This research aimed to reduce reliance on chemical antifouling agents; it was conducted at depths of 0.5 and 1.5 meters in the Eastern Harbor, at Alexandria, Mediterranean Sea. This study delves into the realm of environmentally sustainable antifouling solutions by exploring the efficacy of natural crude extracts from two Red Sea sponge species, Acanthella acuta (Extract A) and Carteriospongia sp. (Extract B).
The results revealed a rich diversity of fouling organisms, encompassing six phyla, seven classes, eleven orders, twenty-two families, and thirty-three species. Noteworthy absences were noted at specific depths, indicating depth-dependent variations in fouling communities. The application of extract A at 0.5 meters depth demonstrated significant reductions in fouling biomass and shifts in dominant species. Treatment 3 stood out with the lowest biomass (9.69 ± 2.83 g/m²) and the fewest species (only 2 species). At 1.5 meters depth, extract B exhibited consistent trends with treatment 6 displaying the lowest biomass (20.85 ± 23.35 g/m²) and also species diversity (only 2 species). Meanwhile, Extract B showcased compelling antifouling potential. At 0.5 meters depth, treatment 4 exhibited notable reductions in fouling biomass, dominated by Balanus amphitrite, Balanus eburneus, and Balanus sp. At 1.5 meters depth, treatment 6 emerged as the most effective, with the lowest biomass (249.3 ± 120.4 g/m²) and a streamlined species composition.
This study underscores the promise of natural crude extracts from the Red Sea sponges as potent alternatives for environmentally friendly antifouling strategies. The observed variations in fouling biomass and species composition offer critical insights for the development and application of these extracts in combating fouling organisms, presenting a significant stride toward sustainable marine ecosystem conservation.