Occurrence of Pelagic Sargassum In Waters of the U.S. Gulf of Mexico In Response To Weather-Related Hydrographic Regimes Associated With Decadal and Interannual Variability In Global Climate

Document Type

Article

Publication Date

1-1-2018

Department

Coastal Sciences, Gulf Coast Research Laboratory

School

Ocean Science and Engineering

Abstract

© 2018, National Marine Fisheries Service. All rights reserved. Pelagic species of Sargassum, surface drifting macroalgae, occur in continental shelf and deep basin waters across the Gulf of Mexico (GOM). They often accumulate in mats and “windrows” to form a structured habitat that serves as a source of food and refuge for a diverse assemblage of fish and invertebrates. Long-term temporal data on the distribution and abundance of Sargassum species in the GOM are lacking, but there is a time series of occurrence of those species across the U.S. GOM (USGOM) associated with ichthyoplankton surveys conducted by the Southeast Area Monitoring and Assessment Program. The seasonal presence of Sargassum species in regions of the USGOM was compared under contrasting weather-related hydrographic regimes using nonparametric tests (Krus-kal–Wallis H test, Mann–Whitney U test, Wilcoxon signed rank test). Phases of the Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO) along with El Niño–Southern Oscillation (ENSO) events influenced seasonal presence of Sargassum species across the area of study. Occurrence of Sargassum species was highest under the coupled warm AMO and neutral NAO phases and cold ENSO events and was associated with physical and biological processes that transported the macroalgae to the USGOM and maintained them over time.

Publication Title

Fishery Bulletin

Volume

116

Issue

1

First Page

93

Last Page

106

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