"水生生物生态学" can be translated into English as "Aquatic Biology Ecology" or more precisely, "Aquatic Organism Ecology".
"Aquatic" refers to anything related to water.
"Biology" is the study of living organisms, but in this context, when combined with "aquatic," it often implies the broader biological aspects of aquatic environments. However, to specifically emphasize organisms, "organism" is a better choice.
"Ecology" is the study of the relationships between living organisms and their environment.
Thus, "Aquatic Organism Ecology" more accurately captures the meaning of studying the ecology of organisms living in water.