CRABS (BRACHYURA) OF THE GULF OF MEXICO

16 Lawrence W. Powers
FIG. 3. Location of major coral reefs and other features of the Gulf of Mexico, derived from
several sources, including Lynch (1954). Dashed line represents the 100 fathom (600 feet)
isobath.
1—Florida Keys
2—Dry Tortugas
3—Apalachicola Bay and Cape San Bias
4—Mississippi River Delta
5—East and West Flower Garden Banks, off Texas
6—Seven and One-Half Fathom Reef, off Padre Island
7—Pink Shrimp Grounds in Campeche Bay
8—Alacran Reef on Campeche Bank
of Yucatan, eastern Mexico, and eventually, converge with other currents off
Texas. Central entering currents flow northwest, into region 3 (Figure 1). The
most complex patterns occur as the eastward currents diverge and converge
in seasonal patterns of loops. Much of the resultant flow sweeps through the
Straits of Florida to emerge into the Atlantic as the warm, northward moving
Gulf Stream. Other loops circulate up the west coast of Florida, reaching as far
as the Mississippi delta in the winter (Figure 4B). Although these large scale
current diagrams do not indicate the complexity of water movements in the Gulf
region, nor do they allow one to evaluate the spatial and temporal variations in
local currents that might be used for the migration of larval crabs, Figure 4 (after
Leipper, 1954) does indicate the successive relationship between Caribbean, Gulf,
and western Atlantic faunal provinces, respectively. Undoubtably, many western