In 2022, the Fisheries Research Institute under the Council of Agriculture was commissioned by the Penghu County Government to conduct a dynamic investigation of silver anchovy resources in Penghu Waters. During the underwater investigation conducted in Chihkan territorial waters in Paisha Township, Penghu County, the spawning of silver anchovy was the first video recorded at a depth of 15 meters in the North Sea of Penghu. The investigation results can provide Taiwan’s government with the opportunity to adjust existing management regulations and promote the sustainable use of resources.
According to the Fisheries Research Institute, Spratelloides gracilis, commonly known as silver anchovy, is a type of small, mesopelagic fish that is an important economic food fish in Taiwan. More than 99% of Taiwan's catch comes from Penghu County. Although the Penghu County Government has established a closed season for silver anchovy from May 1 to June 1 each year since 1999, the annual fishery statistics report shows that the catch of silver anchovy shows a yearly downward trend in recent years. To address this issue, the Penghu County Government commissioned Kuo-Wei Lan, an associate professor at National Taiwan Ocean University, and the Fisheries Research Institute to conduct a joint investigation. The study collected statistical data on the development of mature fish gonads, track recorders, and fishing logs, and found that the Chihkan territorial waters in Paisha Township, Penghu County are one of its spawning grounds. Associate professor Lan and the Fisheries Research Institute’s research team found that the reproductive period of silver anchovy ranges from March to September, and peaks between April and May and between July and August.
In order to further confirm the spawning and habitat substrate of silver anchovy, researchers from the Fisheries Research Institute conducted an underwater investigation in Chihkan territorial waters in Paisha Town, Penghu County of Taiwan at the end of June 2022. They found that a school of silver anchovy showed inconsistent and irregular rapid swimming at a depth of 15 m, as well as small schools of fish chasing each other. The schools of fish scurried and touched the bottom of the sea with their bodies, and the originally clear water was smoky due to male fish discharging semen. Silver anchovy is characterized by swimming in groups, and generally, their swimming is quite uniform and rhythmical. The above findings conform to foreign recordings of herring spawning, hence, the observation of researchers from the Fisheries Research Institute can be confirmed as the spawning of silver anchovy.
The Fisheries Research Institute indicated that this investigation was the first time that the spawning of silver anchovy had been video recorded in Taiwan, and in the future, it will continue the investigation to accurately grasp the scope of the spawning grounds. Silver anchovy has a short life cycle. If the correlation between environmental factors in spawning grounds and the reproduction peak periods can be established, spawning can be accurately predicted based on the key impact factors in combination with hydrological and technological information. According to the current regulations, the fishing ban can be adjusted or extended year by year, or protected areas can be established based on spawning grounds, which will more effectively protect pregnant fish and hatched juvenile fish, and the goal of sustainable resource utilization can be achieved.