Which of the following is a disadvantage of living in a shoal?

Living in a shoal presents several advantages, but one notable disadvantage is the higher susceptibility to disease. This occurs because the close proximity of individuals within a shoal can lead to the rapid spread of pathogens. When fish or other organisms are packed closely together, an illness in one member can easily infect many others, as they may share the same water and environments where pathogens thrive.

On the other hand, the benefits of shoaling, such as increased opportunities for finding mates, lower energy expenditure during swimming due to reduced drag from moving in unison, and enhanced safety against predators through sheer numbers, are significant factors that promote this behavior among aquatic species. However, the trade-off of increased disease transmission is a critical consideration for organisms that choose to shoal.