The first 200 meters of the ocean. Sunlight penetrates the first 200 meters making photosynthesis possible. Since much plant life lives here there is also much wildlife. Most ocean animals we are familiar with are found in the epipelagic zone.
From the surface (MSL) down to around 200m (656 ft)
The illuminated surface zone where there is enough light for photosynthesis.
Due to this, plants and animals are largely concentrated in this zone.
Videos
Thsi video - only the first 2 minutes applies to the epipelagic zone.