Purse seine fishers widely use drifting Fish Aggregating Devices (dFADs) to attract and capture tropical tuna across the world’s oceans. While effective for fisheries, dFADs pose significant ecological risks, particularly through marine pollution and beaching. This study presents the first regional assessment of dFAD dispersal and beaching patterns as marine litter in the Gulf of Guinea, using GPS buoy track data from dFADs deployed by French purse seiners operating in the region between 2008 and 2014. Spatial analysis reveals substantial variability in drift trajectories, driven by differences in deployment density and regional ocean circulation. The highest beaching rates are observed in the northeastern Gulf of Guinea, likely influenced by the retroflection of the Guinea Current and low deployment density. A second beaching hotspot occurs in the northern Gulf of Guinea, potentially affected by the Guinea Current and the eastward movement of mesoscale eddies. Beached dFADs pose severe ecological threats, especially in the Ivorian-Ghanaian upwelling zone, where high concentrations particularly in the northeast and around Cape Three Points overlap with key spawning habitats. This increases the risk of habitat degradation and disruption of critical fish populations. These findings highlight the urgent need for improved management strategies to mitigate the environmental impacts of dFADs in the region.
References
[1]
Imzilen, T., Chassot, E., Barde, J., Demarcq, H., Maufroy, A., Roa-Pascuali, L., et al. (2019) Fish Aggregating Devices Drift Like Oceanographic Drifters in the Near-Surface Currents of the Atlantic and Indian Oceans. Progress in Oceanography, 171, 108-127. https://doi.org/10.1016/j.pocean.2018.11.007
[2]
Maufroy, A., Chassot, E., Joo, R. and Kaplan, D.M. (2015) Large-Scale Examination of Spatio-Temporal Patterns of Drifting Fish Aggregating Devices (dFADs) from Tropical Tuna Fisheries of the Indian and Atlantic Oceans. PLOS ONE, 10, e0128023. https://doi.org/10.1371/journal.pone.0128023
[3]
Scott, G.P. and Lopez, J. (2014) The Use of FADs in Tuna Fisheries. European Parliament. Policy Department B: Structural and Cohesion Policies: Fisheries IP/B/PECH/IC/2013-123. p. 70.
[4]
Chassot, E., Goujon, M., Maufroy, A., Cauquil, P., Fonteneau, A. and Gaertner, D. (2014) The Use of Artificial Fish Aggregating Devices by the French Tropical Tuna Purse Seine Fleet: Historical Perspective and Current Practice in the Indian Ocean. 16th Session of the Working Party on Tropical Tunas, Bali, 15-19 November 2014, 17. http://www.documentation.ird.fr/hor/fdi:010063284
[5]
Lopez, J., Moreno, G., Sancristobal, I. and Murua, J. (2014) Evolution and Current State of the Technology of Echo-Sounder Buoys Used by Spanish Tropical Tuna Purse Seiners in the Atlantic, Indian and Pacific Oceans. Fisheries Research, 155, 127-137. https://doi.org/10.1016/j.fishres.2014.02.033
[6]
Imzilen, T., Lett, C., Chassot, E. and Kaplan, D.M. (2021) Spatial Management Can Significantly Reduce dFAD Beachings in Indian and Atlantic Ocean Tropical Tuna Purse Seine Fisheries. Biological Conservation, 254, Article ID: 108939. https://doi.org/10.1016/j.biocon.2020.108939
[7]
Imzilen, T., Lett, C., Chassot, E., Maufroy, A., Goujon, M. and Kaplan, D.M. (2022) Recovery at Sea of Abandoned, Lost or Discarded Drifting Fish Aggregating Devices. Nature Sustainability, 5, 593-602. https://doi.org/10.1038/s41893-022-00883-y
[8]
Maufroy, A., Kaplan, D., Chassot, E. and Goujon, M. (2018) Drifting Fish Aggregating Devices (dFADs) Beaching in the Atlantic Ocean: An Estimate for the French Purse Seine Fleet (2007-2015). ICCAT Collective Volume of Scientific Papers, 74, 2219-2229.
[9]
Balderson, S.D. and Martin, L.E.C. (2015) Environmental Impacts and Causation of “Beached” Drifting Fish Aggregating Devices around Seychelles Islands: A Preliminary Report on Data Collected by Island Conservation Society. Indian Ocean Tuna Commission, Olhao, 7-11 September 2015, 15.
[10]
Stelfox, M.R., Hudgins, J.A., Ali, K. and Anderson, R.C. (2014) High Mortality of Olive Ridley Turtles (Lepidochelys olivacea) in Ghost Nets in the Central Indian Ocean. Indian Ocean Tuna Commission WPEB10-28.
[11]
Castro, J.J., Santiago, J.A. and Santana-Ortega, A.T. (2001) A General Theory on Fish Aggregation to Floating Objects: An Alternative to the Meeting Point Hypothesis. Reviews in Fish Biology and Fisheries, 11, 255-277. https://doi.org/10.1023/a:1020302414472
[12]
Murua, H., Zudaire, I., Tolotti, M., Murua, J., Capello, M., Basurko, O.C., et al. (2023) Lessons Learnt from the First Large-Scale Biodegradable FAD Research Experiment to Mitigate Drifting FADs Impacts on the Ecosystem. Marine Policy, 148, Article ID: 105394. https://doi.org/10.1016/j.marpol.2022.105394
[13]
Taylor, G.I. (1922) Diffusion by Continuous Movements. Proceedings of the London Mathematical Society, 2, 196-212. https://doi.org/10.1112/plms/s2-20.1.196
[14]
Amemou, H., Koné, V., Aman, A. and Lett, C. (2020) Assessment of a Lagrangian Model Using Trajectories of Oceanographic Drifters and Fishing Devices in the Tropical Atlantic Ocean. Progress in Oceanography, 188, Article ID: 102426. https://doi.org/10.1016/j.pocean.2020.102426
[15]
Imzilen, T., Kaplan, D.M., Barrier, N. and Lett, C. (2023) Simulations of Drifting Fish Aggregating Device (dFAD) Trajectories in the Atlantic and Indian Oceans. Fisheries Research, 264, Article ID: 106711. https://doi.org/10.1016/j.fishres.2023.106711
[16]
Mansui, J., Molcard, A. and Ourmières, Y. (2015) Modelling the Transport and Accumulation of Floating Marine Debris in the Mediterranean Basin. Marine Pollution Bulletin, 91, 249-257. https://doi.org/10.1016/j.marpolbul.2014.11.037
[17]
Frankemölle, P.F.V.W., Nooteboom, P.D., Scutt Phillips, J., Escalle, L., Nicol, S. and van Sebille, E. (2024) Assessing the Drift of Fish Aggregating Devices in the Tropical Pacific Ocean. Ocean Science, 20, 31-41. https://doi.org/10.5194/os-20-31-2024
[18]
Setälä, O., Fleming-Lehtinen, V. and Lehtiniemi, M. (2014) Ingestion and Transfer of Microplastics in the Planktonic Food Web. Environmental Pollution, 185, 77-83. https://doi.org/10.1016/j.envpol.2013.10.013
[19]
Escalle, L., Scutt Phillips, J., Brownjohn, M., Brouwer, S., Sen Gupta, A., Van Sebille, E., et al. (2019) Environmental versus Operational Drivers of Drifting FAD Beaching in the Western and Central Pacific Ocean. Scientific Reports, 9, Article No. 14005. https://doi.org/10.1038/s41598-019-50364-0
[20]
Scutt Phillips, J., Escalle, L., Pilling, G., Sen Gupta, A. and van Sebille, E. (2019) Regional Connectivity and Spatial Densities of Drifting Fish Aggregating Devices, Simulated from Fishing Events in the Western and Central Pacific Ocean. Environmental Research Communications, 1, Article ID: 055001. https://doi.org/10.1088/2515-7620/ab21e9
[21]
Bourles, B., Molinari, R.L., Johns, E., Wilson, W.D. and Leaman, K.D. (1999) Upper Layer Currents in the Western Tropical North Atlantic (1989-1991). Journal of Geophysical Research: Oceans, 104, 1361-1375. https://doi.org/10.1029/1998jc900025
[22]
Lumpkin, R. and Garzoli, S.L. (2005) Near-Surface Circulation in the Tropical Atlantic Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 52, 495-518. https://doi.org/10.1016/j.dsr.2004.09.001
[23]
Djakouré, S., Penven, P., Bourlès, B., Veitch, J. and Koné, V. (2014) Coastally Trapped Eddies in the North of the Gulf of Guinea. Journal of Geophysical Research: Oceans, 119, 6805-6819. https://doi.org/10.1002/2014jc010243
[24]
Bosson, K., Aman, A., Toualy, E. and Arnault, S. (2023) The Surface Guinea Current Variability from Satellite Data. Regional Studies in Marine Science, 64, Article ID: 103045. https://doi.org/10.1016/j.rsma.2023.103045
[25]
Herbert, G., Bourlès, B., Penven, P. and Grelet, J. (2016) New Insights on the Upper Layer Circulation North of the Gulf of Guinea. Journal of Geophysical Research: Oceans, 121, 6793-6815. https://doi.org/10.1002/2016jc011959
[26]
Koné, V., Lett, C., Penven, P., Bourlès, B. and Djakouré, S. (2017) A Biophysical Model of S. aurita Early Life History in the Northern Gulf of Guinea. Progress in Oceanography, 151, 83-96. https://doi.org/10.1016/j.pocean.2016.10.008
[27]
Amemou, H. (2021) Modélisation biophysique de la dispersion et de la croissance des larves de sardinelles dans le Golfe de Guinée. Sorbonne Université and Université Félix Houphouët-Boigny.
[28]
Amemou, H., Bosson, K. and Koné, M. (2025) Impact of Diel Vertical Migration (DVM) on Sardinella aurita Retention in the Northern Gulf of Guinea. Research in Marine Sciences, 10, 667-684.
