Correlation between otolith structure and early growth of Gymnocypris przewalskii larvae and juveniles
WANG Yang，FANG Di’an，KUANG Zhen，TAN Longfei，LIANG Yidong，LUO Hui，QI Hongfang，XU Dongpo*
1.Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization，Ministry of Agriculture and Rural Affairs，Freshwater Fisheries Research Center，Chinese Academy of Fishery Sciences，Wuxi 214081，China；2.Laboratory of Breeding and Conservation of Naked Carp in Qinghai Lake，The Rescue and Rehabilitation Center of Naked Carp in Qinghai Lake，Xining 810016，China；3.College of Fisheries and Life Science，Shanghai Ocean University，Shanghai 201306，China
Abstract: In order to clarify relationship between structure of otolith and early growth characteristics in larval and juvenile Gymnocyprisprzewalskii, the microstructural characteristics was observed and the appearance time of the first rings and deposition pattern of the otolith rings were comparatively identified in larval otolith of cultured and wild G.przewalskii from artificial breeding and collected from Shaliu River (37°18′50.93″ N, 100°08′6.86″ E) and Quanji River (37°14′7.10″ N, 99°53′3.78″ E), the migratory spawning tributaries of Qinghai Lake. The otolith deposition was observed in the larvae and juveniles exposed to 10, 15, and 20 ℃ in temperature marking test and the correlations between the otolith daily age, width of otolith marking rings and daily age were fitted. It was found that the deposition of otolith diurnal cycle is daily. The larval fish daily age was calculated by the otolith rings number plus 1 (N+1). The daily age and sampling date revealed that the larvae and juveniles collected in Shaliu River in 2020 were incubated from June 5th to August 14th, peak in mid-July and early August. The larvae and juveniles in Quanji River were incubated from June 27th to August 3rd, the peak period in the mid-July. The results above were basically consistent with the fish larvae appearance time found in field investigation. The total length of larval and juvenile had significant linear, correlated with daily age, the otoliths length had significant linear correlated with fish total length with the maximal correlation coefficient in the artificially cultivated larvae and juveniles at water temperature of 15 ℃. The fitted equation was shown to be LT=0.167 2t+10.377(R2=0.689 0, P<0.001). The otolith growth of the larvae and juvenile was greatly affected by the environmental factors, and the variation of otolith deposition was closely related to the growth and development of larvae and juveniles.
2024, Vol. 39 
