Validation of daily sagittal increments in the golden-spotted rabbitfishSiganus guttatus(Bloch) using known-age larvae and juveniles

Abstract

The study presents a first report on the validation of otolith increment in the golden-spotted rabbitfish Siganus guttatus. The formation of daily sagittal growth increments in S. guttatus was validated using hatchery-reared larvae and juveniles collected from day of hatching to day 35. Mean increments were 5.6, 13.1, 24.5 and 34.8 for the 7, 15, 25 and 35 day-old fish, respectively. The results demonstrated that sagittal increments were formed daily and thus can be used to determine the age in days of the species.

Validation of daily increment deposition and early growth of mud carp Cirrhinus molitorella

“…Before estimating age and hatching date of wild larvae and juveniles, however, increment deposition rate and the timing of the first increment formation should be validated and determined (Stevenson & Campana, ). The analysis of the otoliths from fishes reared from hatching is considered the most reliable method to determine the timing of the formation of the first increment and to validate daily increment formation (Campana, ; Song et al ., ; Soliman et al ., ). Formation of the first daily increment can occur at hatching, the onset of feeding, or yolk‐sac absorption (Song et al ., ; Green et al ., ; Joh et al ., ).…”

Early life-history of the spiny siganid Siganus spinus (Linnaeus 1758) inferred from otolith microstructure

“…Microstructure of the spiny siganid otolith consisted of a well‐defined core, next to it a hatch ring, three feeding rings and a progression of rings. A hatch ring and series of growth rings were also observed in S. guttatus sagittae (Soliman et al., 2009). This information, together with the significant fish length – otolith size relation obtained from the regression analyses and the assumed daily periodicity of otolith formation validated in S. guttatus (Soliman et al., 2009), establish the utility of otolith microstructure for age determination in spiny siganid (Campana and Neilson, 1985; Jones, 1986) and consequently for their use in understanding its early life‐history (Campana, 1989, 1992, 2001).…”

“…Four increments rather than ten were used prior to and after the increment width at settlement because the oldest juveniles were 25 days old or only a few days past their settlement. Daily periodic otolith ring formation was assumed in the species based on the validation study for S. guttatus (Soliman et al., 2009).…”

“…The skipjack tuna were 1.8-2.3 kg each in total fresh weight. After measuring the standard length (SL, mm) of each juvenile, the sagittae were extracted and prepared according to Soliman et al (2009) for S. guttatus juveniles. Briefly, the sagittae were cleaned and embedded in resin cast in a silicone mold.…”

Growth and mortality of larval Myctophum affine (Myctophidae, Teleostei)

“…If increment counts differed by >10%, the sagitta was discarded ( n = 9, 10%). Growth increments were interpreted as daily increments since they have been validated for many teleosts (Albuquerque et al ., ; Soliman et al ., ; Joh et al ., ), including myctophid species (Gartner, ; Hayashi et al ., 2001 a , b ; Moku et al ., , ).…”