Food web investigations using stable isotope analyses inform management strategies by quantitatively describing interactions among species. Fin tissue is a nonlethal alternative to white muscle tissue for obtaining stable isotope ratios of fish. However, the relationship between fin and muscle values must be evaluated before fin tissue can be substituted for muscle tissue. We examined the relationships between fin and muscle carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios in 15 species of North American freshwater fish using linear regression for multispecies models and species‐specific models, and compared the performance of our models against models developed for European and Australian freshwater fishes. Fin and muscle isotope ratios differed but covaried with good explanatory power ( = 0.74–0.99; = 0.45–0.99). Useful conversions of fin isotope values were provided by our species‐specific models (δ¹³C_error = 0.27‰; δ¹⁵N_error = 0.22‰), and to a lesser extent our multispecies models (δ¹³C_error = 0.51‰; δ¹⁵N_error = 0.35‰) and the European models (δ¹³C_error = 0.57‰; δ¹⁵N_error = 0.42‰). Models developed for Australian fishes gave less precise conversions when applied to North American freshwater species (δ¹³C_error = 0.78‰; δ¹⁵N_error = 0.82‰). We recommend using species‐specific conversion models when available, but in their absence, multispecies models may be adequate. Our study contributes to a growing literature seeking fin–muscle conversion models, which should serve to reduce the lethal take of individuals.

中文翻译：

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北美淡水鱼的非致死性鳍采样，用于使用稳定同位素进行食物网研究

使用稳定同位素分析进行​​的食物网调查通过定量描述物种之间的相互作用，为管理策略提供了依据。鳍状组织是白肌肉组织的一种非致命性替代品，可用于获得稳定的鱼类同位素比。但是，必须先评估鳍和肌肉值之间的关系，然后才能用鳍组织代替肌肉组织。我们检查了鳍和肌肉碳（δ之间的关系¹³ C）和氮（δ ¹⁵N）使用多物种模型和特定物种模型的线性回归对15种北美淡水鱼的同位素比率进行比较，并将我们的模型的性能与针对欧洲和澳大利亚淡水鱼开发的模型进行比较。鳍和肌肉同位素比率不同，但具有良好的解释力（= 0.74–0.99；= 0.45–0.99）。鳍同位素值的有用的转化率我们的物种特异性模型提供（δ ¹³ C ^_误差 = 0.27‰;δ ¹⁵ Ñ_误差 = 0.22‰），并在较小程度上提供了多种类的模型（δ ¹³ C ^_误差 = 0.51‰;δ ¹⁵ N_误差 = 0.35‰）和欧洲模型（δ¹³ C_误差 = 0.57‰; δ ¹⁵ Ñ_误差 = 0.42‰）。当施加到北美淡水物种（δ澳大利亚鱼类开发的模型，得到不太精确的转换¹³ Ç_误差 ;δ= 0.78‰ ¹⁵ Ñ_误差 = 0.82‰）。我们建议使用特定物种的转化模型（如果可用），但是如果没有这些模型，则多物种模型可能就足够了。我们的研究为寻求鳍-肌肉转换模型的文献提供了帮助，该模型应有助于减少个体的致死性。