Age and growth of the crocodile shark, <i>Pseudocarcharias kamoharai</i>, in the Eastern Tropical Pacific Ocean
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The age, growth, and longevity parameters of crocodile shark, <i>Pseudocarcharias kamoharai</i>, from Santa Rosa, Ecuador were estimated. A number of 328 organisms were analyzed, 158 females (69 to 117 cm total length, TL) and 170 males (72.5 to 110 cm TL). The relationship between the vertebra's radius and TL was moderate (r<sup>2</sup> = 0.63), indicating a relation between structure growth and the organism's size. Females were four to 14 years old and males were four to 12 years. The multimodal approach determined that the suitable equations were: The Von Bertalanffy growth function model with a fixed L<sub>0</sub> (45.5 cm TL), VBGM2P (L<sub>∞</sub> = 118.4 cm cm TL, k = 0.15) for combined sexes with a weight of evidence (W<sub>i</sub>) to its favour of 43.9%; logistic growth model (L<sub>∞</sub> = 109.5 cm TL, k = 0.41, L<sub>0</sub> = 33.1 cm TL) for females with Wi = 28.4% and VBGM2P (L<sub>∞</sub> = 110.4 cm TL, k = 0.16) for males with a Wi = 39.4%. No model obtained a sufficient evidence to be declared the best adjusted. The calculated longevities were 18 years for combined sexes, 16 for females, and 14 for males.
本研究对采自厄瓜多尔圣罗萨地区的铠鲨（Pseudocarcharias kamoharai）的年龄、生长及寿命参数进行了估算。共分析328尾个体，其中雌性158尾（总长度(total length, TL)范围为69~117 cm），雄性170尾（TL范围为72.5~110 cm）。椎骨半径与总长度的相关性中等（决定系数r²=0.63），表明该骨骼结构的生长与个体体型存在关联。雌性个体年龄为4~14龄，雄性个体为4~12龄。多模型推断方法确定适配的生长方程如下：针对两性混合样本，采用固定初始总长度L₀=45.5 cm的双参数冯·贝塔朗菲生长函数模型（VBGM2P），其证据权重（W_i）为43.9%，渐近总长度L∞=118.4 cm，生长系数k=0.15；针对雌性个体，采用逻辑斯蒂生长模型，其渐近总长度L∞=109.5 cm、生长系数k=0.41、初始总长度L₀=33.1 cm，证据权重W_i=28.4%；针对雄性个体，采用VBGM2P模型，其渐近总长度L∞=110.4 cm、生长系数k=0.16，证据权重W_i=39.4%。未发现任何模型可被认定为最优拟合模型。计算得到的整体寿命为18龄，雌性为16龄，雄性为14龄。
