Pseudoreplication of sound treatments in underwater exposure studies

Abstract

Sound exposure studies require replicated sound treatments for the results to be representative for sound classes in general. Additionally, reused treatments in replicated designs need to be accounted for statistically. The lack hereof is referred to as simple and sacrificial pseudoreplication, respectively, and results should be interpreted accordingly. We quantified the occurrence of these issues and subsequent interpretation of results in 104 underwater sound exposure studies (2019–2023). The majority of the studies (85%) did not replicate sound treatments. From the ones that did, most did not statistically acknowledge the hierarchical structure of the data. Unreplicated treatment designs limit the generalizability of the findings. Nevertheless, only small differences were found in how the results of unreplicated and replicated treatment designs were interpreted. This commentary aims to provide guidance in the design, analysis and interpretation of sound exposure studies, which are equally valid for aquatic and terrestrial research.