Excerpts from Jim Conrad's
from the May 22, 2011 Newsletter issued
from written at Mayan Beach
Garden Inn 20 kms north of Mahahual, Quintana Roo, México
SERGEANT MAJOR IN A COTTAGE CHEESE BOWL
At low tide interesting critters turn up in tide pools -- depressions in rock and sand holding water when the tide goes out. Here the most frequently appearing fish in tide pools is the half-finger-long one shown above.
I got that picture by scooping the fish into a cottage cheese bowl washed onto the beach, then slowly dribbling water out until the fish lay on his side in the dish's bottom.
In Humann & Deloach's Reef Fish Identification: Florida Caribbean Bahamas it was easy enough to match the fish with a picture, since it's one of the most abundant and best known reef fish in the Caribbean, one often seen while snorkeling, and one often included in tropical fish aquaria. It's the Sergeant Major, ABUDEFDUF SAXATILIS, in the family of fish comprising damselfishes and clownfishes. They're called Sergeant Majors because of their militaristic stripes.
Sergeant Majors grow to about 9 inches (23 cm), so my inch-long catch is a juvenile. However, in our tide pools, all I found were juveniles, and the one I caught was the largest of all. I read how hundreds of Sergeant Majors may school around reef caves, old shipwrecks and the like, how they change colors to camouflage themselves, how the males when they guard their red or purple patches of eggs turn dark bluish... and begin picturing a complex, endearing little fish. I feel guilty for having caused one to lie so nakedly in the bottom of a trashy cottage cheese container.
Sergeant Majors live in reef and rocky environments in the Atlantic Ocean -- from Canada to Uruguay in the west, and from western Africa to Angola in the east.
There's a lot of life-history info about this fish at http://www.sms.si.edu/irlspec/Abudefduf_saxatilis.htm.