Phytoplankton and Aquaculture Sustainability
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Date
2026-06-30
Authors
MESSAOUI, Yousra
Journal Title
Journal ISSN
Volume Title
Publisher
ENSSMAL
Abstract
This study was conducted at the Ain Taya aquaculture site, in the coastal waters east of Algiers, over two seasonal field campaigns, in February and May 2026, with the objective of assessing the environmental influence of floating fish cages on the surrounding Aïn Taya coastal waters and phytoplankton community structure. Five sampling stations were established around the farm, and five parameters were measured: total suspended solids, dissolved inorganic nutrients (NO₃⁻, NO₂⁻, NH₄⁺, PO₄³⁻, SiO₄⁴⁻), chlorophyll-a concentration, phytoplankton taxonomic composition, and ecological diversity indices. Results show a measurable nitrogen enrichment gradient centered on ST01, the cage center, most pronounced in May when nitrate concentration reached 0.8097 µmol/L, indicating an early stage of eutrophication near the cage structures. The phytoplankton community was dominated by diatoms throughout both campaigns, with Skeletonema sp. reaching 45,640 cells L⁻¹ at ST01 in May. Diversity indices indicate a reduction
in biological diversity at nutrient-enriched stations, with a Simpson dominance index of D =0.789 at ST01 in May, reflecting near-monoculture bloom conditions. One potentially harmful species, Alexandrium sp., was detected at ST03 during May. Taken together, the results confirm that the Ain Taya aquaculture installation exerts a detectable but spatially limited environmental influence on the coastal waters of this southwestern Mediterranean site under current operating conditions