374 
Fishery Bulletin 95(2), 1997 
Clearly, we need additional information on how and 
when the biological productivity of Gulf of Mexico 
cyclones may “spin up.” As a corollary, however, we 
need to remember that Gulf of Mexico cyclones are 
analogous but not homologous to Gulf Stream cold- 
core rings. As a consequence of their cyclonic nature, 
Gulf of Mexico cyclones are regions of elevated near- 
surface nutrients but unlike Gulf Stream cold-core 
rings, they are not regions of biological expatriation. 
Studies of the fauna within Gulf Stream cold-core 
rings have documented that because these rings are 
“oases” of temperate slope water that are transported 
into an oligotrophic subtropical central gyre, some 
of their resident fauna succumb to thermal stress as 
the cold-core of temperate origin dissipates by mix- 
ing with the surrounding subtropical water (Wiebe 
et al., 1976; Boyd et al., 1978). In contrast, popula- 
tions of plankton and nekton in Gulf of Mexico cy- 
clones should be sustained (rather than stressed) by 
mixing with surrounding subtropical water and so 
persist as local aggregations of enhanced food sup- 
ply for apex predators that feed on krill-size food. 
Acknowledgments 
Shiptime for this cruise was provided by Texas A&M 
University for graduate student training and re- 
search. We thank John Wormuth and graduate stu- 
dents Luiz Fernandes, Marilyn Yeager, and Wen- 
tseng Lo for making the meter net hauls with us. We 
also thank Larry Rouse and Nan Walker at the 
Coastal Studies Institute at Louisiana State Univer- 
sity in Baton Rouge, LA, for providing the SST im- 
age of 9 March, and Tom Berger at Science Applica- 
tions International Corporation in Raleigh, NC, and 
Don Johnson at the Naval Research Lab in Stennis 
Space Center, MS, for providing the XBT’s. 
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