Look at every reconstruction of the landing beaches, and (assuming they get the obstacles correct) you will see mines strapped to some of them. Yeah, right.
Here's the thing: sand water corrodes landmines; quickly. There are notes in the original records that the Germans were VERY short of salt water resistant mines, so they were specifically told to keep them in storage until a landing seemed imminent, and only them put them out. There may have been a handful; of them deployed in the sea area, but consider that when a mine corrodes it can damage the firing system, and make the mine very dangerous to disarm or move. If you have these unstable mines out there, would you want to go change one out knowing that the fuse could trigger for no reason? Didn’t think so. The only safe way to deal with one would be to blow it in place, which would also blow the obstacle, and mean you'd have to dig out a new hole and pound in a new one. I can’t say for sure how many mines might have been on the beach obstacles that day, but it was a lot less than people would have you think. I suspect most of those craft that "hit a mine" near the beaches were actually just hit by either a mortar or shell.
If you look at photos that actually show mines on an obstacle, most of them are from German propaganda photos. Of course they would put them up for the photos.
Now let's look at one of the most famous quotes of D-day: "the sea ran red with blood." How very old testament. Now of course if a guy is cut up he'll bleed. And it will redden the water around him. But think about how many gallons of water that blood gets dispersed in. If he was on the beaches you could see water trickling down to the sea and it was a small amount so I am sure it turned red. However one D-day veteran family told me their dad" landed on D+1, and the water was still red with blood." A day later? I seriously doubt it. That's the kind of implanted memory you get from hearing too many references to that sort of thing, or in movies.
I recall one 29th vet (Harold Baumgartener, and MD) once told me the whole red water was hogwash. He never saw anything like that. Of course one of the reasons he gave was that many of the wounds were self cauterized due to the heat of the projectile, which is something that just is not true in many cases, but that was his explanation of why he didn’t see bloody water.
If you wonder how long it would take to disperse the blood, go pour 10 pints of fake blood into an ocean. See how long it takes before you can't see it. Of course if you know anyone at a blood bank and can get expired blood, that's even better! If you pour it on the beach it'll drain down to the sea, but dump it in the ocean and it'll soon be gone.
The sea red with blood is another one of those "go to phrases," just like "bodies stacked like cordwood."