The Havana littoral, an area of distribution for Physalia physalis in the Atlantic Ocean

Abstract

The hydrozoan Portuguese man-of-war (Physalia physalis) is distributed throughout the Havana littoral zone, which is one of the circulation points of the currents that form the North Atlantic Subtropical Gyre run. For the first time, a study was conducted monthly from May 2018 through May 2019 to better understand the temporal and spatial variation of P. physalis in this region. This study covered five beaches in Havana (Cojímar, Bacuranao, Tarará, Mégano and Santa María). Transects of 50 m were located parallel to the shoreline and the colonies that arrived at the intertidal zone were counted. The colonies of P. physalis were mostly observed in May 2018 (80), November 2018 (110), December 2018 (132), January 2019 (152) and March 2019 (126), which coincided with the dry season in Cuba. This season was related to the presence of cold fronts and a negative average magnitude of the Arctic Oscillation Index (-0.05). The beaches with a relatively linear shape had a higher number of arrivals (549 colonies) than the beaches with a horseshoe shape (109 colonies). In addition, the highest number of colonies was associated with wind velocity above 33 km.h−1 (especially northerly wind), wave height above 1.5 m, and temperatures below 30 °C.