Validation of daily increment formation in otoliths for Gymnocypris selincuoensis in the Tibetan Plateau, China

Abstract

Daily increment validation in fish otolith is fundamental to studies on fish otolith microstructure, age determination and life history traits, and thus is critical for species conservation and fishery management. However, it has never been done for Schizothoracine fish, which is the dominant component of fish fauna in the Tibetan Plateau. This study validated the daily increment formation of Gymnocypris selincuoensis, as a representative of Schizothoracine fish, by monitoring the growth of hatchery-reared larvae group and wild-caught post-yolk-sac larvae group under controlled experiments. The results from monitoring the hatchery-reared larvae group showed that sagittae and lapilli were found in yolk-sac larvae, and formed 5–7 days before hatching, but asterisci were not found until 11 days post-hatching. The first increment in sagittae and lapilli was formed in the first day after hatching. The daily periodicity of increment formation was examined and confirmed in sagittae and lapilli of both larvae groups. However, sagittae were better for age determination than lapilli for larvae at earlier days. For larval G. selincuoensis older than 50 days, lapilli were the only otolith pair suitable for larvae daily age determination. This study validated the daily increment formation in Schizothoracine fish for the first time has primary implications to other fishes from this subfamily.

Growth variation of Schizothorax dulongensis Huang, 1985 along altitudinal gradients: implications for the Tibetan Plateau fishes under climate change

“…Compared with populations inhabiting the lower‐altitude reaches, the higher altitude populations experienced lower water temperatures and shorter growing seasons. Such results are consistent with previous studies on other Schizothoracinae fish (Ding et al., ; Tao et al., ). Rearing experiments also found that temperature could enhance the growth of Schizothorax (Racoma) kozlovi as long as the temperature was below 32°C (He et al., ).…”

“…Schizothoracinae fish (Cyprinidae, Cypriniformes) are the predominant vertebrate group in aquatic ecosystems of the Tibetan Plateau and adjacent areas. Our previous study found that the Schizothoracinae fish can be powerful in the detection of environmental or climate changes (Tao et al, 2015). However, few studies related to growth variation have been done in this group (He et al, 2014).…”

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

“…Hence, age of wild C. molitorella can be estimated from the number of increments in lapilli. Daily increments in otoliths have been verified for other Cypriniformes (Green et al ., ; Yan et al ., ; Ding et al ., ).…”

Otolith shape analysis and daily increment validation during ontogeny of larval and juvenile European chub Squalius cephalus

“…Increment counts also confirmed daily increments deposition in otolith of S. cephalus . These results are consistent with previous findings on larval and juvenile cyprinids (Morioka & Matsumoto, ; Ding et al ., ; Yan et al ., ).…”