Ontogenetic vertical migration of deep sea demersal fishes revealed by otolith microstructure, δ13C and δ18O stable isotope composition
Date Issued
2015
Date
2015
Author(s)
Sui, Tsung-Da
Abstract
Reconstructing ontogentic vertical migration (OVM) of deep sea demersal fishes is useful to understand their life history strategies. Nevertheless, information of the depth distribution at each life history stages of deep-sea fish is still scarce based on limited catching records. Otolith microstructure and stable isotope analyses are effective tools to study OVM of fish. Fish samples were collected by R/V Ocean Researcher I, from DaiShi harbor or by a fisherman in ChangBin. In this study, we analyzed the otolith microstructure and isotopic composition for 10 fish species belonged to 7 families. We compared our data to published data in order to provide a comprehensive understanding of OVM among species. The results suggest otolith δ13C and δ18O reflect metabolism and environmental temperature respectively, which can be used to reconstruct individual OVM. The residing depth distribution of the fish at each life history stages can be deduced from otolith δ18O. Lutjanidae, Uranoscopidae, Chlorophthalmidae and Peristediidae have OVM similar to other species analyzed in previous studies that showed a gradual migration to deeper water. Jellynose fish (Ateleopodidae), blackthroat seaperch (Doederleinia berycoides), and Elassodiscus obscurus showed unique OVM. Juveniles of jellynose fish migrated from ocean surface down to depths (600-1300 m) at around 63 days, then the fish rose quickly to around 200 m. D. berycoides showed up and down OVM among seasons and years. E. obscurus inhabited at 1500 m depth during early life stage then migrated to around 600 m depth. The relationship between distance of OVM and adult residence depth varied among species with different reproduction modes. Positive correlations were found for viviparous species and that produce pelagic eggs. However, no correlation was found in Alepocephalidae and E. obscurus that lay larger eggs. Some exceptions were found in jellynose fish and Hoplostethus melanopus. The formal had a long distance of OVM but depth of adult’s habitat is shallow and the latter did not showed OVM. This research revealed diversified OVM for deep sea fish, suggesting different strategies were evolved to cope with the harsh environments in the deep seas.
Subjects
deep-sea demersal fish
otolith
stable isotope
ontogenetic vertical migration
life history
Type
thesis
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