[MARMAM] Offshore Tursiops mother and calves

Good Morning, I am an illustrator pulling together research for a children's picture book about an offshore bottlenose dolphin. I am looking for information on mother and calf activity during deep dives. Do the calves remain on the surface? Do mothers refrain from deep dives while they have young calves? At what age do calves begin to make deep dives? I'd appreciate any information. Thank you for your time. Lindsay