Abstract The research focuses mainly on the ichthyoplankton of the Baltic deeps – the inflow route from the North Sea. The ichthyoplankton was represented by eggs and larvae of nine fish species: sprat, cod, herring, European flounder, fourbeard rockling, longspined bullhead, straightnose pipefish, sand goby and great sandeel. The species composition of ichthyoplankton varied depending on the location of a given site – the number of taxa ranged from one to five. The Slupsk Furrow was the most diversified area in terms of the number of taxa, while the highest abundance of ichthyoplankton occurred in the Bornholm Basin. The sprat clearly dominated and inhabited all the surveyed depths. Of the remaining species, only cod eggs as well as eggs and larvae of the fourbeard rockling significantly contributed to this formation. They occurred within their main spawning grounds (Bornholm Deep in the near-bottom layers) and secondary spawning grounds (Slupsk Furrow and Gdansk Deep) where salinity and oxygenation of water favored their development. Biometric research has shown that the diameter of eggs was within the size range typical of the Baltic Sea.

中文翻译：

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沿波罗的海南部环境梯度的浮游鱼类组成和丰度的变化

摘要 研究主要集中在波罗的海深海浮游鱼类——北海的流入路线。浮游鱼类以九种鱼类的卵和幼虫为代表：鲱鱼、鳕鱼、鲱鱼、欧洲比目鱼、四须鲽鱼、长刺牛头鱼、直鼻尖嘴鱼、沙虾虎鱼和大鲱鱼。浮游鱼类的物种组成因特定地点的位置而异——分类群的数量从 1 到 5 不等。就分类群数量而言，斯卢普斯克沟是最多样化的地区，而博恩霍尔姆盆地则是浮游鱼类丰度最高的地区。鲱鱼明显支配并栖息在所有调查的深度。在其余物种中，只有鳕鱼卵以及四须鲭鱼的卵和幼虫对这种形成有显着贡献。它们发生在它们的主要产卵地（近底层的博恩霍尔姆深海）和次产产卵地（斯卢普斯克沟和格但斯克深水）内，那里的盐度和水的含氧量有利于它们的发育。生物识别研究表明，鸡蛋的直径在波罗的海典型的大小范围内。