Sharks and rays can get entangled in abandoned fishing gear, leading to injuries or death.

A newly developed underwater ultrasound reveals a fetal shark swimming between the two uteri of its mother.

In addition to detecting unseen organisms in the ocean, studies of environmental DNA can shed light on the genetic structure of marine populations.

Watch scenes from research at the University of South Florida's Mote Marine Laboratory, where scientists saw what happened when they knocked out sharks' electroreception.