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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?
Author(s) -
Çalta M.
Publication year - 2002
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1046/j.1439-0426.2002.00350.x
Subject(s) - brown trout , salmo , biology , zoology , toxicity , yolk sac , yolk , analysis of variance , larva , trout , medicine , fish <actinopterygii> , fishery , ecology , embryo
Summary 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 (12 mol L −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.