Geochemical data on otoliths of chaetodon speculum from New Caledonia

coral reefs are one of the most diverse ecosystems on earth. they are currently exposed to increasing levels of anthropogenic perturbations. several recent reviews point to the lack of good indicators for these perturbations especially to monitor their effects on fish populations or fish assemblages. the sw lagoon of new caledonia is an ideal location to test indicator species in this context as contrasting sites are present within a small geographical range. this study analysed fish from four sites, one with heavy industrial pollution, another dominated by domestic waste, a third with historic mining activities, and the fourth as a control. the butterfly fish, chaetodon speculum, was chosen to determine c. speculum’s potential as an indicator species due to its link to coral, its sedentary behaviour and its wide geographical distribution. the size distribution, growth rate, age distribution and whole otolith composition were analysed at each site. age and mean growth rate were analysed from daily increments of the otoliths. the concentrations of eight elements (li, mg, co, cu, rb, sr, and ba) were measured by icp-ms in the otoliths.the sites under anthropogenic impact were distinct from the control site by fish size frequencies, age distributions, and the chemical content of their otoliths. the chemical elements mg, co, cu, and rb showed differences amongst sites. fish belonging to the sites furthest from noume´a could be discriminated in nearly 80% of samples or 60% of the cases when otolith weight or fish age respectively were taken into account. ni concentrations of the otoliths were also higher in the bays where water concentrations of this element were known to be higher, but these differences were no longer significant once corrected for otolith weight.

珊瑚礁作为地球上最具多样性的生态系统之一，目前正面临着日益加剧的人为干扰。数篇近期综述指出，对于监测这些干扰对鱼类种群或鱼群组合的影响，缺乏良好的指示指标。新喀里多尼亚的Sw潟湖是检验此背景下指示物种的理想地点，因为在该小地理范围内存在对比鲜明的地点。本研究分析了来自四个地点的鱼类，其中一地为重度工业污染，另一地为家庭废弃物主导，第三地为历史采矿活动，第四地为对照。由于蝴蝶鱼（Chaetodon speculum）与珊瑚的联系、其定居行为以及其广泛的地理分布，因此选择了这种蝴蝶鱼作为确定其作为指示物种潜力的对象。在每个地点，对蝴蝶鱼的大小分布、生长速率、年龄分布和整个耳石组成进行了分析。年龄和平均生长速率是通过耳石每日增长量进行分析的。八个元素（Li、Mg、Co、Cu、Rb、Sr和Ba）的浓度是通过ICP-MS在耳石中测量的。受人为影响的地域与对照地点在鱼类大小频率、年龄分布和耳石化学成分上存在显著差异。元素Mg、Co、Cu和Rb在不同地点间显示出差异。与努美阿较远地点的鱼类在近80%的样本中或60%的情况下，当考虑耳石重量或鱼龄时，可以被区分开来。耳石中的Ni浓度也较高，因为已知这些海湾中该元素的水浓度较高，但一旦对耳石重量进行校正，这些差异便不再显著。