There are three bioluminescent bays (bio bays) in Puerto Rico — Mosquito Bay in Vieques, Laguna Grande in the north-east in Fajardo, and La Parguera in the south-west in Lajas. The biobay experience is pretty neat to see — the water glows when the microorganisms in it are agitated. It is said that the Vieques biobay is the brightest (with the most dynoflagellates per gallon). The Fajardo biobay is the second brightest . Finally, there’s the biobay at La Parguera with the least number of dynoflagellates. But what does that mean in comparison to the other biobays?