利用耳石矢平面轮纹宽度度量南极鱼类的生长:以南极电灯鱼为例

USING RING WIDTH ON SAGITTAL PLANE OF OTOLITH TO REVEAL THE GROWTH OF ANTARCTICA FISH SPECIES: A CASE STUDY OF ELECTRONA ANTARCTICA

耳石矢平面轮纹宽度可用于指示鱼类的生长特性,这在其他种类中已得到应用,但在南极鱼类中尚无此类研究。为了探究耳石矢平面轮纹宽度在南极鱼类的适用性,本研究以南极电灯鱼(Electrona antarctica)为例,通过2016年1—2月于南凯尔盖朗海域3个站点采集的50尾南极电灯鱼,在对其进行年龄鉴定后,利用赤池信息准则(AIC)选取最适合的测量方向,并对耳石矢平面明暗交替的轮纹进行了宽度测量。在此基础上,本研究分别拟合耳石轮纹中的不透明带、透明带及不透明带和透明带所构成的完整年轮宽度与年龄、体长及体重之间的函数关系,并对轮纹的累加宽度和年龄、体长及体重进行了拟合。结果表明,在轮纹宽度与年龄的关系中, 3龄为轮纹宽度变化的转折点, 3龄之前南极电灯鱼快速生长,之后生长速度有所下降。在轮纹宽度分别与体长、体重的关系中,体长为70 mm、体重为8 g时为轮纹宽度变化的转折点。当体长不足70mm或体重不超过8g时,增长较快,且冬、夏季均有所增长,之后增长减缓,冬季增长十分微小,甚至停止增长。本研究探讨了耳石轮纹宽度随年龄、体长及体重变化的变化趋势,从而得出南极电灯鱼各生活史阶段生长在年龄、体长及体重方面的变化规律。本研究首次针对南极鱼类耳石的轮纹宽度与其生长之间的关系进行了分析,丰富了鱼类耳石研究的范畴。

Ring width in the sagittal plane of otoliths can be considered as an indicator of fish growth,though this application has not yet been applied to any Antarctic species.Therefore,a case study was made using 50 Antarctic lanternfish Electrona antarctica collected from three locations at the Southern Kerguelen Plateau,Indian sector,in January–February 2016,to investigate the species’ growth.Akaike’s information criterion was used to select the direction of measurement after aging the fish,and the ring width in the sagittal plane was measured in the selected direction.Relationships between opaque rings,translucent rings,and annual rings in the otoliths and the age,standard length(SL),and body weight of fish were fitted with different functions.Relationships between accumulative ring width of the otolith sections and the age,SL,and body weight of fish were also fitted.The results indicated significant difference at the period of 3 years old.E.antarctic rapid growth during the first three years,and thereafter the growth rate decreased.Change in ring width was observed when fish attained sizes of 70 mm SL or 8 g.E.antarctica grew rapidly at smaller sizes,and ring width in the otoliths increased during both winter and summer.This study demonstrated variation in ring width in otoliths with age,SL,and body weight,and thus with life-history stage.To our knowledge,this is the first work to analyze ring width in otoliths in relation to the growth of an Antarctic fish,thereby extending the field of fish otolith research.