Zoologičeskij žurnal

Nine new species of the genus Oligaphorura are described based on material from various parts of the Russian Federation. Among them, three species, O. ossetica sp. n., O. anocellata sp. n., and O. octosetosa sp. n., are representatives of the Caucasian fauna. The former one belongs to the marcuzzii-group and differs from other members of the group by an increased number of dorsal and subcoxal pseudocelli. Oligaphorura anocellata sp. n., from the differens-group, shows the same pattern of dorsal pseudocelli as O. hackeri (Christian), but it lacks subcoxal pseudocelli. The latter Caucasian species described here, O. octosetosa sp. n. (the daii-group), is characterized by the presence of eight distal setae on the tibiotarsi, four papillae in the antennal organ, and only one pair of pseudocelli on the second thoracic tergum. Oligaphorura ligni sp. n., from the absoloni-group, is from the southern Primorye, Russian Far East, and it can be distinguished from the probably most similar, Chinese species O. shifangensis Liu et Sun by a longer unguiculus, a smaller postantennal organ, and fewer ventral parapseudocelli. The remaining five species described belong to the groenlandica-group and were found in different parts of the eastern Palaearctic. Oligaphorura yakutica sp. n. is most similar to O. duocellata Babenko et Fjellberg, from the Magadan Region, due to the presence of two pairs of dorsal pseudocelli on the first thoracic segment and a peculiar furcal remnant. Yet it is easily distinguishable from the latter by the complete absence of pseudocelli on the abdominal sterna. Oligaphorura subnuda sp. n., from the Taimyr Peninsula, northern Siberia, differs from the Nearctic O. nuda (Fjellberg) by the presence of pseudocelli on the fourth abdominal sternum. Oligaphorura cavicola sp. n., a species found in a cave in the northern Urals, is characterized by an increased number of dorsal pseudocelli on all abdominal segments (44454) and, unlike such sympatric congeners with the same number of abdominal pseudocelli as O. interrupta (Fjellberg) or O. nuda (Fjellberg), it shows a pseudocellus each side of the thorax I. Oligaphorura neglecta sp. n., widespread in the NE Palaearctic, is very similar to the circumpolar O. groenlandica (Tullberg). These two species can be distinguished by the presence/absence of a cuticular fold in the furcal remnant and different lengths of axial setae on the fifth abdominal terga. Finally, O. primorica sp. n., from the Russian Far East, can be compared to several Korean species described by Weiner (1994). All of them have a unique type of granulation that covers the anterior part of the body and the last abdominal segment, probably representing an isolated regional group of related species. The new species is characterized by the same number of pseudocelli as O. koreana (Weiner) and differs from the latter species (and the other related congeners of the region) in having strongly differentiated dorsal setae. An updated key to all presently known 77 Oligaphorura species is also given.

The specificity of utilizing the frequency of occurrence indicator in relation to the study of the species structure of a fish community is considered. The coastal ichthyocenosis of the Baltic Sea within the Kaliningrad Region was used as a study object. Fishing was carried out at up to 20 m depths using a set of collection of gillnets with a mesh size of 12 to 80 mm in the period 2006–2022. In total, data on 894 catches were summarized, in which 11.8 thousand fish were caught. It is shown that the frequency of occurrence of a species can be presented in several ways: (1) as the average for the catches of the entire set of mesh, (2) as the maximum for the mesh size optimal for a given species, (3) as a structural characteristic that determines the nature of an ichthyocenosis’ species organization. In general, in the catches of a collection of gill nets the coastal ichthyocenosis was found to be represented by 29 species of fish, among which the river flounder, Baltic herring, round goby and smelt dominate in terms of occurrence. In the interannual aspect, the occurrence rate is demonstrated to show certain stability and is characterized by a confidence interval ranging within ±10–20%. Taking into account that the indicator of occurrence is quite simply determined just through the capture record of a species, it is recommended to use it in addition to the traditional indicators of the relative abundance and biomass of the species. Using multi-cell fishing gear for the assessment of the structure of a fish community is prerequisite.

Based on the results of long-term observations, the colonization of the islands of the Murmansk coast, Barents Sea by northern gannets (Morus bassanus (L. 1758)) is described. The formation of colonies on the Murman Islands is shown to be associated with the restoration of the stocks of juvenile Atlantic herring in the Barents Sea in the 1990’s to the 2000’s along with an intense influx of birds from the Norwegian part of the species’ range. The population dynamics of the species in two Russian colonies are also analyzed. The end of the previous and the beginning of this decade were marked by an abrupt increase in population numbers in both Russian colonies. To date, the general distribution area of this species includes the southern part of the Barents Sea and the entire water area of the White Sea; the eastern border of its nesting distribution area being restricted to Kharlov Island, eastern Murman in the Barents Sea. Starting with 2022, the population dynamics in the westernmost Russian colony have been determined by mortality caused by the HPAIV avian influenza epidemic, this threatening further development of both Russian colonies. In the summer of 2023, using the phenotypic indicator of the previous infection, the number of sick birds in the colony was determined as amounting to 13–15% of the total number of individuals nesting there.

In the central Sikhote-Alin Mountains, tigers prey mainly on underyearlings and adult female wild boars (67–74% of the total number of this species’ prey). In key plots (≥10–15 km²) in the Sikhote-Alin Nature Reserve, (a) wild boar encounters and their tracks in the network of routes were recorded; (b) wild boar snow tracking was performed; and (c) tiger encounters and snow tracking were registered (114 episodes). We obtained 16 movement patterns of wild boar groups using snow tracking. Snow tracking of each wild boar group took 6 to 23 days. Many maternal groups occupied a position central in relation to other accompanying groups (up to 8) and individuals (up to 15) moving in the vicinity, usually over an area (1.5–9.4 km² or more) that was 1.1–2.2 or more times larger than the area of the maternal group under normal conditions. Such a dynamic organization of associations that serves as a kind of pre-adaptation to the probable appearance of a predator revealed the effectiveness against the tiger both randomly searching for prey and tracking it along a trail. The number of tiger attacks on accompanying wild boars temporarily separated from the parental group was nearly three times (p < 0.05) as high as the number of attacks by the predator on maternal groups in key plots. In the relationships between the predator and prey species, (a) the location of the habitats of the maternal wild boar groups matters as well, in snowy winters also of compact camps, all usually at a distance from regular tiger routes; (b) disturbed wild boars broadened the search areas, at tiger pursuits and attacks they also changed the site; (c) the tuskers, the male wild boars that accompany maternal groups, often “disguise” these groups by moving to the side of the most probable tiger appearance.