Sentinel Crab Macrophthalmus Sulcatus (IMAGE) Royal Netherlands Institute for Sea Research Caption The most abundant crab in Barr Al Hikman is the sentinel crab Macrophthalmus Sulcatus. Literally billions of these crabs live in the area. It is an essential food source for many shorebirds that winter in Barr Al Hikman. ©Jan van de Kam Credit ©Jan van de Kam Usage Restrictions credit photographer License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.