The results of the Laboratory of Nonlinear Dynamical Systems (2022)

According to voting at the Institute Scientific Council, the following result was recognized as the most important one in the Institute in 2022 and was included in the list of the most important results of the Earth Science Department of the Russian Academy of Sciences

«Water masses favorable for living and catching pollock in the Sea of Okhotsk: calculation, Lagrangian and statistical analyses, recommendations for fishermen»  

In order to find places favorable for living and catching pollock, the most massive fishery object in the Far East of Russia, a new diagnostics are proposed based on Lagrangian maps of the origin and «age» of waters calculated daily from satellite data. Using daily data on the position of vessels in the fishing seasons in the Sea of Okhotsk in 1997 - 2021 and statistical analysis, it is shown that pollock fishing grounds are mainly located in the «young» waters of the Pacific origin, which enter the sea through the northern Kuril straits within 100 days before the dates of the catches. It is shown that pollock fishing locations are concentrated in intrusions and on the Lagrangian fronts of the Pacific water, which are warmer and richer in food. Lagrangian maps are calculated in real time in any weather and can be transferred on board of fishing vessels by e-mail for prompt operative forecasting of potential fishing grounds. As to the water ‘age’, the statistically significant difference according to the Kolmogorov-Smirnov sample test, D=0.2555 at a significance level p<2.2·10^-16 (Fig.1b), was found between samples with true pollock fishing grounds and randomly distributed points. As to the latitude of penetration of Pacific water into the sea for randomly selected virtual Lagrangian particles (rose) and particles in pollock fishing grounds we found D=0.60818, p<2.2·10^-16 (Fig.1c). It is much smaller than the machine zero.

 

Fig.1. a) An example of the maps of origin and «age» of Pacific water (shown in color) that entered the Sea of Okhotsk from the ocean through the Kuril Straits. Yellow and green – «young» Pacific waters. Red circles - positions of vessels in the fishery in the period 3 days before and 3 days after the indicated date; b) Cumulative functions of the distribution of the travel time of the Pacific water from the Kuril Straits to the true (green curve) and randomly distributed (red curve) pollock fishing areas with averaging in 1997 – 2021; c) Distribution functions of the probability of penetration of Pacific water into the sea over latitudes along the section along the Kuril Straits for randomly selected virtual Lagrangian particles (rose) and particles in pollock fishing grounds (gray).

S.V. Prants. Marine life at Lagrangian fronts // Progress in Oceanography. 2022. V.204. 102790. 10.1016/j.pocean.2022.102790 (the 1^st quartile JCR)

M.V. Budyansky, V.V. Kulik, K.K. Kivva, M.Yu. Uleysky, and S.V. Prants. Lagrangian Analysis of Pacific Waters in the Sea of Okhotsk Based on Satellite Data in Application to the Alaska Pollock Fishery. Izvestiya, Atmospheric and Oceanic Physics, 2022, Vol. 58, No. 12, pp. 1427–1437. DOI: 10.1134/S0001433822120088