HYDROBIOLOGIST, POLAR EXPLORER, FIRST DIRECTOR OF IO RAS P.P. SHIRSHOV

This article is a short scientific and biographical sketch about petr petrovich shirshov (12/25/1905, Dnepropetrovsk – 02/17/1953, Moscow) – hydrologist, polar explorer, Doctor of Geographical Sciences (1937), Academician of the USSR Academy of Sciences (1939), Hero of the Soviet Union (1938 ), the first director of the institute of oceanology of the russian academy of sciences (1946 – early 1953). The Institute bears the name of P.P. Shirshov. Of course, in the year of the anniversary, all of us – employees of the Institute of Oceanology – remember with gratitude and respect the name of Petr Petrovich – the largest scientist-researcher, hydrobiologist, organizer of science and an amazing, deep, very courageous, gifted person with a bright and difficult fate. The article presented below is especially valuable because it pays close attention to the work of P.P. Shirshov as a hydrobiologist. His contribution to history as the organizer of the Institute of Oceanology or a polar explorer is widely sanctified in various publications, but his scientific hydrobiological research is much less known, meanwhile it was this direction that interested Petr Shirshov as a scientist more than anything else.

Identification guide to larvae of Caucasian Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae)

The Caucasus and adjacent areas are inhabited by fifteen species of mayflies of the genus Epeorus, subgenus Caucasiron Kluge, 1997 (Heptageniidae). This identification guide aims to facilitate an accurate species identification of their larvae and sum up all available information on their taxonomy and distribution. An identification key is provided, and the important diagnostic characters of all species are described and illustrated. The larva of E. (C.) insularis (Braasch, 1983) is described for the first time. This study enables the routine identification of Caucasiron larvae necessary for biomonitoring and hydrobiological research in the Caucasus region.

On finding of Monocorophium insidiosum Crawford, 1937 (Amphipoda, Corophiidae) in the coastal waters of Crimea (Black Sea), a new species for this region

An illustrated description of morphology of Monocorophium insidiosum Crawford, 1937 from the Crimean coastal waters is given. In this work, 744 specimens from different locations and substrates of the Crimean coastal waters have been analyzed. The main specific parameters of species from the Crimean coastal waters are as follows: rostrum of males is about one half of first article of antenna I length, dactylus of gnathopod II is equipped with 2–4 additional spines along the inner side (both for males and females). Variability is observed in parameters of the following parts: first article of antenna I peduncle, fourth article of antenna II peduncle, inner side of gnathopod II dactylus, and outer sides of the outer and inner rami of uropod II. Morphological parameters of specimens from the Black Sea, the Mediterranean Sea (literature data), and the North America coast (Vancouver area, literature data) have been compared. Specimens from the Black Sea are morphologically similar, but have some differences from the North American ones. In particular, first article of antenna I peduncle of specimens from the North America have conical process (specimens from the Black Sea have rounded process); fifth article of antenna II peduncle is with proximal medial tooth (specimens from the Black Sea are without proximal medial tooth); and outer ramus of uropod II has medial spine (Mediterranean specimens are without such a spine). These differences should be taken into account when carrying out hydrobiological research.

SPLITTING OF TROPHIC NICHES IN UNDERYEARLINGS OF MINNOW PHOXINUS PHOXINUS (L.) AND GUDGEON GOBIO GOBIO (L.) SHARING THE SAME HABITAT

The article gives the results of determining feeding spectra of underyearlings of minnow ( Phoxinus phoxinus (L.)) and gudgeon ( Gobio gobio (L.)) living in the middle flow of the river Kes’ma (tributary of Rybinsk reservoir), as well as limits of feeding biotopes of their juveniles and proportion of structural zones determining their ecological niches at the first year of life. Analysis of similarity and distinction of food composition consumed by fry of both fish species utilizing common foraging resources in the process of sharing the same habitat was performed. It was shown that diet of gudgeon fry is more diverse, compared to minnow fry. Gudgeon was found to forage on invertebrates belonging to seven classes while minnow’s diet comprised representatives of four classes. Food objects common for both fish species were oligochaetes and larvae of amphibiotic insects. Chironomid larvae dominated in the food of both fish species. This can be observed in both the frequency of occurrence of these food items in the digestive tract (100%), as well as in the indices of its mass in the boluses. Species composition of chironomid larvae found in the food of gudgeon and minnow was significantly different. These differences are conditioned by both the biological features of single species such as their confinement to certain micro-habitats as well as the foraging behavior of fish fry. Because of current lack of hydrobiological research in the Kes’ma river, the prelist of invertebrates found in dietary intake of fish fry of the local habitat is considered to have a great practical value.