Massive stranding of Physalia physalis in the Northwestern coast of Cuba

• Main Authors: Eduardo Gabriel Torres Conde, Rosa Elisa Rodríguez Martínez
• Format: Article in Journal/Newspaper
• Language: English; Spanish
• Published: Centro de investigaciones Marinas-UH 2024
• Subjects: beach cast; bloom; dimorphism; health risk; juvenile colonies; Portuguese man-of-war; Geography. Anthropology. Recreation; G; Oceanography; GC1-1581; Climate change; Human health; North Atlantic
• Online Access: https://doaj.org/article/d691ea092a1d4071a858539237cae4db

Historically, Physalis physalis massive stranding events have been infrequent and poorly documented. However, their occurrence can have significant impacts on human health and the stability of coastal ecosystems. In this study, we analyze a massive P. physalis stranding affected Cuba’s NW coast in December 2022. We counted all colonies during the massive event along ~ 3 km coast, within a 5 m stripe. Density, dimorphic form (left/right-handed), and colony size were quantified using 0.25 m2 quadrat placed every 50 m, 10 m from shoreline. Eighty-five people were stung, with 38 having strong allergic reactions, resulting in a health risk. Over ten thousand colonies were recorded, with the highest mean colony density (29.3 per m2) ever reported. The massive stranding coincided with the lowest Arctic Oscillation index (-2.59) in the past 11 years during December, which led to the emergence of northeasterly winds reaching speeds of up to 24 km/h. Wind direction and speed, coupled with the dominance of left-handed colonies (71.4%), suggest the North Atlantic Subtropical Gyre as a possible origin source of the bloom. The high prevalence of juvenile P. physalis colonies (68 %) likely aligns with the autumn breeding season in the northern hemisphere. The potential causes of P. physalis blooms are still poorly understood. Systematic monitoring of the distribution and abundance of this species should be a research priority considering the potential risk to human health and that the blooms could become more frequent in the Atlantic coasts, given climate change and increasing eutrophication of the oceans. Received: 10.08.2023 Accepted: 14.12.2023