Adult Blue Shark was filmed venturing deep into the Lagoa de Óbidos lagune. Although only one appears in the video, witnesses say they were two, and that both seemed to be around 2 meters in length.
I couldn´t find the exact location in Lagoa de Óbidos where this was filmed, but it supposedly was near the Braço da Barrosa spot.
Video filmed by Mr. Manuel Torres, and published on Facebook by Apmalo Lagoaobidos.