Moored current meter observations complimented by conductivity-tempera
ture-depth (CTD) profiles and shipboard acoustic Doppler current profi
ler measurements have revealed two distinctly different coastal circul
ation patterns south of the island of Barbados, West Indies, in the sp
rings of 1990 and 1991. In the first year an abrupt increase in speed
and change in direction of the currents south of the island was found
to be associated with a large, anticyclonic, horizontally sheared circ
ulation and a marked variation in temperature-salinity characteristics
. The shift in currents was also accompanied by the incursion of a sha
llow pool of low-salinity water, a strong internal semidiurnal tidal s
ignal, and a change in the location of larval fish assemblages west of
the island. Rapid variations in current speed and direction were also
observed in 1991, though less persistent than in the previous year. I
n this year the island was at one time completely surrounded by a larg
e, shallow pool of low-salinity water. A comparison was made of the 19
90 hydrographic observations with CTD data from the National Oceanogra
phic Data Center archive for the region 0 degrees-20 degrees N, 40 deg
rees-60 degrees W. This suggests that the variation in hydrographic ch
aracteristics was due to the intrusion of a water mass of North Brazil
Current origin which displaced the ambient North Atlantic Subtropical
Underwater around the island. Several recent studies have demonstrate
d that mesoscale anticyclonic eddies formed near the retroflection reg
ion of the North Brazil Current can be advected toward the eastern Car
ibbean before being dissipated. It is concluded that the most likely c
ause of the observed high-energy event in 1990 was the passage of such
an eddy past Barbados.