Seeing Double

I had to rub my eyes today to make sure I wasn't seeing double. Before now, I have only seen these soft spinyshell turtles on their own, as in the post two days ago. Sisters, or mother and daughter, I'm not sure, but they were not aggressive towards each other. 
The males are reportedly considerably smaller and I've never seen one. I suppose the males have no reason to leave the water.

They were spraying stones a good 10 feet or more, whilst creating holes to lay their eggs. I wouldn't like to get in the way!

I cropped in on this image so it may not look like it, but I stayed at distance today to not scare them.