Resource-limited Gracilaria dura partitions resources between growth and survival: Knowledge base for optimizing production

Gracilaria dura is commercially important due to its agarose quality. Thus, production in aquaculture is increasing. Maximizing its yield requires mastering its life cycle. The distinct generations and stages of its isomorphic biphasic life cycle have been observed to diverge their biomechanical properties and eco-physiological responses. Functional traits such as growth, regeneration, pigments, antioxidant capacity, and productivity related to growth and survival can explain the differences observed among stages and/or among sites. We tested for differences in several functional traits among life stages (female gametophyte and tetrasporophyte) of G. dura originated from two locations (Adri and Veraval) along the Indian coast and grown in an open sea farm. A Principal Component Analysis (PCA) showed associations among pigments, antioxidant activity, and productivity. In the largest association, pigments R-PE and R-PC were negatively correlated with productivity (NPP and GPP). In the second-largest association, pigments R-PC and R-PE were negatively correlated to antioxidant capacity (CUPRAC and TAC). These results indicate that G. dura in the Indian Ocean is resource-limited and must partition its use of resources between traits that promote growth and traits that promote survival. Both ploidy phases, collected from different locations, when cultivated in the same environment, showed similar eco-physiological responses. This suggests that G. dura populations from each of these locations are genetically and phenotypically similar, and thus equally suited for optimized farming.