On self awareness:

Cognitive ethologist pioneer, the late Donald R. Griffin, formerly of Harvard University, suggested in his book "Animal Minds," (University of Chicago Press, 1994) that when an animal hid itself from view, it was demonstrating self awareness. He described how naturalist Lance Olsen, president of the Great Bear Association, reported grizzly bears seeking places from which they could watch hunters while remaining hidden. 

Other early observers such as William Wright (1909) and Enos Abija Mills (1919) reported thatgrizzly bears tried to avoid leaving tracks. The researchers concluded that these bears were aware of being present and observable, as well as creating effects ― their tracks ― through their movements, which could be seen by others. 

The sharks' intentional way of using the visual limit to remain concealed is in the same category, and suggests that sharks, too, are aware of being present and observable, and hence self-aware to that degree.