A conspicuous band of bare sand averaging about 30 ft in width often separates reefs and beds of sea grasses (Thalassia and Cymodocea) in the Virgin Islands and other islands of the West Indies. This zone of sand appears to be the result of heavy grazinlg by parrotfishes (Scarnts and Sparisomtla) and surgeonfislbes (Acanthuruts) that stay close to reefs for shelter frorm predaceous fishes. Floating sea grass fragnments are eaten by the halfbeak Hemiramiphus brosiliceisis and occa- sionally by the Bermuda chub Kyphosus sectatrix and the triggerfish Melichlthys radulla. Within the beds, the sea grasses are fed upoIn by the simiall residlent parrotfish Sparisonlia radians, the echinoids Lytechinus, Tripuieustes, and D)iadena, the green turtle Cheloniia nziydas, and in part by the queen conch Strom ibuis gigas, and manatee Trichechts tnianiatuts. It is the author's opinion that if the pre-Columbian population of the green turtle could be restored and its fishery properly regulated, the enormous production of the sea grasses in the Caribbean region could be realized more fully for the benefit of man.
[1]
R. Livezey,et al.
Sea Turtles and the Turtle Industry of the West Indies, Florida, and the Gulf of Mexico, with Annotated Bibliography.
,
1951
.
[2]
H. Odum.
Primary Production Measurements in Eleven Florida Springs and a Marine Turtle-Grass Community1
,
1957
.
[3]
K. Strawn.
Factors Influencing the Zonation of Submerged Monocotyledons at Cedar Key, Florida
,
1961
.
[4]
R. Thorne.
Flowering plants of the waters and shores of the Gulf of Mexico
,
1954
.
[5]
J. Bardach,et al.
Transport of Calcareous Fragments by Reef Fishes
,
1961,
Science.