Abstract:Saccharina japonica is a major economically important brown macroalgae. It is an important primary producer in the marine ecosystem and is also cultured under long-line in coastal northern China. The aim of this work was to develop an individual growth model capable of simulating the growth of the large-scale raft-cultured kelp in the north of China. The model can provide data support, to some extent, to northern kelp farming. The key processes for kelp growth and its relationship with environmental parameters were analyzed, using the Sanggou Bay aquaculture zone as the study area. We used the visualization model software STELLA, which simulated and predicted the growth of the length and dry weight of kelp. The individual growth model basic framework was Ngrowth = Ggrowth–resp–Ekelp, where, net growth was defined as gross growth minus respiration and erosion consumption. The gross growth of kelp was defined as a function of light, temperature, salinity, and internal nutrient (N and P) content in kelp, whereas the light parameters were obtained from the Sanggou Bay meteorological records, and salinity, temperature, and nutrient (N and P) measurements were observed at the site in Sanggou Bay. According to the model simulated results, model predictions are well within the observed results. The individual growth model simulated the length results and measured values of the kelp, with the fitting degree R2 in the high, medium, and low zones as 0.936, whereas dry weight simulated results and measured values of the kelp had fitting degree R2 in the high, medium, and low zones as 0.963. According to the results, the model can accurately reflect the true growth process of kelp. A reliable individual growth model is the basis for the assessment of aquaculture carrying capacity. In addition, the individual growth model may provide a scientific foundation for aquaculture spatial planning and management.
