The sharp-nosed sand goby Favonigobius gymnauchen is one of the most dominant fish species around tidal flats and sandy beaches in Japan and plays an important role in the food web. To clarify the habitat utilization and secondary production of F. gymnauchen in these waters, we investigated the density, size compositions, feeding, and prey availability in sandy beaches, a muddy sand estuary, and a seagrass bed in Hiroshima Bay, central Seto Inland Sea, Japan. The density of F. gymnauchen was the highest in the estuarine habitat and the lowest in the sandy beaches. They mainly consumed copepods, gammarids, and polychaetes. The body sizes of F. gymnauchen were larger in the estuarine habitat than in the seagrass bed, although prey availability was higher in the seagrass bed than in the estuary. Secondary production of F. gymnauchen was the highest (> 1 g wet weight m⁻² year⁻¹) in the estuarine habitat. The growth rate in the estuarine habitat was estimated to be 0.2 mm d⁻¹. In a laboratory experiment in which fish were exposed to various salinity conditions and fed excess food, the feeding and growth of F. gymnauchen were not significantly different at salinities of 5, 15, and 30, and the maximum growth of juveniles at nearly 25 °C was estimated to be 0.2 mm d⁻¹. These results indicate that F. gymnauchen grows at nearly maximum rates in estuarine habitats despite their high density, thereby resulting in the high secondary production of this species.

尖鼻沙虎鱼Favonigobiusgymnauchen是日本潮滩和沙滩周围最主要的鱼类之一，在食物网中发挥着重要作用。为了阐明这些水域中F.gymnauchen的栖息地利用和二次生产，我们调查了濑户内海中部广岛湾的沙滩、泥沙河口和海草床的密度、大小组成、摄食和猎物可用性， 日本。F.gymnauchen的密度在河口生境中最高，在沙滩中最低。他们主要食用桡足类、伽马科动物和多毛类动物。F.gymnauchen的体型河口栖息地中的数量比海草床中的大，尽管海草床中的猎物可用性高于河口。F.gymnauchen 的二次生产在河口栖息地中最高（> 1 g 湿重 m ^-2 年^-1）。河口栖息地的增长率估计为0.2 mm d ^-1。在鱼类暴露于各种盐度条件并喂食过量食物的实验室实验中，在5、15和30的盐度下，F.gymnauchen的摄食和生长没有显着差异，而在接近25°的盐度下，幼鱼的最大生长C估计为0.2mm d ^-1。这些结果表明F.gymnauchen 尽管河口栖息地密度高，但在河口栖息地中几乎以最大速度生长，从而导致该物种的高二次生产。