Giant beaches with unbelievable amount of turtles

i have a problem. i made a new world, i spawned in a jungle, after a few minutes of playing i noticed a giant beach in the middle of jungle, it had a lot of turtles in it and the water generation was pretty buggy, i dont know how can this happen, i played on creative mode without any extra settings on. Please help, you can see the screenshot under the text.

 

turtle party beach