey. E-mail:
mcalta@firat.edu.tr)