Manatees in the St. Johns

So I was riding my bike in San Marco (Jacksonville) and went by a little creek off the St. Johns River. I saw tons of splashing and commotion in the water. There were about a dozen manatees in the water. This was by far the most active I've ever seen the endangered mammals. I called my parents and asked them to bring my camera. Too bad it was overcast and the water was murky, it made the shots hard to get because the animals blend in well with the tint of the water. I used my D50 with my Tamron 28-105mm f./ 2.8. The ISO was between 400 and 800 because it was a gloomy day. Aperture probably around f./4 and I used the fastest shutter speed I could.