September, 2015 ~ We’ve been on Bonaire for the past three weeks as Buddy Dive Resort’s resident naturalists. So how have we been spending our time when we’re not talking fish with other divers? We’ve started working on an update to our Reef Fish Behavior book and have a list of behaviors we want to add. For a good part of this week, we’ve been watching Sergeant Majors (Abudefduf saxatilis), ubiquitous little damselfish. More specifically, we’ve been waiting for their eggs to hatch. At a hundred minutes at a time (about all the time the air in my 63 cf tank will last at 25 feet) I’ve starting feeling like Horton in Horton Hatches a Who.
After last night’s marathon, Ned showed me how he’d passed the time: watching a crab feed on the Sergeant Major eggs:
Sergeant Major eggs are about the size of a sesame seed. They start out red and full of yolk. As the embryo develops, they become clear and a little silvery. Some of the eggs in this image are either freshly laid or didn’t get fertilized; the others are not quite ready to hatch but you can see the eyes of the developing Sergeant Major embryos: