Otolith microstructure of brown sole Pseudopleuronectes herzensteini: validation of daily ring formation and the occurrence of microstructure denoting metamorphosis

Abstract

Brown sole Pseudopleuronectes herzensteini larvae and juveniles were reared to validate daily otolith ring formation. At 15°C, a check (a distinct ring) formed on the sagittae and lapilli at 6 days after hatching, and clear increments regularly formed outside the check. For both otoliths, the relationship between the number of days after hatching and number of increments was linear, and the slope of the line was approximately 1; therefore, daily formation was validated. At 12°C, the check formed on the lapillus 8 days after hatching. Accessory primordia (AP) began forming on the sagittae of metamorphosing larvae, and the shape of the sagittae became complicated. AP were not formed on the lapillus; concentric rings were formed throughout larval and juvenile stages. Wide and obscure increments formed on the lapilli during metamorphosis (metamorphosing zone, MZ). Based on MZ, concentric rings that have formed on the lapilli of juveniles can be separated into larval and juvenile rings. The morphs of large juveniles' lapilli were bilaterally asymmetric, and the blind-side lapilli were most suitable for otolith microstructure analysis. This study provides fundamental information for otolith microstructure analysis in wild brown sole.

Common otolith microstructure related to key early life‐history events in flatfishes identified in the larvae and juveniles of cresthead flounder Pseudopleuronectes schrenki

“…It is suggested that when otolith microstructure is analysed in juvenile lapilli, blind‐side lapilli are suitable for this analysis because it is possible to measure the width of otolith rings along a single axis throughout the larval and juvenile stages, at least, for specimens <51·6 mm L S . A similar change in the shape of lapilli was reported for P. herzensteini , P. yokohamae and R. tapirina juveniles (Sogard, ; Joh et al , , ). Hence, bilateral asymmetry in juvenile lapilli is probably a common feature in flatfish species.…”

“…The AP were present on the outer edge of the sagittae of metamorphosing larvae and juveniles. The formation of AP has been reported in many flatfish species (Sogard, ; Mordin et al , ; Joh et al , , ) and the formation of AP in sagittae may be a common feature in flatfishes. Until the formation of AP, the rings form concentrically from the central core of the sagittae.…”

“…The lapilli of wild large juveniles (range: 26·5–51·6 mm) did not have AP, and the rings formed concentrically were similar to those of reared specimens. In flatfishes, there are many reports showing that no AP are formed on lapilli (Sogard, ; May & Jenkins, , Amara et al , ; Joh et al , , ). Therefore, the absence of AP on lapilli may be a common character of otolith microstructure in flatfishes.…”

A novel length back-calculation approach accounting for ontogenetic changes in the fish length – otolith size relationship during the early life of sprat (Sprattus sprattus)

“…Such a change between life stages may cause short-term stagnation of length growth, because other adaptions to new lifestyle requirements (e.g., spindle shape, scales) were favoured over size increase. Beside clupeids, time-varying reduced growth during ontogeny can also be observed at the settlement of reef fishes (Wilson and McCormick 1997) and metamorphosis of flatfishes (e.g., Joh et al 2011). A reduction in length growth that is accompanied with a change in the relationship of fish and otolith length leads to complications in back-calculations of length like in Baltic sprat.…”

Pre-settlement processes of northern rock sole (Lepidopsetta polyxystra) in relation to interannual variability in the Gulf of Alaska

“…Therefore, larval growth increments could not be assigned to specific dates and instead, analyses were based on temperatures in fixed temporal windows across years. Some researchers (Sogard, 1991;May and Jenkins, 1992;Joh et al, 2011) have relied solely on flatfish lapilli due to the presence of clearer daily increments than observed in sagittae. In NRS, daily increments were consistently clearer in lapilli although there was no evidence of a metamorphosis check or zone, which was a primary focus of our study.…”