Most marine animals rely on sound for survival and depend on unique adaptations that enable them to communicate, protect themselves, locate food, and navigate underwater. Zoologists may study the sounds that marine animals make, how they produce them, and how these sounds are used in behaviors such as reproduction, feeding, and communication.
The ocean is full of both natural and anthropogenic (human-made) sources of sound. Therefore, zoologists may also investigate the potential effects of anthropogenic sound on marine animals. Scientists use data on the way in which the animals respond to similar sounds and sound levels to estimate how much the sound might affect their behavior. Background noise and specific sound sources might impact marine animals in several ways. The potential impacts include altering behaviors, preventing marine animals from hearing important sounds (masking), causing hearing loss (temporary or permanent), or damaging tissues.
Zoologists may use acoustic tools and methods to study marine animal distribution and abundance . For example, each species of whale and dolphin produces distinctive sounds that may include echolocation clicks, calls or songs. Zoologists can listen for these sounds, using tools such as hydrophones, hydrophone arrays, and other passive acoustic sensors, and detect different marine mammal species. Estimating abundance (population size), animal density (number of animals per unit area), and the overall distribution of marine mammals are critical for properly understanding marine mammal ecology as well as making important and effective management and conservation decisions. In a similar fashion, zoologists specializing in fishes (ichthyologists) can listen to fish vocalizations , identify species, and document fish distribution patterns, especially those related to spawning (reproduction). These data provide valuable information to resource managers overseeing natural resource policies on the marine environment.