I ate ten of these with Ocean Sight active and got 3-5 energy. Assuming the 2-4 energy yield is all from trials without Ocean Sight, looks like it's adding +1 to energy gains from these.
Data points (ocean symbiosis): 3, 4, 3, 4, 3, 5, 4, 4, 3, 3 4, 4, 4, 5, 5, 3, 4, 5, 5, 3 3