Trasviña-Carrillo L D, Hernández-Herrera A, Torres-Rojas Y E, Galván-Magaña F, Sánchez-González A, Aguíñiga-García S
Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, Av. IPN s/n, C.P. 23096, La Paz, Baja California Sur, Mexico.
Instituto de Ecología, Pesquerías y Oceanografía del Golfo de México, Universidad Autónoma de Campeche (EPOMEX-UAC), Campus 6. Av. Héroe de Nacozari #480, C.P. 24029, Campeche, Camp, Mexico.
Rapid Commun Mass Spectrom. 2018 Aug 15;32(15):1225-1236. doi: 10.1002/rcm.8147.
The jumbo squid Dosidicus gigas is a fishery resource of considerable economic and ecological importance in the Mexican Pacific. Studies on its habitat preferences are needed to understand recent fluctuations in the abundance and availability of the species. Stable isotope analysis allows us to infer ecological aspects such as spatial distribution and trophic preferences.
We used an isotope ratio mass spectrometer, automated for carbonate analysis, and coupled to an elemental analyzer, to determine the isotopic composition of statoliths (δ O and δ C values) and beaks (δ C and δ N values) from 219 individuals caught over two fishing seasons (2007 and 2009) off the coast of Santa Rosalía, in the central Gulf of California. We used these isotopic ratios to assess variation in spatial and trophic preferences by sex, size, and fishing season.
In the 2009 group, we observed significant differences in statolith δ C values and beak δ C and δ N values between males and females. Between size groups, we observed significant differences in statolith δ O and δ C values in 2007 and in beak δ C and δ N values during both seasons. Both seasons were characterized by high overlap in δ O and δ C values between sexes and in 2009 between size groups. We observed low trophic overlap between sexes in 2009 and between size groups during both seasons.
The isotopic ratios from statoliths and beaks indicate that D. gigas has changed its spatial and trophic preferences, a shift that is probably related to changes in the species' diet. This intraspecific variation in preferences could be related to characteristics such as size, which may influence squid distribution preferences.
巨型鱿鱼茎柔鱼是墨西哥太平洋海域具有重要经济和生态意义的渔业资源。需要对其栖息地偏好进行研究，以了解该物种近期在丰度和可捕量方面的波动情况。稳定同位素分析使我们能够推断出诸如空间分布和营养偏好等生态方面的情况。
我们使用了一台用于碳酸盐分析的自动化同位素比率质谱仪，并将其与元素分析仪联用，以测定从加利福尼亚湾中部圣罗萨利亚海岸两个捕鱼季节（2007年和2009年）捕获的219只个体的耳石（δO和δC值）和喙（δC和δN值）的同位素组成。我们利用这些同位素比率来评估性别、大小和捕鱼季节在空间和营养偏好方面的差异。
在2009年的样本组中，我们观察到雄性和雌性在耳石δC值以及喙δC和δN值上存在显著差异。在不同大小组之间，我们观察到2007年耳石δO和δC值以及两个季节中喙δC和δN值存在显著差异。两个季节的特点都是性别之间以及2009年不同大小组之间在δO和δC值上有高度重叠。我们观察到2009年性别之间以及两个季节不同大小组之间营养重叠程度较低。
耳石和喙的同位素比率表明，茎柔鱼已经改变了其空间和营养偏好，这种变化可能与该物种饮食的改变有关。这种偏好的种内差异可能与大小等特征有关，大小可能会影响鱿鱼的分布偏好。
