Annual Report of the U.S. Atlantic Salmon Assessment Committee Report No. 30-2017 Activities

Total returns to USA rivers was 1,041; this is the sum of documented returns to traps and returns estimated by redd counts. This, year ranks 20 out of 27 years for the 1991-2017 time series. Documented returns to traps totaled 972 and returns estimated by redd counts was 69 adult salmon. Most returns were to the Gulf of Maine Distinct Population Segment, which includes the Penobscot River, Kennebec River and Eastern Maine coastal rivers, accounting for 96.8% of the total returns. Overall, 34.9% of the adult returns to the USA were 1SW salmon, 63.7% were 2SW salmon and 1.2% were 3SW or repeat spawners. Most (77.4 %) returns were of hatchery smolt origin and the balance (22.6%) originated from either natural reproduction, 0+ fall stocked parr, hatchery fry, or eggs. A total of 4,262,454 juvenile salmon (eggs, fry, parr, and smolt), and 4,849 adults were stocked into US rivers. Of those fish, 265,528 carried a mark and/or tag. Eggs for USA hatchery programs were taken from 310 sea-run females and 1,678 captive/domestic and domestic females. Total egg take (8,213,649) was much higher than the previous three years’ average of 6,302,893, partially due to the increased numbers of spawners used (previous three-year average of 1,641 females). Production of farmed salmon in Maine was not available, due to regulations concerning privacy. 2018 NMFS (National Marine Fisheries Service) NEFSC (Northeast Fisheries Science Center) Submitted https://doi.org/10.25923/1r4s-5r39 Public Domain 1930

美国河流中的鲑鱼回归总量为1041尾，该数值为陷阱捕获的已记录回归个体数与通过产卵场计数（redd counts）估算的回归个体数之和。在1991-2017年的时间序列中，该年份的回归总量位列第20位（共27个统计年份）。通过陷阱捕获的已记录回归成年鲑鱼总计972尾，通过产卵场计数（redd counts）估算的回归个体为69尾。绝大多数回归个体分布于缅因湾独特种群单元（Gulf of Maine Distinct Population Segment），该单元涵盖佩诺布斯科特河、肯纳贝克河以及缅因州东部沿海河流，其回归个体占总量的96.8%。整体而言，美国境内回归的成年鲑鱼中，34.9%为单游程鲑鱼（1SW salmon），63.7%为双游程鲑鱼（2SW salmon），剩余1.2%为三游程鲑鱼（3SW salmon）或重复产卵个体。77.4%的回归个体为孵化场培育的幼鲑（hatchery smolt）来源，剩余22.6%则来自自然繁殖、当年秋季放流的0龄稚鲑（0+ fall stocked parr）、孵化场仔鱼（hatchery fry）或鱼卵。美国河流中共累计放流幼鲑阶段个体（含鱼卵、仔鱼、稚鲑及幼鲑）4262454尾，以及成年鲑鱼4849尾。其中265528尾个体被施加了标记或标签。美国孵化场项目所用的鱼卵取自310尾洄游产卵雌性个体以及1678尾圈养/驯化雌性个体。累计采卵总量达8213649枚，远高于前三年平均水平（6302893枚），这一差异部分源于本次所用产卵亲体数量的增加（前三年平均亲体数量为1641尾雌性个体）。由于隐私相关法规限制，缅因州的养殖鲑鱼产量数据无法获取。本数据集由美国国家海洋渔业局（NMFS, National Marine Fisheries Service）下属的东北渔业科学中心（NEFSC, Northeast Fisheries Science Center）于2018年提交，DOI为https://doi.org/10.25923/1r4s-5r39，属于公有领域（Public Domain），相关标注年份为1930。