What type of data is typically collected during an electrofishing survey?

During an electrofishing survey, it is essential to gather a comprehensive understanding of the aquatic ecosystem, which prominently includes species composition and size distribution. This type of data allows researchers and managers to assess the diversity of fish species present in a given water body, understand population dynamics, and evaluate the size distribution for insights into growth rates, reproductive success, and overall health of fish populations.

Species composition refers to the variety of different fish species captured during the survey, which can indicate the ecological balance of the habitat, while size distribution provides valuable information about age classes within a population, highlighting recruitment success and potential overfishing concerns. Accurate collection of both data points is crucial for effective fishery management, conservation efforts, and habitat assessments.

In contrast, the other options, while relevant to different aspects of aquatic studies, do not provide the same breadth of information as species composition and size distribution. Water temperature can influence fish behavior and health, but alone, it doesn't characterize the entire population. Fish health metrics are important but are only one part of the picture and do not encompass species diversity or population structure. Environmental conditions might affect fish populations but do not directly assist in understanding the fish community composition and its dynamics. Thus, option B is the most comprehensive and informative choice