Aggressive interactions are ubiquitous among animals. They are either directed towards heterospecifics, like predators or competitors, or conspecifics. During intraspecific encounters, aggression often serves to establish hierarchies within the social group. Thus, in order to understand the mechanisms mediating social organization, it is important to comprehend the escalation and avoidance of aggressive behaviour. Overt aggressive interactions are costly not only in terms of increased risk of injury or death, but also due to opportunity costs and energy expenditure. In order to reduce these costs, animals are expected to communicate their strength and aggressive motivation prior to fights. For this purpose, they use different means of communication in various sensory modalities, that is visual, acoustic, chemical, mechanosensory and electric cues. These different modalities can convey different or similar information, underlining the importance of understanding the multimodal communication of aggression. Thus far, most studies on signalling during aggressive encounters have focussed on visual or acoustic cues, most likely as these are the two modalities predominantly used by humans. However, depending on the species’ ecology, visual or acoustic cues might play a minor role for many species. Especially in aquatic systems, visual communication is often hampered due to high levels of turbidity or limited light conditions. Here, alternative modalities such as chemical, mechanical or electrical cues are expected to play a prominent role. In this review, I provide an overview of different modalities used during aggressive communication in aquatic organisms. I highlight the importance of studying the role of multimodal communication during aggressive encounters in general and discuss the importance of understanding aquatic communication in the light of conservation and animal welfare issues.

中文翻译：

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水生环境中的积极沟通

积极的互动在动物中无处不在。它们要么针对异种，如捕食者或竞争者，要么针对同种。在种内遭遇期间，攻击性通常有助于在社会群体内建立等级制度。因此，为了理解中介社会组织的机制，理解攻击行为的升级和避免是很重要的。公开的攻击性互动不仅会增加受伤或死亡的风险，而且还会因为机会成本和能量消耗而付出高昂的代价。为了降低这些成本，动物应该在打架之前传达他们的力量和攻击动机。为此，他们在各种感官模式中使用不同的交流方式，即视觉、听觉、化学、机械感觉和电提示。这些不同的方式可以传达不同或相似的信息，强调了理解攻击性的多模式交流的重要性。到目前为止，大多数关于攻击性遭遇期间信号的研究都集中在视觉或听觉线索上，因为这很可能是人类主要使用的两种方式。然而，根据物种的生态，视觉或听觉线索可能对许多物种起到次要作用。特别是在水生系统中，由于高浊度或有限的光照条件，视觉交流经常受到阻碍。在这里，化学、机械或电提示等替代方式有望发挥重要作用。在这篇评论中，我概述了在水生生物的积极交流过程中使用的不同方式。