A mother with calf were coming down the beach and she elected to bear out to sea and swim right by me. She remained on the surface until she passed me by.

After she hooked by me, she went under the surface and snortly therafter, the calf surfaced further off and went back down. The calf was likely swimming along side its mother but below the surface and on the far side of her. The calf is seen in the last image, below: