An idea for marine ranching planning based on ocean currents and its practice in Zhongjieshan Archipelago National Marine Ranching, China

Marine ranching in China are becoming integrated systems with multiple function zones after decades of development. Meanwhile, stock enhancement has always been an important component of marine ranching in China. However, although all marine ranching in China are located in energetic coastal seas, few studies have considered ocean currents during the spatial layout planning of function zones and the temporal planning of stock enhancement in marine ranching. Therefore, marine ranching planning based on ocean currents was proposed, which not only requires function zones located along ocean current pathways to increase nutrient transfer efficiency between function zones but also requires stock enhancement to avoid strong circulation which could carry fishes far from release sites. Guided by the above idea, the current pattern around Zhongjieshan Archipelago National Marine Ranching (ZANMR), China, was depicted, and planning suggestions were made on the basis of the current results. The results revealed that periodic tidal currents and quasisteady circulation were dominant around ZANMR. Since the spatial scale of the tidal excursion was comparable to the size of ZANMR, the tidal current pathways could serve as fast nutrient transport paths from the artificial-reef core function zone to the extension function zones. Therefore, southwest of Miaozihu (MZH) Island and northwest of Xifushan (XFS) Island could be the locations for future extension function zones. The circulation around ZANMR presented significant seasonal variations and was very strong during autumn and winter. Therefore, stock enhancement in ZANMR should be implemented during spring and summer when circulation is weak. The successful practice of marine ranching planning on the basis of ocean currents in ZANMR implies broader applications to analogous marine ranching. •An idea for marine ranching planning based on ocean currents was proposed.•The core and extension function zones in marine ranching were argued to locate along currents paths.•Stock enhancement in marine ranching was argued to avoid strong circulations.