ABSTRACT: An understanding of lifetime trophic changes and ontogenetic habitat shifts is essential to the preservation of marine fish species. We used carbon and nitrogen stable isotope values (δ¹³C and δ¹⁵N) recorded within the laminar structure of fish eye lenses, reflecting both diet and location over time, to compare the lifetime trends of 2 demersal mesopredators. Tilefish Lopholatilus chamaeleonticeps inhabit burrows on the outer continental shelf, which results in exceptional site fidelity. Red grouper Epinephelus morio are spawned on the middle to outer continental shelf, move to the inner shelf for the juvenile period, and return offshore upon sexual maturity. Both species inhabit the eastern Gulf of Mexico, a region with a distinctive offshore-inshore gradient in background δ¹³C values. Within individual tilefish (n = 36), sequences of δ¹³C values and δ¹⁵N values had strong, positive correlations with eye-lens diameter, and strong correlations between the 2 isotopes (mean Spearman r = 0.86), reflecting an increase in trophic position with growth and little lifetime movement. In red grouper (n = 30), δ¹⁵N values positively correlated with eye-lens diameter, but correlations between δ¹⁵N and δ¹³C were weak (mean Spearman r = 0.29), suggesting cross-shelf ontogenetic movements. Linear mixed model results indicated strong relationships between δ¹⁵N and δ¹³C values in tilefish eye lenses but no convergence in the red grouper model. Collectively, these results are consistent with previously established differences in the life histories of the 2 species, demonstrating the potential utility of eye-lens isotope records, particularly for investigating the life histories of lesser-known species.

中文翻译：

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来自墨西哥湾东北部的两条深海鱼类的终生运动的同位素表征

摘要：了解一生的营养变化和个体发育的栖息地变化对于保护海洋鱼类至关重要。我们使用碳和氮稳定同位素值（δ ¹³ C和δ ¹⁵ N）的鱼眼透镜的层状结构内记录的，这反映了饮食和位置随着时间的推移，要比较的2个底层mesopredators寿命的趋势。fish鱼栖息在外大陆架上的洞穴中，这导致了特殊的地点保真度。红石斑鱼石斑鱼杜夫在中间至外部大陆架上产卵，在幼年时期移至内部架，并在性成熟时返回近海。这两个物种栖息墨西哥海湾东部，与背景鲜明离岸近海梯度δ的区域^13个C值。内的各个方头鱼（N = 36），δ的序列¹³ C值和δ ¹⁵的N值有较强的，阳性与眼透镜直径的2个同位素之间（平均斯皮尔曼R = 0.86），反射的增加相关，以及很强的相关性营养位置，生长发育，几乎没有一生的运动。在红色石斑鱼（N = 30），δ ^15个之间δN个值与眼透镜直径正相关，但相关性¹⁵ N和δ ¹³C较弱（平均Spearman r = 0.29），表明跨架的个体发育运动。线性混合模型结果表明强大的关系δ之间¹⁵ N和δ ^13个在方头鱼眼透镜C值，但在红色斑模型不收敛。总的来说，这些结果与先前在这两个物种的生活史中建立的差异相一致，这表明了眼透镜同位素记录的潜在用途，尤其是在研究鲜为人知的物种的生活史上。