The determination of sex is an important hallmark in the life cycle of organisms, in which the fate of gonads and then the individual sex are defined. In gonochoristic teleost fish, this process is characterized by a high plasticity, considering that in spite of genotypic sex many environmental factors can cause shifts from one to another molecular pathway, resulting in organisms with mismatching genotypic and phenotypic sexes. Interestingly, in most instances, both female-to-male or male-to-female sex-reversed individuals develop functional gonads with normal gametogenesis and respective progenies with full viability. The study of these mechanisms is being spread to other non-model species or to those inhabiting more extreme environmental conditions. Although water temperature is an important mechanism involved in sex determination, there are other environmental stressors affected by the climate change which are also implicated in stress response-induced masculinization in fish. In this regard, the brain has emerged as the transducer of the environment input that can influence the gonadal fate. Furthermore, the evaluation of other environmental stressors or their synergic effect on sex determination at conditions that simulate the natural environments is growing gradually. Within such scope, the concerns related to climate change impacts rely on the fact that many of biotic and abiotic parameters reported to affect sex ratios are expected to increase concomitantly as a result of increased greenhouse gas emissions and, particularly worrying, many of them are related to male bias in the populations, such as high temperature, hypoxia, and acidity. These environmental changes can also generate epigenetic changes in sex-related genes affecting their expression, with implications on sex differentiation not only of exposed individuals but also in following generations. The co-analysis of multi-stressors with potential inter- and transgenerational effects is essential to allow researchers to perform long-term predictions on climate change impacts in wild populations and for establishing highly accurate monitoring tools and suitable mitigation strategies.

中文翻译：

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应激反应轴的激活是环境诱导的鱼类性别可塑性的关键过程。

性别的决定是生物体生命周期中的一个重要标志，其中性腺的命运和个体性别被定义。考虑到尽管存在基因型性别，许多环境因素会导致从一种分子途径到另一种分子途径的转变，从而导致生物体的基因型和表型性别不匹配，因此在淋病硬骨鱼中，这一过程的特点是具有高可塑性。有趣的是，在大多数情况下，雌性变雄性或雄性变雌性的性别逆转个体都会发育具有正常配子发生的功能性性腺和具有完全活力的各自后代。对这些机制的研究正在扩展到其他非模型物种或居住在更极端环境条件下的物种。虽然水温是性别决定的重要机制，还有其他受气候变化影响的环境压力因素也与压力反应引起的鱼类男性化有关。在这方面，大脑已经成为可以影响性腺命运的环境输入的传感器。此外，在模拟自然环境的条件下，对其他环境压力源或它们对性别决定的协同作用的评估正在逐渐增加。在此范围内，与气候变化影响相关的担忧依赖于以下事实：据报道，许多影响性别比例的生物和非生物参数预计会因温室气体排放增加而随之增加，尤其令人担忧的是，其中许多与性别比例相关群体中的男性偏见，如高温、缺氧和酸度。这些环境变化还可以在影响其表达的性别相关基因中产生表观遗传变化，不仅影响暴露个体的性别分化，而且影响后代的性别分化。对具有潜在代际和跨代影响的多压力因素进行共同分析对于研究人员对气候变化对野生种群的影响进行长期预测以及建立高度准确的监测工具和合适的缓解策略至关重要。