POD! Fish- DFG Sturgeon Population estimates and fishery information

Purpose/Objective: Understand white sturgeon and green sturgeon population dynamics. Determine how abundance, distribution, and mortality rates of adult sturgeon are affected by water development and the sport fishery. If sturgeon populations are negatively impacted by changes in freshwater outflow and water export associated with water development, develop criteria to reduce the impacts. If the sport fishery causes unacceptably high mortality on the populations, address through changes in angling regulations. ACTIVITIES: Abundance estimates are made using tag and recapture methods. Sturgeon are tagged and released in San Pablo Bay during fall. Each tagged fish is measured. A year-round creel census is conducted to learn the tagged to untagged ratio and to determine the size composition of catch. Tag returns (corrected for non-response using reward tags) are used to estimate annual harvest rates, mortality rates and migrations.

研究目的：阐明白鲟（white sturgeon）与绿鲟（green sturgeon）的种群动态特征，探明水体开发与休闲渔业对鲟鱼成鱼的种群数量、分布范围及死亡率的影响机制。若鲟鱼种群因水体开发相关的淡水径流量变化与跨区域水资源调运受到负面影响，则制定相应标准以减轻此类影响；若休闲渔业对种群造成难以接受的高死亡率，则通过调整垂钓法规予以应对。
研究活动：采用标记重捕法（tag and recapture）开展种群数量估算。秋季于圣巴勃罗湾（San Pablo Bay）对鲟鱼进行标记并放流，同时测量每尾标记个体的体长。开展全年渔获普查，以掌握标记个体与未标记个体的比例，并确定渔获物的体长组成。利用经奖励标记法（reward tags）校正无回复偏差后的标记回捕数据，估算年度捕捞率、死亡率及洄游情况。