Vertical habitat shift of viviparous and oviparous deep‐sea cusk eels revealed by otolith microstructure and stable‐isotope composition

Abstract

Otolith stable-oxygen-isotope composition and microstructure were analysed in order to investigate the vertical habitat shift of deep-sea cusk eels (Ophidiiformes). Otolith δ O profiles suggested that both viviparous blind cusk eels and oviparous cusk eels experienced a pelagic larval stage and then settled to the deep-sea floor over a vertical distance that ranged among individuals from 200 to >1000 m. This result shows that the larvae of viviparous Barathronus maculatus undertake an ontogenetic vertical migration after a period of larval drift that may facilitate their wide distribution on the sea floor.

Up‐and‐down shift in residence depth of slickheads (Alepocephalidae) revealed by otolith stable oxygen isotopic composition

“…δ 18 O w (VSMOW scale) was converted to the VPDB scale via the equation: δ 18 O wVPDB = 0·99978 δ 18 O wVSMOW − 0·22, which was explained by Chang et al . (). Accordingly, the residence depth of the fishes can be estimated from the measured δ 18 O oto value based on the predicted δ 18 O oto profile across depths (Fig.…”

“…18 O oto values were reported in standard notation as the following, with comparison to standard Vienna Pee Dee Belemnite (VPDB) through calibration against the NBS19 standard: (Fig. 3) based on the modified equation from Kim & O'Neil (1997) 18 O wVPDB = 0⋅99978 18 O wVSMOW − 0⋅22, which was explained by Chang et al (2015). Accordingly, the residence depth of the fishes can be estimated from the measured 18 O oto value based on the predicted 18 O oto profile across depths (Fig.…”