Why does the old man sympathize with the turtles?

Fom the text:

He had no mysticism about turtles although he had gone in turtle boats for many years. He was sorry for them all, even the great trunk backs that were as long as the skiff and weighed a ton. Most people are heartless about turtles because a turtle’s heart will beat for hours after he has been cut up and butchered. But the old man thought, I have such a heart too and my feet and hands are like theirs. He ate the white eggs to give himself strength. He ate them all through May to be strong in September and October for the truly big fish.