水体钙离子质量浓度对褐牙鲆幼鱼鱼体和耳石元素成分的影响

在盐度30和水温20 ℃条件下，分别配制钙离子ρ（Ca2＋）质量浓度为200 mg·L-1（A组）、400 mg·L-1（B组，对照）、800 mg·L-1（C组）、1 600 mg·L-1（D组）和3 000 mg·L-1（E组）的人工海水，研究了水体ρ（Ca2＋）对褐牙鲆（Paralichthys olivaceus）幼鱼鱼体和耳石元素成分的影响。经60 d养殖发现褐牙鲆鱼体中仅钙（Ca）、锌（Zn）和铜（Cu）质量分数差异不显著（P〉0.05）；鱼体中磷（P）、钠（Na）、镁（Mg）、锶（Sr）、铁（Fe）、锰（Mn）和镍（Ni）质量分数随水体ρ（Ca2＋）的增加而下降。不同ρ（Ca2＋）对褐牙鲆幼鱼耳石长、宽、长宽比和耳石质量影响显著（P〈0.05）。低浓度A组耳石长和耳石宽显著低于B组和C组，A组耳石长宽比（L/W）显著低于D组，A组的耳石质量显著低于B组和D组（P〈0.05）。其中w（Sr）随ρ（Ca2＋）的增加显著下降，锶/钙（Sr/Ca）比、镁/钙（Mg/Ca）比随ρ（Ca2＋）增加而下降。结果表明，水体ρ（Ca2＋）对褐牙鲆鱼体成分、耳石形成及组分产生明显影响，ρ（Ca2＋）能够影响鱼体和耳石元素的累积。

Effects of Ca2+ concentrations in seawater on element content of fish body and otolith of juvenile Paralichthys olivaceus

We investigated the effects of Ca2＋ concentrations on element content of fish body and otolith of juvenile Paralichthys olivaceus that were raised at 20℃ in artificial seawater for 60 more days. Five groups of seawater with Ca2＋ concentrations 200 mg？L-1 （group A）, 400 mg？L-1 （group B, control）, 800 mg？L-1 （group C）, 1 600 mg？L-1 （group D）, and 3 000 mg？L-1 （group E）, were used for raise. It was found that with the increase of Ca2＋ concentration, the contents of P, Na, Mg, Sr, Fe, Mn and Ni in fish body decreased, and that Ca2＋ concentrations significantly influenced the otolith length, width, L/W and weight. Specifically, otolith length and width of juvenile P.olivaceus group A were significantly lower than that of group B and C; L/W was significantly lower than that of group D; and otolith weight was significantly lower than that of group B and D. Sr content of otolith, significantly, and the ratio of Sr/Ca and Mg/Ca also decreased with increasing concentration of Ca2＋. The results indicate that Ca2＋ concentrations affect juvenile P.olivaceus significantly in terms of its body and otolith element content formation, composition and accumulation.