Predation on pirarucu larvae by opportunistic fish species

ABSTRACT One of the constraints in pirarucu, Arapaima gigas farming is the reproduction in captivity, due to inconsistent number of spawning events per reproductive cycle, thus, unreliable availability of juvenile fish. This is a first-hand report on predation of pirarucu larvae by opportunistic fish species in a breeding pond. Fish samples were collected for stomach content analysis from a pirarucu-breeding pond with reported predation on the larvae. We obtained 61 fish of different species (Tetragonopterus sp., Astyanax bimaculatus, Moenkhausia intermedia, Hoplias malabaricus, and Apistogramma sp.). Tetragonopterus sp. stomachs had the highest frequency of occurrence of pirarucu larvae (83.3%), followed by A. bimaculatus (7.4%). The relationship between the feeding behaviour of these species and their predation upon pirarucu offspring is discussed.摘要 巨骨舌鱼（Arapaima gigas）养殖的主要制约因素之一为人工圈养繁殖：其每个生殖周期的产卵事件数量不稳定，进而导致幼鱼供应难以保障。本研究首次报道了繁殖池塘内机会性鱼类捕食巨骨舌鱼幼鱼的情况。研究人员从存在幼鱼捕食记录的巨骨舌鱼繁殖池塘中采集鱼类样本以开展胃容物分析。本次共采集到61尾不同物种的鱼类，包括四棱鲃属未定种（Tetragonopterus sp.）、双斑直线脂鲤（Astyanax bimaculatus）、间梅肯脂鲤（Moenkhausia intermedia）、马拉巴利虎脂鲤（Hoplias malabaricus）以及隐带丽鱼属未定种（Apistogramma sp.）。其中四棱鲃属未定种（Tetragonopterus sp.）的胃容物中检出巨骨舌鱼幼鱼的出现频率最高，达83.3%，其次为双斑直线脂鲤（7.4%）。本文还探讨了上述鱼类的摄食行为与其捕食巨骨舌鱼后代之间的关联。