Volume 71

Holopelagic Sargassum and the Complexities of Predicting Influxes and Impacts on Pelagic Fisheries of the Lesser Antilles

Donald Johnson;Hazel Oxenford;Shelly-Ann Cox;James Franks
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Date: November, 2018

Pages: 300-305

Event: Proceedings of the Seventy Annual Gulf and Caribbean Fisheries Institute

City: San Andres Island

Country: Colombia


Barbados, at 13oN, is located near the separation between water masses of the North Atlantic Gyre and the system of equatorial currents whose origin, in part, is in the South Atlantic. Seasonal and inter-annual variations in local currents and water masses at Barbados are high due to variations in the boundary between the gyre and the equatorial current system. In observations and models, this boundary occurs near 15oN with considerable fluctuation. Local Sargassum influx events can be back-tracked to a broad range of locations in the equatorial Atlantic, dependent on season and dominance of either system of currents. Complex forcing mechanisms driving seasonal variations in local Sargassum coverage include the Amazon River discharge, equatorial current branching and seasonal winds over the North Atlantic. We examined the impact of this tropical Sargassum bloom on major pelagic fisheries in Barbados with the result of a nearly 50% reduction of catch when Sargassum is present. Satellite-derived estimates of Sargassum coverage together with flyingfish, dolphinfish, and wahoo catch data over the last two decades illustrate the complex relationship between Sargassum and pelagic fisheries. These complex relationships regarding influxes and impacts on the pelagic fisheries will need further resolution to better inform future policy and management decisions towards adaptation of the fisheries sector. Efforts to predict Sargassum influx to the Lesser Antilles several months in advance are described.

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