Species composition, distribution and proposal for protection of shrimp larvae – juveniles in Hai Phong – Quang Ninh coastal sea
Abstract
From 2015 to 2020, 85 sample vials, in total, of 5 ichthyoplankton surveys were carried out in the Hai Phong - Quang Ninh seas, including 3 surveys representing the Northeast and 2 others presenting for Southwest monsoon seasons. Initially, 34 species belonging to 15 families were identified, with 7 shrimp families dominating in quantity and frequency of occurrence, accounting for 98.39% of total shrimp larvae and juveniles obtained. The average density of shrimp-shrimp larvae reached 13,223±228 individuals/1000 m3 of seawater, in which the average density of the Southwest monsoon season reached 22,654±964 individuals/1000 m3, higher than that of the Northeast monsoon season 6,936±584 individuals/1000 m3; and there was a significant variation over time with P<0.05. In the Northeast monsoon seasons, breeding areas of shrimp were in the coastal zones of Ha Long Bay to Cat Ba Island down to the southwest coast of Hai Phong bordering Thai Binh. In the southwest monsoon season, the distribution density tends to shift away from the shore, concentrating in the area of Tran island, the sea southeast of Hon Dau, the area between the northeast of the Long Chau archipelago up to the South of Ha Mai Island and Ngoc Vung Island. These areas could be considered to set up the forbidden or limited exploitation during spawning seasons and planning serves for fishery resource management.
