Question

study the structure of the fishes in a shallow waterbody and in a deep waterbody

Answer 1

As part of the Advanced Open Water course a student must complete a deep dive to 100 feet / 30 meters, so for an Advanced Open Water Diver any depth greater than 60 feet / 18 meters is considered deep. Usually, a deep dive is considered to be a dive between 100 feet / 30 meters