BACKGROUND We investigated the feeding ecology and habitat use of 32 harbour porpoises by-caught in 4 localities along the Scandinavian coast from the North Sea to the Barents Sea using time-integrative markers: stable isotopes (delta13C, delta15N) and trace elements (Zn, Cu, Fe, Se, total Hg and Cd), in relation to habitat characteristics (bathymetry) and geographic position (latitude). RESULTS Among the trace elements analysed, only Cd, with an oceanic specific food origin, was found to be useful as an ecological tracer. All other trace elements studied were not useful, most likely because of physiological regulation and/or few specific sources in the food web. The delta13C, delta15N signatures and Cd levels were highly correlated with each other, as well as with local bathymetry and geographic position (latitude). Variation in the isotopic ratios indicated a shift in harbour porpoise's feeding habits from pelagic prey species in deep northern waters to more coastal and/or demersal prey in the relatively shallow North Sea and Skagerrak waters. This result is consistent with stomach content analyses found in the literature. This shift was associated with a northward Cd-enrichment which provides further support to the Cd 'anomaly' previously reported in polar waters and suggests that porpoises in deep northern waters include Cd-contaminated prey in their diet, such as oceanic cephalopods. CONCLUSION As stable isotopes and Cd provide information in the medium and the long term respectively, the spatial variation found, shows that harbour porpoises experience different ecological regimes during the year along the Scandinavian coasts, adapting their feeding habits to local oceanographic conditions, without performing extensive migration.

中文翻译：

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从痕量元素和稳定同位素推断出的斯堪的纳维亚水域海豚海豚的长期摄食生态学和栖息地使用情况。

背景技术我们使用时间整合标记：稳定同位素（δ13C，δ15N）和微量元素（锌，锌，锌，铜，铁，硒，总汞和镉），与栖息地特征（测深法）和地理位置（纬度）有关。结果在分析的痕量元素中，仅发现具有海洋特定食物来源的Cd可用作生态示踪剂。研究的所有其他微量元素均无用，最有可能是由于生理调节和/或食物网中很少的特定来源。delta13C，delta15N签名和Cd水平彼此高度相关，并且与局部测深法和地理位置（纬度）高度相关。同位素比率的变化表明，海豚的摄食习性从北部深水域的上层捕食物种转变为相对浅的北海和Skagerrak水域的更多沿海和/或海底猎物。该结果与文献中发现的胃内容物分析一致。这种变化与向北的镉富集有关，这为先前在极地水域中报告的镉“异常”提供了进一步的支持，并暗示北部深水区的海豚在其饮食中包括受镉污染的猎物，例如海洋头足类。结论由于稳定的同位素和Cd分别在中期和长期提供信息，因此发现的空间变化表明，在斯堪的纳维亚沿海，港口海豚在一年中经历了不同的生态系统，