Colonies of Montastrea annularis line near La Parguera, Puerto Rico, and may be 700 years old. Time series from 1964 to 1982 of Δ13C and Δ18O from a continuous core of these corals are compared to an adjacent environmental record. At the intraannual level, Δ18O correlates well with water temperature. Changes in the amplitude of the Δ18O signal between 1967 and 1976 are attributed to sampling frequency but may be also due to environmental changes such as salinity. Average annual Δ18O, Δ13C and sea surface temperature show similar trends for the period from 1964 to 1982 but especially from 1969 onwards. Changes in average annual values during this time interval are most likely due to water mass changes brought about by interannual variability of the North Atlantic circulation. Since water temperatures at La Parguera are representative of changes occurring in the wider Caribbean, the isotope record from La Parguera corals could be used as a proxy for large-scale environmental changes beyond the historical record through the Little Ice Age. ¿ American Geophysical Union 19