Townsend Cromwell

Townsend Cromwell

The Thermal Dome was detected in 1948 for the first time by bathythermographs located on ships that travelled from California to Panama. Townsend Cromwell scientifically described the Thermal Dome in 1958 in the Inter American Tropical Tuna Commissions’ newsletter1 where he indicated that “this area should be referred to as the Costa Rican Thermal Dome, or for short, simply as: the Dome”.

Since the nineteen fifties, the Dome has been observed and studied due to the productive tuna fishery that developed in the region. Multiple expeditions partially sampled it, most notably the Costa Rican Thermal Dome Expedition in 1959 carried out by the Tuna Investigation Program of the Scripps Oceanographic Institution and the Mexican DOME expeditions between 1979 and 19822.


1 Cromwell, T. 1958. Thermocline Topography, horizontal currents and “ridging” in the Eastern Tropical Pacific. IATTC Bulletin No. 3.
2 Fiedler, P. C. 2002. The annual cycle and biological effects of the Costa Rica Dome. Deep Sea Research Part I: Oceanographic Research Papers Vol. 49(2): 321-338.