A new species of the genus Coryphella(Gastropoda: Nudibranchia) from the Kuril Islands

A new species of the family Coryphellidae, Coryphella alexanderi sp. nov. is described based on specimens collected in the Kuril Islands, NorthWest Pacific, from the upper sublittoral to 200 m depth. An integrative analysis was conducted, including a molecular phylogenetic analysis based on four markers (COI, 16S, H3, 28S), an automatic species delimitation method ABGD, and an analysis of the external and internal morphology using light and scanning electron microcopy. The distinctiveness of Coryphella alexanderi sp. nov. is well established both morphologically and genetically, and it differs from externally similar species in radular characters. Phylogenetically Coryphella alexanderi sp. nov. is closely related to Coryphella trophina, which occurs sympatrically in the same geographic and bathymetric ranges. Coryphella alexanderi sp. nov. appears to be restricted to the middle and northern Kuril Islands, which is consistent with the high numbers of endemic taxa in this area.

Walleye pollock (Gadus chalcogrammus, Pallas, 1814) fishery, size and age composition, state of stocks and catch prospects in the waters adjacent to Kamchatka peninsula and Northern Kuril Islands

The article provides data on the catch of the Northern Okhotsk, Eastern Kamchatka and Western Bering Sea walleye pollock stocks, fishery structure by the fishing gears in 2016–2019, size and age composition of the fish in the commercial trawl and Danish seine catches in 2010–2019. Data on the generation abundance and stock condition indices used in the stock assessment models are also demonstrated. Interannual dynamics of the total and spawning stock biomass, determinants of the dynamics and prospects of fishing are analyzed.

The 2019 Eruption Dynamics and Morphology at Ebeko Volcano Monitored by geophysical instrument networks and Unoccupied Aircraft Systems (UAS)

<p>Vulcanian explosions are hazardous and are often spontaneous and direct observations are therefore challenging. Ebeko is an active volcano on Paramushir Island, northern Kuril Islands, showing characteristic Vulcanian-type activity. In 2019, we started a comprehensive survey using a combination of geophysical field station records and repeated unoccupied aircraft system (UAS) surveys to describe the geomorphological features of the edifice and its evolution during ongoing activity. Seismic data revealed the activity of the volcano and were complemented by monitoring cameras, showing a mean explosion interval of 34 min. Digital terrain data generated from UAS quadcopter photographs allowed for the identification of the dimensions of the craters, a structural architecture and the tephra deposition at cm-scale resolution. The UAS was equipped with a thermal camera, which in combination with the terrain data, allowed it to identify fumaroles, volcano-tectonic structures and vents and generate a catalog of 282 thermal spots. The data provide details on a nested crater complex, aligned NNE-SSW, erupting on the northern rim of the former North Crater. Our catalog of thermal spots also follows a similar alignment on the edifice-scale and is also affected by topography on a local scale. New analysis are included in this presentation as well as a long term change analysis based on remote sensing data.</p>

PACIFIC COD OF THE KURIL ISLANDS: STOCK AND CONTEMPORARY FISHING

The paper analyzes the long-term dynamics of stocks and annual catches of Pacific cod of the Kuril Islands, and also considers the structure of its modern fishery, taking into account the changes that have occurred in the organization of its coastal fishing in recent years. It was shown that the dynamics of commercial biomass of Pacific cod in the Northern and Southern Kuril Islands is comparable to that in 1975-2020 for groups in the southeastern part of the Bering Sea, the Karagin and Olyutor bays, on the shelf of Western Kamchatka, and in south-western Sakhalin. Development of the cod fishery in the North and South Kuril Islands in 1980-2019 went in accordance with the dynamics of stocks, the maximum catches were observed during the period of a high level of abundance of both groups in the 1980s. While the structure of the cod fishery on the shelf of the Northern Kuril Islands to date can be considered established, the development of fishing in the South Kuril Islands in the last two decades went by the gradual replacement of trawl fishing in the winter-spring period with snorkeling in the summer season.

The 2019 Eruption Dynamics and Morphology at Ebeko Volcano Monitored by Unoccupied Aircraft Systems (UAS) and Field Stations

Vulcanian explosions are hazardous and are often spontaneous and direct observations are therefore challenging. Ebeko is an active volcano on Paramushir Island, northern Kuril Islands, showing characteristic Vulcanian-type activity. In 2019, we started a comprehensive survey using a combination of field station records and repeated unoccupied aircraft system (UAS) surveys to describe the geomorphological features of the edifice and its evolution during ongoing activity. Seismic data revealed the activity of the volcano and were complemented by monitoring cameras, showing a mean explosion interval of 34 min. Digital terrain data generated from UAS quadcopter photographs allowed for the identification of the dimensions of the craters, a structural architecture and the tephra deposition at cm-scale resolution. The UAS was equipped with a thermal camera, which in combination with the terrain data, allowed it to identify fumaroles, volcano-tectonic structures and vents and generate a catalog of 282 thermal spots. The data provide details on a nested crater complex, aligned NNE-SSW, erupting on the northern rim of the former North Crater. Our catalog of thermal spots also follows a similar alignment on the edifice-scale and is also affected by topography on a local scale. This paper provides rare observations at Ebeko volcano and shows details on its Vulcanian eruption style, highlighting the relevance of structural and morphologic control for the geometry of craters and tephra fallout as well as for structurally controlled geothermal activity.