Bayesian inference was used to estimate the main population parameters (sex ratio, L₅₀, LWR and somatic growth) and to evaluate sexual dimorphism and growth patterns (isometric/allometric and monophasic/biphasic growth) of Astyanax paranae of the Upper Paraná River. This study brings three statistical differentials: (a) the reparametrisation of the logistic model as a function of L₅₀; (b) the reparameterisations of the LWR models based on the exponential of a piecewise linear regression to evaluate the hypotheses of polyphase growth; and (c) the first application of the recently proposed somatic growth models based only on length data to real data, as well as its expansion and generalisation. The models estimated L₅₀ of females at 37.75 mm and sex ratio at 1.4 females per male. LWR models showed that both sexes presented biphasic growth with a lower increase in weight for males in first stanza. In second stanza, both sexes presented a greater increase in weight. Growth models showed that the growth rates were low, equal for both sexes in early life and slightly higher for females after the eighteenth months old. The studied population inhabits streams, therefore being exposed to constraining conditions that can limit the expression of their whole growth potential since they prioritise energy allocation for reproduction and survival, including reducing L₅₀ in order to ensure the maintenance of the population. Finally, the complex biological patterns that arose from the proposed LWR and growth models demonstrated high potential and applicability for population studies.

中文翻译：

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基础种群生态学研究的新方法：揭示栖息在河流中的小型Characidae的更复杂模式

贝叶斯推断被用来估计主要种群参数（性别比，L ₅₀，LWR和躯体生长）并评估帕拉纳河上游的Astyanax paranae的性二态性和生长方式（等距/异位和单相/双相生长）。这项研究带来了三个统计差异：（a）作为L ₅₀的函数的逻辑模型的重新参数化; （b）基于分段线性回归的指数对LWR模型进行重新参数化，以评估多相生长的假设；（c）最近提出的仅基于长度数据到实际数据的体细胞生长模型及其扩展和泛化的首次应用。型号估计为L ₅₀女性为37.75毫米，性别比为每男性1.4女性。LWR模型显示，在第一个节中，男性和女性都呈现双相生长，而体重增加较低。在第二节中，两个性别的体重都有较大增加。生长模型表明，生长速度很低，生命早期两性均相等，而在十八个月大以后，女性的生长速度略高。被研究的种群居住在河流中，因此受到限制条件的限制，因为它们优先考虑能量分配以进行繁殖和生存，包括降低L ₅₀，从而限制了其整个生长潜力的表达。为了确保人口的维持。最后，由拟议的轻水堆和生长模型引起的复杂的生物学模式证明了其在人口研究中的巨大潜力和适用性。