Borrell A, Aguilar A, Tornero V, Sequeira M, Fernandez G, Alis S
GRUMM, Dept. of Animal Biology, University of Barcelona, Barcelona 08071, Spain.
Environ Int. 2006 May;32(4):516-23. doi: 10.1016/j.envint.2005.12.001. Epub 2006 Jan 30.
Isotopic signatures and organochlorine pollutant loads of organisms reflect the characteristics of the waters in which they live and feed. To investigate population structure of bottlenose dolphins around the Iberian Peninsula we determined delta(13)C and delta(15)N in the skin and organochlorine (OC) levels in the blubber of stranded bottlenose dolphins inhabiting the Mediterranean (Catalonia, Valencia and Balearic Islands) and adjacent Atlantic waters (Huelva and Portugal). OC levels were high in all regions, reflecting the predatory habits of the species, its coastal distribution and the existence of intense agricultural and industrial activity throughout the region. PCB congeners showed a gradient from the relatively more chlorinated forms to those that are less so, and followed a northeast to northwest direction across the Iberian Peninsula. This suggests that PCB inputs are more recent in the temperate latitudes of the eastern Atlantic Ocean than in the western Mediterranean Sea. Comparatively, OC ratios and isotopic signatures proved to be more efficient ways of discriminating groups than did raw OC concentrations. Significant differences in delta(13)C and in PCB congener profiles indicate that dolphins from the Atlantic and the Mediterranean do not intermingle. In addition, the two Atlantic groups differed in delta(15)N signature, tDDT concentration, DDT/PCB ratio and the PCB congener profile, which also suggests some degree of isolation between them. In the Mediterranean, dolphins from Catalonia and Valencia were indistinguishable, suggesting a common distribution area. However, dolphins from the Balearic Islands differed from those of the Peninsula in their DDT/PCB ratio and from all the other sample groups in their PCB congener profiles, which supports the hypothesis that the deep waters between the Islands and the Peninsula represent an effective barrier for the species.
生物体的同位素特征和有机氯污染物负荷反映了它们生存和觅食水域的特征。为了调查伊比利亚半岛周围宽吻海豚的种群结构，我们测定了搁浅于地中海（加泰罗尼亚、瓦伦西亚和巴利阿里群岛）及邻近大西洋水域（韦尔瓦和葡萄牙）的宽吻海豚皮肤中的δ(13)C和δ(15)N以及鲸脂中的有机氯（OC）水平。所有区域的OC水平都很高，这反映了该物种的捕食习性、其沿海分布以及整个区域存在的密集农业和工业活动。多氯联苯同系物呈现出从氯含量相对较高的形态到较低形态的梯度变化，并在伊比利亚半岛上呈东北向西北的方向分布。这表明，与西地中海相比，多氯联苯在东大西洋温带纬度地区的输入时间更近。相比之下，OC比率和同位素特征被证明是比原始OC浓度更有效的区分种群的方法。δ(13)C和多氯联苯同系物谱的显著差异表明，来自大西洋和地中海的海豚不会相互混合。此外，两个大西洋种群在δ(15)N特征、总滴滴涕浓度、滴滴涕/多氯联苯比率和多氯联苯同系物谱方面也存在差异，这也表明它们之间存在一定程度的隔离。在地中海地区，来自加泰罗尼亚和瓦伦西亚的海豚无法区分，这表明它们有共同的分布区域。然而，巴利阿里群岛的海豚在滴滴涕/多氯联苯比率方面与半岛的海豚不同，在多氯联苯同系物谱方面与所有其他样本组都不同，这支持了以下假设：群岛和半岛之间的深水区域对该物种来说是一个有效的屏障。
