فهرست نشریات علمی دسترسی آزاد ایران

BACKGROUND AND OBJECTIVES: Seasonal variability represents a critical environmental driver influencing seaweed growth and heavy metal accumulation in coastal aquaculture systems. Variations in rainfall intensity, salinity regimes, and water circulation patterns may alter environmental stability and pollutant dynamics, thereby affecting both production performance and product safety. Despite its importance, comprehensive information regarding the combined effects of seasonal conditions on biomass development and lead contamination in cultivated Gracilaria verrucosa remains limited, particularly in tropical pond ecosystems. The study objectives were to examine the effects of dry and wet seasons on growth characteristics, production yield, and lead accumulation in pond cultivated G. verrucosa in the coastal area of Ujungpangkah, Gresik, Indonesia.METHODS: Field observations and sample collection were conducted during the dry season from April to September 2024 and the wet season from October 2024 to March 2025. Sixty samples were obtained in each season. Growth performance indicators, including absolute biomass, growth rate, and production yield, were determined using standardized cultivation evaluation methods. Lead concentrations in seaweed tissues were quantified through laboratory based chemical analyses. Seasonal differences were assessed using independent statistical tests to identify significant variations between sampling periods.FINDINGS: The results demonstrated clear seasonal contrasts in biomass production and lead accumulation, both of which were markedly higher during the dry season. Mean absolute biomass in the dry period (128.33 ± 60.41 grams) was more than twofold that recorded in the wet season (55.83 ± 20.54 grams; P = 0.021). Likewise, lead concentrations were significantly elevated under dry conditions (4.57 ± 0.79 milligrams per kilogram) compared with the wet season (2.99 ± 0.58 milligrams per kilogram; P = 0.006). In contrast, neither specific growth rate nor agar yield differed significantly between seasons (P > 0.05), suggesting that fundamental physiological efficiency remained relatively consistent throughout the annual cycle. CONCLUSION: The findings confirm that seasonal variation plays a decisive role in regulating biomass production and lead accumulation in Gracilaria verrucosa culture systems. Although the dry season supports higher productivity, it simultaneously elevates contamination risk. Consequently, the implementation of seasonally adaptive management practices, continuous environmental monitoring, and strengthened pollution control measures is essential to ensure sustainable production and food safety in coastal seaweed aquaculture.