Linkage between metabolic ontogeny and cannibalism in perch-like fish and their derivatives

动物静息代谢率M与体质量W之间的关系可用异速生长公式M=Aw^b表示，其中a为质量系数，b为质量指数。质量指数小于1，因为质量比代谢率M/W通常随着体重的增加而降低。这一现象在种间(种间)和种内(种内)都是众所周知的。新陈代谢的个体发生(种内M/W随生长的变化)是一个复杂的过程，在这个过程中可以区分几个阶段。然而，硬骨鱼代谢个体发育的确切性质和生物学意义尚未在硬骨鱼中建立，因为幼体和幼体非常小和脆弱。在这里，我们发现河豚的M/W随着体重的增加而下降，但当达到一定的生长阶段时，它会突然增加，并伴随着严重的同类相食。在呼吸测量中发现，湿体质量在0.0008-3g之间的河豚有四个独立的异速生长公式M/W=aIW^&lt；b-1&gt；其中，质量系数a_i在0.002、0.01和0.1g附近突然或短时间内增加了三倍，但质量指数保持不变(b=0.82)。与这些aI的增加相对应的是有三个食人高峰。随着体重的增加或生长，a_i的增加是不寻常的，但如果仔细进行呼吸测量，在各种硬骨鱼中都会发现a_i。与河豚相似的现象也出现在牙科比目鱼和鲱鱼身上。在自然条件下，这些现象意味着生长能力更快的个体确保更高的存活率，以减少捕食风险。

The relationship between resting metabolic rate M and body mass W of animals is expressed by an allometric formula M=aW^b, where ‘a' is mass coefficient and ‘b' mass exponent. Mass exponent is smaller than unity, because mass-specific metabolic rate M/W usually decreases with increasing body mass. This phenomenon is well known interspecifically (among species) as well as intraspecifically (within a species). The ontogeny of metabolism (intraspecific change of M/W with growth) is a complex process in which several phases can be distinguished. However, the precise nature and the biological meaning of the ontogeny of metabolism have not been established in teleost fishes, because of very small and fragile nature of larvae and juveniles. Here we show that M/W of a puffer fish Takifugu rublipes decreases with increasing body mass, but it increases abruptly accompanying a severe cannibalism when getting to a certain growth stage. We found in respirometry that the puffer ranging 0.0008-3g in wet body mass had four independent allometric formulae M/W=a_iW^<b-1>, in which the mass coefficient ‘a_i' increased three times abruptly or in a short period at around 0.002, 0.01 and 0.1g, although keeping a constant mass exponent (b=0.82). There were three peaks of cannibalism corresponding to these increases of ‘a_i'. Increases of ‘a_i' with increasing body mass or with growth are unusual, but it would be found in various teleost fishes, if careful respirometry were taken. Similar phenomena to the puffer fish were observed in a flounder Paralichthys olivaceus and a mackerel Scomber japonicus. In the natural condition, these phenomena imply that individuals with growing ability more rapidly are assured of higher survival to reduce predatory risk.