Growth rate comparison of three Kappaphycus alvarezii colour strains cultivated using tubular netting and tie-tie methods in the waters of Ecuador

Abstract Kappaphycus alvarezii is widely cultivated in tropical regions, with its growth influenced by cultivation techniques. Despite extensive global studies, there is a knowledge gap in Ecuador regarding the performance of different strains and systems under local specific conditions. The growth performance of K. alvarezii strains (green, brown, and red) cultivated in Ecuador using “tubular nets” and “tie-tie systems” was evaluated. Fifteen thalli from each strain were grown for 70 days, with daily measurements of water temperature, salinity, dissolved oxygen, turbidity, and nutrient levels. No significant differences were detected between the systems, and their DGR growth rates were high for algae culture development (4.0 ± 0.92% day⁻1 in the tie-tie and 3.8 ± 0.81% day⁻1 in the tubular net) demonstrating their suitability for commercial cultivation. All strains exhibited DGR > 3%, with the green strain particularly excelling in the tubular system (6.1 ± 5.54% day⁻1). The local environmental conditions were found to be favourable for macroalgal growth, with a particularly strong positive correlation with temperature. The results show that both cultivation systems are viable for the commercial production of K. alvarezii, establishing a foundation for future applications in local aquaculture and highlighting the adaptability of the evaluated strains to Ecuador's environmental conditions.