桑沟湾海带标准化养殖模式的优势探析

针对桑沟湾养殖海区海带(Laminaria japonica)的超容量养殖现象，研究了该海区中标准化养殖模式和传统养殖模式的海带生长差异。结果显示，在标准化养殖模式下，海带长、宽、平均厚度、湿重、投影面积和特定生长率均高于传统养殖模式，单棵海带重量显著提高，且海带的碳、氮和蛋白质含量明显高于传统养殖模式，海带品质大大提升。养殖后期，标准化养殖海区养殖海带垂直投影面积之和与对应养殖海区面积之比为6.33，而传统养殖模式的比值为9.15；标准化养殖海区海带所处水层下方的光照强度显著高于传统养殖区，海带所处水层的海流流速也高于传统养殖区。研究表明，桑沟湾海带标准化养殖模式使海带养殖密度降低，海带生长速度和品质均得以提高；在标准化养殖模式下，海带重叠较小，接受的光照比传统养殖模式充足；较快的海流使标准化养殖海区营养盐更新速度更快，这两方面可能是导致2种养殖模式下海带生长和品质产生差异的原因。

Analysis on the Advantages of Standard Kelp Long Line Culture in Sanggou Bay

In the 1990s, kelp (Laminaria japonica) aquaculture was over capacity in Sanggou Bay; however, the area used for kelp aquaculture has almost doubled since then. Consequently, the levels and proportion of nutrients has changed since the end of last century. In order to address this problem, we previously established standard long line culture to reduce kelp density. After two years, profit had increased significantly; however, the reasons why kelp growth improved in the standard long line culture area compared to the traditional area remained unknown. This study was carried out to elucidate the advantages of standard kelp long line culture in Sanggou Bay. There were two 40 hm2 experimental areas: a standard kelp long line culture area and a traditional long line culture area. The distance between the two areas was approximately 50 m. The growth and composition of kelp, light density, and current in both areas were measured throughout the experiment. The length, width, average thickness, wet weight, projected area, and specific growth rate of kelp were higher in the standard long line culture area than in the traditional long line culture area, with kelp weight significantly higher in the standard area. The carbon, nitrogen, and protein content of the kelp in the standard long line culture area was significantly higher than that in the traditional culture area, and the quality of the kelp product was greatly improved. During the later stages of cultivation, the ratio of the sum of the projection area of cultured kelp in the standard culture area to the corresponding cultured sea area was 6.33, while that of the traditional area was 9.15. The light density of the water layer beneath the kelp in the standard area was significantly higher than that in the traditional area, and the current speed was also higher in the standard area than in the traditional culture area. Our results showed that kelp overlap decreased in the standard area and that total light density was higher in the standard area than in the traditional area. Moreover, the increased current in the standard area carried more nutrients to the kelp. These may be the factors resulting in differences between the two methods of kelp culture.