@article{oai:oacis.repo.nii.ac.jp:00002451,
 author = {田中, 栄次},
 issue = {1},
 journal = {日本水産学会誌, Nippon Suisan Gakkaishi},
 month = {Jan},
 note = {サバ類太平洋系群のVPAの推定値とカタクチイワシ太平洋系群の年齢別漁獲尾数，親魚量の推定値を用い，チューニングVPAでサバ類によるカタクチイワシの捕食死亡率を推定した。自然死亡係数をサバ類の資源量の線形式で表し，推定期間中の平均値が使用されていた経験値と一致するように調節した。年間の捕食死亡率は1995年の0.06（95%CI: 0.03-0.09）から2018年の0.43（0.28-0.54）に増加したと推定された。, Virtual population analysis (VPA) was applied to data of the Pacific stock of the Japanese anchovy Engraulis japonicus in order to estimate its annual rate of predation mortality by the Pacific stocks of chub mackerel Scomber japonicus and spotted mackerel Scomber australasicus. 
Data used in this analysis were catch-at-age and absolute abundance estimates by egg production survey for the anchovy stock from 1995 to 2018, and existing biomass es timates of the two stocks of mackerel. The natural mortality coefficient of the anchovy stock is assumed to be a linear function of the sum of biomass of the mackerel stocks. 
Unknown parameters are estimated by maximizing log-likelihood using the abundance estimates and theoretical ones by VPA with the constraint that the mean of natural mortality coefficients over the years is equal to the empirical value of the coefficient used in past studies. 
The results showed that estimates of the annual rate of predation mortality increased from 0.06 (per year, 95%CI: 0.03-0.09) in 1995 to 0.43 (0.28-0.54) in 2018. Appropriateness of the estimates and future data collection for in corporating predation into models of natural mortality were discussed.},
 pages = {2--11},
 title = {サバ類資源によるカタクチイワシ太平洋系群の捕食死亡率の推定},
 volume = {88},
 year = {2022}
}