Changes in the biomass of necton and macroplankton during the day (day/night) during the period of pre-airfield migrations of pacific salmon in the northwestern Pacific Ocean in 2004–2020

• Published in: Izvestiya TINRO
• Main Author: P. G. Milovankin
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Transactions of the Pacific Research Institute of Fisheries and Oceanography 2022
• Subjects: сзто; верхняя эпипелагиаль; суточная динамика; нектон; макропланктон; Aquaculture. Fisheries. Angling; SH1-691; Keta; Pacific; Oncorhynchus gorbuscha
• Online Access: https://doi.org/10.26428/losos_bull16-2022-79-87; https://doaj.org/article/8c44e0b6136646e1a4288339556ff8e4

This article discusses changes in the biomass of taxa of trawl macrofauna during the day in the upper epipelagial of the northwestern Pacific Ocean. Information from the database «Marine Biology» No. 0220006765 in the state register was used, flights to the NIS «Professor Kaganovsky», NIS «Professor Levanidov» and NIS «TINRO» during the pre-airfield migrations of Pacific salmon in May-July 2004–2020 in the amount of 1,471 trawls in the water area of more than 1 million km2 . It has been established that the period of years 2004–2013 is the «pre-sardine epoch», and since 2014 — the next «sardine epoch». The average water surface temperature was higher in the «pre-sardine epoch» than in the «sardine epoch» 7.2 oC versus 7.1 oC. At night (19-07 hours), the average number of taxons in the catch increases, the Simpson index and average body sizes decrease. Only 5 out of 140 taxa do not change their specific biomass during the day: Aequorea sp., Chrysaora melanaster, Oncorhynchus gorbuscha, O. keta и Phacellophora camtschatica. The following 16 taxa are never found in daytime catches: Benthalbella dentata, Ceratoscopelus warmingii, Diaphus theta, Icichthys lockingtoni, Lipolagus ochotensis, Notoscopelus japonicus, Tarletonbeania crenularis, Trachipterus ishikawae, Lampanyctus jordani, Desmodema lorum, Nemichthys scolopaceus, Stenobrachius leucopsarus, Symbolophorus californiensis, Arctozenus risso, Leuroglossus schmidti, Chiroteuthis calyx.