Age and growth of Ceratoscopelus warmingii (Myctophidae) in the South China Sea based on sagittal otolith microstructure

Abstract

ABSTRACT Age and growth of a dominant lanternfish Ceratoscopelus warmingii in the South China Sea were investigated based on sagittal otolith microstructure of juvenile and adult specimens collected in June 2015. The length–weight (L-W) relationship for C. warmingii was Wf = 0.00000814 L 3.1170 (females) and Wm = 0.00001071 L 3.3043 (males), revealing both positive allometric growth and non-significant difference between the sexes. Three distinct zones of the otolith microstructure were depicted, a central zone (CZ), middle zone (MZ) and external zone (EZ). Age was estimated by summing the daily growth increments in otolith sections on the assumption of daily deposition. The von Bertalanffy models of females and males were fitted as Lf = 75.9 [1−exp{−0.0074 (t−14.1)}] and Lm = 65.0[1−exp{−0.0097 (t−7.6)}], respectively. The maximum growth rates estimated were 0.319 mm day−1 for females and 0.345 mm day−1 for males, and thereafter the growth rate decreased with age. The back-calculated hatching date of specimens collected was determined as from August of last year to March of next year with a peak in winter. Theoretical maximum growth of C. warmingii appeared to occur near the metamorphic period.