2024-03-28T17:00:13Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/570422022-11-17T02:08:08Zhdl_2115_20070hdl_2115_157Growth and age composition of northern shrimp Pandalus eous estimated by multiple length frequency analysisYamaguchi, HiroshiGoto, YokoHoshino, NoboruMiyashita, KazushiNorthern shrimpPandalus eousLength frequency analysisAge and growthAge-length keyCatch-at-age485We examined growth of northern shrimp Pandalus eous in the Sea of Japan, off western Hokkaido, to improve estimations of catch-at-age for stock assessment. Multiple length frequency analysis based on length frequency data collected by a scientific research vessel was conducted to examine length-at-age in the shrimp population. Multi-normal distributions estimated using maximum likelihood indicated a good fit to length distributions. AIC values and regression analyses revealed annual growth variation and a decreasing trend in the length at several age classes in the shrimp population. We revised the method for estimating catch-at-age from the age-conversion table (ACT), which is a simple method for age determination, to age-length keys (ALK) calculated from the results of multiple length frequency analysis. Abundant year classes caught successively year after year could be more easily identified from the catch-at-age data computed using ALK than by using ACT. Our results suggested not only that the mean size of commercial landings fluctuated based on changes in age composition but also that a decrease in the length-at-age in the population influenced the consistent size decrease of commercial landings.北海道西部日本海海域におけるホッコクアカエビの成長と年齢別漁獲尾数を推定するため,調査船標本にもとづく甲長組成解析を行い,年齢別サイズを調べた。解析結果から,成長の年変動と年齢別サイズの減少傾向が認められた。年齢別漁獲尾数の推定方法を,従来の甲長-年齢変換テーブル(ACT)から,age-length key(ALK)による方法に改良した。また,近年の漁獲物の小型化は,年齢組成の変動だけではなく,年齢別サイズの減少の影響を受けていることを明らかにした。SpringerJournal Articleapplication/pdfhttp://hdl.handle.net/2115/57042https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/57042/1/Northern_shrimp.pdf0919-9268AA10993718Fisheries Science8046656782014-07enginfo:doi/10.1007/s12562-014-0758-2author