Sargassum - NOAA RESTORE Science Program

**Linking habitat to recruitment: Evaluating the importance of pelagic Sargassum to fisheries management in the Gulf of Mexico**

This project evaluated the importance of sargassum as a nursery habitat for fish in the northern Gulf of Mexico.

From the seminar “Linking habitat to recruitment: Evaluating the importance of pelagic Sargassum to fisheries management in the Gulf of Mexico”
Presenter: Dr. Frank Hernandez, University of Southern Mississippi

Other Resources

The Team: Frank Hernandez (Lead Investigator, formerly University of Southern Mississippi, now NOAA frank.hernandez@noaa.gov), Chuanmin Hu (University of South Florida), Kevin Dillon (The University of Southern Mississippi), Glenn Zapfe (NOAA), and Walter Ingram (NOAA)

Technical Monitor: Mandy Karnauskas (mandy.karnauskas@noaa.gov)

Federal Program Officer/Point of Contact: Frank Parker (frank.parker@noaa.gov)

This project began in June 2017 and will end in May 2022.

Award Amount: $1,770,853

Why it matters: Sargassum is thought to serve as nursery habitat for recreationally and commercially important fishes in the Gulf of Mexico, such as gray triggerfish and mahi mahi. However, information about the nursery function of Sargassum for juvenile life stages of these fishes is lacking, and managers know little about the environmental factors that drive variability in Sargassum abundance and distribution.

Project Outcome: For this project we used field surveys, remote sensing, and modeling approaches to evaluate the nursery function and fisheries importance of Sargassum in a context useful for resource managers. Our team was successful in accomplishing the goals and objectives of this project. We generated maps of Sargassum distribution and biomass for the Gulf of Mexico, and described Sargassum interannual variability using a time series of remote sensing observations. In doing so we identified two potential “sources” of Sargassum for the Gulf of Mexico (western Gulf of Mexico, northwest Caribbean), and characterized the influence of eddies and frontal regions in determining Sargassum distribution. We collected in situ observations during four 9-day research cruises in the northern Gulf of Mexico, including a suite of environmental data and samples (e.g., nutrients, fishes, invertebrates, Sargassum) for analyses.

Summary of Outcome: These data were used to quantify spatial and temporal patterns in Sargassum-associated fish abundance, taxonomic richness, and diversity. Food web dynamics were described using traditional diet analyses for a suite of managed species (gray triggerfish, greater amberjack, lesser amberjack, almaco jack, and tripletail). Bulk stable isotope analyses and compound specific stable isotope analyses were used to further characterize trophic pathways associated with Sargassum communities. We developed Sargassum Abundance Indices (SAIs) at multiple temporal and spatial scales using time series of vessel-based and remote sensing observations of Sargassum, and compared these SAIs to estimates of gray triggerfish recruitment. Our deliverables are intended to assist with the management of fisheries resources, and we will provide deliverables as needed to relevant on-going (e.g., greater amberjack count) and planned (e.g., Gulf of Mexico gray triggerfish SEDAR) assessments. We also developed and made available maps of frontal locations in the Gulf of Mexico, which help understand distributions of Sargassum and other ecologically important organisms. Our deliverables have also informed management of protected species (sea turtles) and has the potential to inform coastal communities dealing with Sargassum beaching events.

Products, Datasets, and Reports

Historical Sargassum maps at weekly and daily scales have been made available through USF’s Sargassum Watch System (SaWS)
Hugi, A. 2022. Trophic ecology of sailfish larvae in the Gulf of Mexico: an analysis of diet, prey availability, prey quality, and influences on larval growth. MS Thesis, University of Southern Mississippi. https://aquila.usm.edu/masters_theses/891
Lestrade, O. 2020. Microplastic abundance, distribution and impacts on Sargassum-associated juvenile fishes in the Gulf of Mexico. MS Thesis, University of Southern Mississippi. https://aquila.usm.edu/masters_theses/781
Lestrade, O., and F. Hernandez. 2021. NOAA RESTORE Science Program: linking habitat to recruitment: evaluating the importance of pelagic sargassum to fisheries management in the Gulf of Mexico: microplastic concentration and ingestion in the Northern Gulf of Mexico, 2017-07-20 to 2019-06-04 (NCEI Accession 0232040). NOAA National Centers for Environmental Information. Dataset.
Louisiana Universities Marine Consortium. 2022. Point Sur 1804, Gulfport, Mississippi, 2017-07-20 to 2017-07-28. Rolling Deck to Repository. Dataset.
Louisiana Universities Marine Consortium. 2022. Point Sur 1826, Gulfport, Mississippi, 2018-05-30 to 2018-06-06. Rolling Deck to Repository. Dataset.
Louisiana Universities Marine Consortium. 2020. Point Sur 1903, Gulfport, Mississippi, 2018-07-08 to 2018-07-17. Rolling Deck to Repository. Dataset.
Louisiana Universities Marine Consortium. 2020. Point Sur 1922, Gulfport, Mississippi, 2019-05-28 to 2019-06-05. Rolling Deck to Repository. Dataset.
Stachowiak, C. 2020. Assessing the nursery-role function of pelagic Sargassum for juvenile fishes in the northern Gulf of Mexico. MS Thesis, University of Southern Mississippi. https://aquila.usm.edu/masters_theses/786
Temperature and ocean color data products (e.g., chlorophyll concentration) at daily and weekly scales for the Gulf of Mexico have been made available through USF’s Virtual Antenna System
Wang, M. 2018. Spatial and temporal distributions of pelagic Sargassum in the Intra-Americas Sea and Atlantic Ocean. PhD Dissertation, University of South Florida. https://digitalcommons.usf.edu/etd/7716
Wang, M., C. Hu, and B. Barnes. 2019. Sargassum density and coverage using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data from 2001-01-01 to 2018-12-31 (NCEI Accession 0190272). NOAA National Centers for Environmental Information. Dataset.
Zhang, Y., and C. Hu. 2021. Data from: Ocean temperature and color frontal zones in the Gulf of Mexico: Where, when, and why. Mendeley Data. Dataset.

Peer Reviewed Publications

Hardy, R. F., Hu, C., Witherington, B., Lapointe, B., Meylan, A., Peebles, E., … & Hirama, S. (2018). Characterizing a sea turtle developmental habitat using Landsat observations of surface-pelagic drift communities in the eastern Gulf of Mexico. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 11(10): 3646-3659.

Hu, C., Wang, M., Lapointe, B.E., Brewton, R.A. and Hernandez, F.J., 2021. On the Atlantic pelagic Sargassum’s role in carbon fixation and sequestration. Science of The Total Environment, 781, p.146801. https://doi.org/10.1016/j.scitotenv.2021.146801

Lapointe, B.E., Brewton, R.A., Herren, L.W., Wang, M., Hu, C., McGillicuddy, D.J., Lindell, S., Hernandez, F.J. and Morton, P.L., 2021. Nutrient content and stoichiometry of pelagic Sargassum reflects increasing nitrogen availability in the Atlantic Basin. Nature communications, 12(1), pp.1-10.https://doi.org/10.1038/s41467-021-23135-7

Putman, N.F. and Hu, C. (2022). Sinking Sargassum. Geophysical Research Letters, 49, e2022GL100189. https://doi.org/10.1029/2022GL100189

Roberts, K.E., Garrison, L.P., Ortega-Ortiz, J., Hu, C., Zhang, Y., Sasso, C.R., Lamont, M., and Hart, K.M. (2022). The influence of satellite-derived environmental and oceanographic parameters on marine turtle time at surface in the Gulf of Mexico. Remote Sensing, 14, 4534. https://doi.org/10.3390/rs14184534

Shadle, S., O. Lestrade, F. Elmer and F. Hernandez Jr. (2019). Estimation and Comparison of Epiphyte Loading on Holopelagic Sargassum fluitans Collected in the North Atlantic Ocean and the Gulf of Mexico. Gulf and Caribbean Research 30(1): SC42-SC46

Trinanes, J., Putman, N. F., Goni, G., Hu, C., & Wang, M. (2021). Monitoring pelagic Sargassum inundation potential for coastal communities. Journal of Operational Oceanography, 1-12.

Wang, M. and Hu, C. (2020). Automatic extraction of Sargassum features from sentinel-2 msi images. IEEE Transactions on Geoscience and Remote Sensing, 59(3), 2579-2597.

Wang, M., & Hu, C. (2021). Satellite remote sensing of pelagic Sargassum macroalgae: The power of high resolution and deep learning. Remote Sensing of Environment, 264, 112631. https://doi.org/10.1016/j.rse.2021.112631

Wang, M., Hu, C., Barnes, B., Mitchum, G., Lapointe, B., and Montoya, J. (2019). The great Atlantic sargassum belt. Science. 365:83-87, 10.1126/science.aaw7912

Wang, M., Hu. C., Cannizzaro, J., English, D., Han, X.X., Naar, D., Lapointe, B., Brewton, R. and Hernandez, F. (2018). Remote sensing of Sargassum biomass, nutrients, and pigments. Geophysical Research Letters. 45(22):12359-12367, 10.1029/2018GL078858

Zhang, Y., & Hu, C. (2021). Ocean temperature and color frontal zones in the Gulf of Mexico: Where, when, and why. Journal of Geophysical Research: Oceans, 126(10), e2021JC017544. https://doi.org/10.1029/2021JC017544

News & Features

Tracking seaweed blooms with the Sargassam Watch System, Secoora, October 19, 2022
Mojaban belt appears around the same time in the Atlantic Ocean and Jeju Island, YNA, August 23, 2022.
Sargassum, the brown tide that threatens the coasts of the Caribbean: is it here to stay?, El Pais, August 17, 2022.
Record amount of seaweed is choking shores in the Caribbean, AP, August 3, 2022.
‘Sargassum storm’: Stinky seasonal seaweed sets record in Brevard, and more is coming this way, Florida Today, July 5, 2022.
From seaweed to soil: South Florida beach town finds a solution to a stinky problem, Fox Weather, June 24, 2022.
Brown seaweed could hit record levels at US beaches, AccuWeather, June 7, 2022.
Millions of tons of sargassum blossoming in Atlantic. Cayman Compass, February 17, 2022.
Scientists can spot shrimp eggs from space, Hakai, February 10, 2022.
Scientists can spy shrimp eggs from space, Hakai, February 9, 2022.
Beseiged by seaweed, Caribbean scrambles to make use of the stuff, Reuters, September 29, 2021.
Can science solve the seaweed problem on Mexican beaches? National Geographic, August 23, 2021.
Seaweed raises a stink on Fla. beaches: ‘Just get away’, E&E News, August 13, 2021.
The seaweed bloom that covered an ocean, Isabelle Gerretsen, BBC, November 19, 2020.
Seaweed monster back, swallowing South Florida beaches, Miami Herald, August 3, 2020.
Remember the thick seaweed issue? When we get back to the beach, it may be there… in tons, USA Today, May 7, 2020.
Southeast Florida grapples with algae blooms, The Journal of Montreal, June 1, 2019.
Seaweed siege unusual during tourism season, Palm Beach Daily News, April 3, 2019.
Off-season onslaught of seaweed overruns South Florida beaches, Sun Sentinel, March 25, 2019.
This natural, but nasty, nuisance is lurking off Palm Beach County’s coast, The Palm Beach Post, January 22, 2019.
Seaweed growth could return in 2019, Daily Commercial, January 1, 2019.
The Sargassum Invasion, Marlin, June 6, 2018.
Why Florida beaches are covered in seaweed, Treehugger, June 21, 2018.
Mysterious masses of seaweed assault Caribbean islands, Science, June 11, 2018.
How much Sargassum is in the Gulf of Mexico? Are juvenile fish that live in Sargassum more likely to survive to adulthood? Follow Weedlines, the larval fish ecology lab’s cruise blog, as they gather new Sargassum samples to help answer these questions. The cruise set sail on May 30, 2018.

Environmental Compliance Documentation

Environmental Assessment for “Linking habitat to recruitment: Evaluating the importance of pelagic Sargassum to fisheries management in the Gulf of Mexico”

FONSI for “Linking habitat to recruitment: Evaluating the importance of pelagic Sargassum to fisheries management in the Gulf of Mexico”