MARE - Marine and Environmental Sciences Centre, Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Av. Nossa Senhora do Cabo, 939, 2750-374, Cascais, Portugal; Divisão de Oceanografia Ambiental e Bioprospecção, IPMA - Instituto Português do Mar e da Atmosfera, Av. Brasília, 1449-006, Lisboa, Portugal; CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.
Divisão de Oceanografia Ambiental e Bioprospecção, IPMA - Instituto Português do Mar e da Atmosfera, Av. Brasília, 1449-006, Lisboa, Portugal.
Chemosphere. 2019 May;223:714-722. doi: 10.1016/j.chemosphere.2019.02.061. Epub 2019 Feb 12.
The effects of body size and season on the elemental composition of ocean sunfish Mola mola were assessed for the first time. A total of 57 by-caught juvenile specimens measuring between 31.8 and 120.3 cm were sampled in spring and autumn. Concentrations of trace elements (three essential - Co, Cu, Zn, and three non-essential - As, Cd, Pb) were determined in five body tissues [gills, gelatin (subcutaneous white gelatinous layer), liver, white muscle and red muscle]. Elemental composition of M. mola tissues was found to vary with both body size and season. When an effect of size was verified, the most common trend was a decrease in elemental levels with increasing fish size, most likely deriving from the fast growth rate of this fish (i.e. dilution effect) and the occurrence of an ontogenetic shift in dietary preferences. Differently, Zn levels increased with fish size in both gills and red muscle, potentially deriving from a greater physiological need in those tissues as fish grow. Seasonal differences in trace element levels were observed for approximately half of the studied cases (tissue/trace element) with greater elemental concentrations being mostly found in autumn. Such pattern was most obvious in liver tissue, presumably resulting from a greater dietary elemental uptake in the end of summer/autumn. A general absence of seasonal differences was observed in the gills, white muscle and red muscle. Interestingly, a trend of enhanced concentrations in spring was observed for gelatin, potentially deriving from past long-term differences in exposure to trace elements.
首次评估了体型和季节对翻车鱼（Mola mola）元素组成的影响。共采集了 57 个 31.8 厘米至 120.3 厘米之间的幼鱼，分别来自春季和秋季样本。在五个组织[鳃、明胶（皮下白色凝胶层）、肝脏、白肌和红肌]中测定了痕量元素（三种必需元素-Co、Cu、Zn 和三种非必需元素-As、Cd、Pb）的浓度。发现 M. mola 组织的元素组成随体型和季节而变化。当验证体型的影响时，最常见的趋势是元素水平随鱼体增大而降低，这很可能是由于这种鱼的快速生长速度（即稀释效应）和饮食偏好的发生了个体发育转变。不同的是，鳃和红肌中的 Zn 水平随鱼体大小而增加，这可能是由于随着鱼体生长，这些组织的生理需求更大。大约一半的研究案例（组织/痕量元素）观察到了痕量元素水平的季节性差异，秋季的元素浓度较高。这种模式在肝脏组织中最为明显，可能是由于夏季末/秋季的饮食中元素摄入增加所致。在鳃、白肌和红肌中普遍没有观察到季节性差异。有趣的是，明胶在春季的浓度呈增强趋势，这可能源于过去长期暴露于痕量元素的差异。
