Inter-individual variation in trophic history of Dosidicus gigas, as indicated by stable isotopes in eye lenses

• Published in: Aquaculture and fisheries 2019-11, Vol.4 (6), p.261-267
• Main Authors: Xu, Wei, Chen, Xinjun, Liu, Bilin, Chen, Yong, Huan, Mengyao, Liu, Na, Lin, Jingyuan
• Format: Article
• Language: English
• Subjects: Dosidicus gigas; Eye lenses; Stable isotope; Trophic habitat
• ISSN: 2468-550X; 2468-550X
• DOI: 10.1016/j.aaf.2019.05.001

Isotopic signatures have been extensively used to reconstruct marine organism trophic habitat over their lifetime. In this study, sequential stable isotopic values of δ13C and δ15N in eye lenses were measured to investigate the trophic history of Dosidicus gigas during ontogeny. A total of 281 segments from 33 lenses were examined with δ13C ranging from −20.17‰ to −16.11‰ and δ15N ranging from 5.15‰ to 18.74‰. Sequential increasing but variable δ13C and δ15N values in eye lenses indicated that the prey used in the model had a wide range of values, it became able to consume prey from higher trophic levels, perhaps to maximize feeding success. High inter-individual differences in the range and considerable inter-individual variation in the trend of the isotopic values of the sequential segments from the nuclear to the periphery were considered to be the result of the effects of food and the best feeding strategy. These inter-individual isotopic differences in the life history of D. gigas confirmed the high degree of plasticity of feeding for this squid and its high potential to adapt to environmental change. Inter-individual differences of δ15N values in the growth of D. gigas were more likely to be caused by differences in the baseline values of isotopes. According to the population discrimination model of δ15N value changes during ontogeny, the D. gigas off Peru fit the model of “generalist population-generalist individuals”.