The extraction process of nucleoprotein and protamine from freshwater fish spermary was studied.

研究淡水鱼精巢中的核蛋白和鱼精蛋白的提取工艺。

These fish could be categorized into four types, including estuarine fishes, marine fishes, diadromous fishes and of freshwater fishes.

这些鱼类分为4个主要生态类型，包括河口性鱼类、近海鱼类、江海洄游型鱼类和淡水鱼类。

Tuna is not a freshwater fish.

金枪鱼不是淡水鱼。

European freshwater fish resembling the roach.

类似于斜齿鳊的欧洲淡水鱼。

Freshwater fish populations are in precipitous decline.

淡水鱼数量急剧下滑。