Ocean Sunfishes Information Storage Museum, Nara, Japan.
Auckland War Memorial Museum Tamaki Paenga Hira, Natural Sciences, The Domain, Auckland, New Zealand.
J Fish Biol. 2022 Jun;100(6):1345-1364. doi: 10.1111/jfb.15039. Epub 2022 Apr 20.
The world's heaviest extant bony fish has long been considered the ocean sunfish Mola mola (family Molidae). However, recent taxonomic research suggests the world record specimen (2300 kg) was actually a misidentified giant sunfish M. alexandrini. Moreover, the history of taxonomic confusion in the genus Mola, combined with anecdotal size information perpetuated in both media and literature, has resulted in uncertainty in regard to species identity and actual weights of very large Mola specimens. In this study, we searched for records of molid specimens with reported body mass over 2000 kg, with a focus on the north-west and south-west Pacific. For each specimen, we reviewed the species identification and assessed the reliability of the information, including if the specimen had actually been weighed. Of the 15 specimens uncovered, we identified one M. mola and 14 M. alexandrini, and found that only five had actually been weighed (one with the viscera removed). Furthermore, we collected length-weight data for verified M. alexandrini specimens from the literature and museum specimens, and established the first length-weight relationship for this species [body mass (kg) = 1.1 × 10 × total length (cm) (29-330 cm total length, n = 20)]. These findings are discussed in the context of other extant bony fish species, which allegedly also exceed 2000 kg in body mass, i.e., other Molidae species and the beluga sturgeon Huso huso. Overall, we conclude that M. alexandrini is the only extant bony fish species we could confirm that exceeds 2000 kg, and that basic biological information is generally not collected when very large molid specimens occasionally are stranded or are caught. Finally, we confirm that the world's heaviest extant bony fish specimen actually weighed was a female M. alexandrini (2300 kg, 272 cm total length) captured from Kamogawa, Chiba Prefecture, Japan, on August 16, 1996.
世界上现存最重的硬骨鱼长期以来一直被认为是翻车鱼 Mola mola（翻车鲀科）。然而，最近的分类学研究表明，世界纪录标本（2300 公斤）实际上是一条被错误鉴定的巨型翻车鱼 M. alexandrini。此外，翻车鱼属的分类学混淆历史，加上媒体和文献中流传的轶事大小信息，导致了非常大的翻车鱼标本的物种身份和实际重量存在不确定性。在这项研究中，我们搜索了报道体重超过 2000 公斤的翻车鲀标本记录，重点是西北太平洋和西南太平洋。对于每个标本，我们审查了物种鉴定，并评估了信息的可靠性，包括标本是否实际称重。在发现的 15 个标本中，我们鉴定出 1 个 M. mola 和 14 个 M. alexandrini，发现只有 5 个标本实际称重（1 个去除内脏）。此外，我们从文献和博物馆标本中收集了已验证的 M. alexandrini 标本的长度-重量数据，并建立了该物种的第一个长度-重量关系[体重（kg）=1.1×10×总长度（cm）（29-330 cm 总长度，n=20）]。这些发现是在其他据称体重超过 2000 公斤的现存硬骨鱼类物种的背景下讨论的，即其他翻车鲀科物种和白鲸 Huso huso。总的来说，我们的结论是，M. alexandrini 是我们能够确认超过 2000 公斤的唯一现存硬骨鱼类物种，并且当非常大的翻车鲀标本偶尔搁浅或被捕时，通常不会收集基本的生物学信息。最后，我们确认世界上最重的现存硬骨鱼类标本实际上是一条 1996 年 8 月 16 日在日本千叶县馆山市捕获的雌性 M. alexandrini（2300 公斤，总长度 272 厘米）。
