Ishimatsu Atsushi, Mai Hieu Van, Martin Karen L M
Organization for Marine Science and Technology, Nagasaki University, 1551-7 Tairamachi, Nagasaki 851-2213, Japan.
Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyomachi, Nagasaki 851-8521, Japan.
Integr Comp Biol. 2018 Dec 1;58(6):1064-1085. doi: 10.1093/icb/icy108.
Although fishes by nature are aquatic, many species reproduce in such a way that their embryos are exposed to air either occasionally or constantly during incubation. We examine the ecological context and review specific examples of reproduction by fishes at the air-water interface, including fishes that do and do not breathe air. Four modes of reproduction at the air-water interface are described across 18 teleost orders, from fresh water, estuaries, and sea water. Mode 1, the most common type of reproduction by fishes at the air-water interface, includes 21 families of mostly marine teleosts that spawn in water onto a substrate surface, on vegetation, or into hollow objects such as shells that will later be continuously or occasionally exposed to air. Although the eggs are emerged into air, many of these species do not emerge into air as adults, and only about half of them breathe air. Mode 2 involves six families of freshwater fishes setting up and guarding a nest and guarding on the water surface, either with bubbles or in vegetation. Most of these species breathe air. In Mode 3, annual killifishes in at least two families in seasonally dry habitats bury eggs in mud in temporary pools, then die before the next generation emerges. These species neither guard nests nor breathe air. Mudskippers (Gobiidae) breathe air and use Mode 4, excavating burrows in a soft substrate and then storing air in a subterranean chamber. In a variation of Mode 4, eggs are placed on bubbles within a nesting burrow by swamp eels (Synbranchidae). No fishes from basal taxa are known to place their embryos where they will be exposed to air, although most of these species breathe air as adults. The widespread but still rare, diverse forms of fish reproduction at the air-water interface across a broad taxonomic spectrum suggest repeated independent evolutionary events and strong selection pressure for adult fishes to protect their embryos from hypoxic waters, aquatic predators, pathogens, and UV radiation. Air-breathing by adult fishes appears to be de-coupled from air exposure of developing embryos or aerial emersion of adults during spawning.
尽管鱼类天生生活在水中，但许多物种的繁殖方式使得它们的胚胎在孵化过程中会偶尔或持续暴露于空气中。我们研究了这种繁殖方式的生态背景，并回顾了鱼类在空气 - 水界面繁殖的具体例子，包括呼吸空气和不呼吸空气的鱼类。本文描述了来自淡水、河口和海水环境的18个硬骨鱼目在空气 - 水界面的四种繁殖模式。模式1是鱼类在空气 - 水界面最常见的繁殖类型，包括21个主要为海洋硬骨鱼的科，它们在水中将卵产在基质表面、植被上或诸如贝壳等中空物体中，这些物体随后会持续或偶尔暴露于空气中。尽管卵暴露于空气中，但这些物种中的许多成年后并不暴露于空气中，并且只有大约一半的物种呼吸空气。模式2涉及6个淡水鱼科，它们在水面上用气泡或在植被中建立并守护巢穴。这些物种中的大多数呼吸空气。在模式3中，季节性干旱栖息地中至少两个科的一年生鳉鱼将卵埋在临时水池的泥中，然后在下一代孵化之前死亡。这些物种既不守护巢穴也不呼吸空气。弹涂鱼（虾虎鱼科）呼吸空气并采用模式4，即在软质基质中挖掘洞穴，然后将空气储存在地下腔室中。在模式4的一种变体中，沼泽鳗鱼（合鳃鱼科）将卵产在巢穴洞穴内的气泡上。虽然已知基础分类群中的大多数成年鱼类呼吸空气，但没有已知的基础分类群物种将其胚胎放置在会暴露于空气中的地方。广泛但仍然罕见、多样的鱼类在空气 - 水界面的繁殖形式表明，在广泛的分类谱系中存在反复的独立进化事件以及成年鱼类为保护其胚胎免受缺氧水域、水生捕食者、病原体和紫外线辐射的强烈选择压力。成年鱼类的空气呼吸似乎与发育中胚胎的空气暴露或产卵期间成年鱼的空中出现脱钩。
