Piscadera Bay is situated 4 km West of Willemstad, Curaçao, between two limestone hills which have a height of about 100 m. It is a drowned river system, the entrance of which is almost completely blocked by a bar of coral debris reaching to about 2 meters above sea level. The following parts may be easily distinguished: 1) the Boca or “Outer Bay.” 2) the “Entrance,” and 3) the bay proper or “Inner Bay” (see map, Fig. 147). The Boca or “Outer Bay” is about 200 m wide and 6 m or less deep until (about 100 m off-shore) it reaches the outside border of a coastal platform which rapidly falls to several hundred meters. This sandy Boca is not only submitted to a turbid tidal flow of water from the Inner Bay, but, moreover, suffers from the increasing influence of man which has changed the underwater landscape in various ways.