Impact of Transportation Duration on the Growth, Pathological Stress, and Dry Biomass Yield of Kappaphycus striatus Propagules

Seaweed cultivation is a primary economic driver in Tawi-Tawi, Philippines, yet the industry faces significant challenges regarding the physiological integrity of propagules during inter-island transit. This study evaluated the effects of varying transportation durations (0, 12, 24, 36, and 48 h) on the specific growth rate (SGR), occurrence of ice-ice disease, and dry biomass yield of Kappaphycus striatus over a 30-day cultivation period using a modified fixed-off-bottom method. The results demonstrated that transportation duration significantly influenced SGR at Day 10 and Day 30 (p < 0.05), whereas no significant differences were observed at Day 20. The control group (0 h transport) exhibited the highest growth performance (4.61 ± 0.18% day−1 at Day 10), whereas the lowest growth was recorded in the 48 h treatment group at Day 30 (0.93 ± 0.49% day−1). Pathological assessment indicated that ice-ice disease occurrence was highly significant during the initial recovery phase (Days 1–7) and at Day 20 (p < 0.05). Specifically, propagules subjected to 48 h transport reached 100% disease incidence within the first four days post-transplant, while the 36 h group reached 96.67%, highlighting acute transport-induced stress. Although the 48 h group exhibited significantly higher initial ice-ice spot counts (p < 0.05), statistical differences diminished between Day 10 and Day 30, suggesting a degree of physiological resilience and recovery capacity. Ultimately, prolonged transportation exceeding 24 h induced severe dehydration stress, resulting in a 62.7% reduction in SGR by Day 30 compared to the control. These findings suggest that seedling transport should be optimized within a 24 h window to preserve thallus vigor and maximize sustainable yields. Future research should investigate post-transport recovery protocols to mitigate the effects of unavoidable shipping delays.