Cook Inlet Belugas, Delphinapterus leucas: Status and Overview

Of the five populations of beluga, Delphinapterus leucas, in Alaska, the most isolated is the one in Cook Inlet (Hazard, 1988; Hill and DeMaster, 1998) (Fig. 1). The geographic and genetic segregation of this stock (O’Corry-Crowe et al., 1997), combined with the beluga’s tendency toward site fidelity in summer, makes this population especially vulnerable to impacts from large or persistent harvests.

Occurrence of the Macrocyclops distinctus (Richard) (Copepoda, cyclopoidida) in Rybinsk reservoir. [Translation of: Materialy po biologii i gidrologii Volzhskikh Vodokhranilishch. Moscow, Leningrad 1963, pp. 13-16]

This brief chapter describes the occurrence Macrocyclops distinctus in the littoral zone of the Rybinsk Reservoir. Sampling was undertaken in summer and autumn 1961. In order to facilitate distinction of M. distinctus and Macrocyclops fuscus the author presents drawings of the whole species and certain characteristic parts of the body, and also gives a description of M. distinctus, comparing it with M. fuscus.

Observations on the behaviour of Polyphemus pediculus and functions of its extremities in the process of feeding. [Translation of: Materialy po biologii i gidrologii Volzhskikh vodokhranilishch, pp. 13-16. Moscow, 1965]

The author summarises observations on the behaviour of Polyphemus pediculus and functions of its extremities in the process of feeding. The crustacean Polyphemus pediculus seizes its prey, kills it and pulverises its food with the help of its extremities. Therefore for a study of its feeding method was necessary not only to have been acquainted in detail with the structure of its extremities, but also to have observed their interaction for the accomplishment of the stated functions.

The state of the benthos in the Rybinsk reservoir, 1953-55. [Translation of the abstract from: Trudy biol. Sta. Borok 3, 195-213, 1958]

This abstract summarises the 1953-1955 surveys of the distribution of benthos in the Rybinsk Reservoirs. It includes the mean biomass of benthos.

Megacylops viridis Jurine, abyssal form in Lake Maggiore. [Translation of: Memorie dell'Istituto Italiano di Idrobiologia Dott.Marco de Marchi 17 57-79, 1964]

Megacyclops viridis Jurine, noticed in Lago Maggiore in 1912 by De Marchi from the littoral vegetation of Pallanza, is a normal member of the littoral plankton of the lake. The subgenus Megacyclops, created by Kiefer in his revision of the viridis-vernalis group, contains european and american species some of which are today considered as varieties of the species viridis. This paper examines morphology and of the distribution of the Italian viridis in Lake Maggiore.

Mastigophora and Rhizopoda found in saline lakes Weissovo and Repnoie (near Slaviansk). Selected passages describing Ochromonas species and Pedinella. [Translation of: Trudy Obshch.Ispyt.Prir.imp.khar'kov.Univ. 21 119-140, 1888]

This translation includes selected passages of a longer paper on Mastigophora and Rhizopoda found in saline lakes Weissovo and Repnoie. The translation focuses on describing taxonomy and morphology of Ochromonas species and Pedinella. Plates and figures of the original paper are not included in the translation.

Discovery of viruses lysing blue-green algae in the Dneprovsk reservoirs. [Translation of: Water blooms (ed. A. V. Topachevskii) pp.171-174. Kiev, Naukova Dumka, 1968]

Viruses, which are characterised by a relative simplicity of chemical composition, are involved with all the groups of the animal and plant world. The discovery of viruses of lower organisms has special interest. Along with the already known viruses lysing bacteria and actinomycetes, viruses have been discovered in recent years which lyse algae. During investigations of water from water-bloom patches and of mud taken from zones of massive accumulation of blue-green algae in the Dneprovsk reservoirs, the authors obtained viruses lysing algae. The revealing of viruses producing lysis of blue-green algae, which one could use in the control of water-blooms, has the greatest interest. With this aim, samples of water were collected from various zones of water-bloom patches in the Kremenchug, Dneprovsk and Kukhov reservoirs. For viruses lysing algae we propose the name 'algophages'. Along with the existence of viruses of algae of the phage type, one cannot deny the possibility of the existence of viruses of another type, multiplying in the cells of algae and causing their virus illnesses.

On the population dynamics of Eudiaptomus gracilis Sars and Heterocope borealis Fischer in the Bodensee-Obersee. Part B. Eudiaptomus gracilis Sars. [Translation from: Trudy Instituta Biologii Vnutrennykh Vodnany 12(15) 170-174, 1966.]

Experimental research was conducted to study the development of eggs of Eudiaptomus gracilis Sars. The egg production was studied as well as the population dynamics. Factors like losses in the lake and through the effluent Rhine at Konstanz were considered.

The presence in the Marche of Sericostoma siculum McL. (Insecta-Trichoptera). Translation from: Boll.Soc.eustachiana 43(2), 47-50, 1950]

The caddisfly (Trichoptera) Sericostoma siculum was found in the Marche region in Italy. The article summarises biology and ecology of the caddisfly, focusing on the larvae stage.

On a method of determination of chlorophyll in cells of algae collected on a membrane filter. [Translation from: Trudy Instituta Biologii Vnutrennykh Vodnany 11(14), 198-202, 1966.]

The original method, proposed by Yentsch (1957), of determination of chlorophyll directly in the cells, attracts attention by its simplicity. In order to measure the content of chlorophyll by this method, a determined volume of suspension of algae is filtered through a membrane filter. The latter is dried a little, clarified by immersion oil, clamped between two glasses, and spectrophotometrized. Extinction is read off at , wavelengths equal to 670 millimicrons (around the maximum absorption of chlorophyll a in the cell) and 750 millimicrons (correction for non- specific absorption and dispersion of light by particles of the preparation). The method of Yentsch was employed by the authors for determination of chlorophyll-a in samples of phytoplankton. They conclude that in spite of the simplicity and convenience of determination the method must be applied sufficiently carefully. It is more suitable for analysis of cultures of algae, where, non-specific absorption of light is insignificant.

On the methods of determining size/weight characteristics of food organisms of fish. (Determination of the length of Copepoda in larval stages by egg-laying females of the free living freshwater Copepoda). [Translation from: Voprosy Ikhtiologii 14, 182-194, 1960. ]

As is known, copepods play an important role in the nutrition of fish. Therefore with a view to facilitating research on the study of the quantitative side of feeding, there have recently appeared a considerable number of papers devoted to the development of methods for determining the wet. weight of these crustaceans. For the further facilitating of research in the nutrition of fish it would be of great interest to clarify the problem, is there not some kind of rule in the growth of the crustaceans during metamorphosis, and if there is such a rule is it not possible, to determine the length of the larvae at each stage, not by measuring them, but by using the formulae derived on the basis of these rules. This article examines the growth curves of different species of freshwater Copepoda, obtained on the basis of experimental observations in cultures or by way of measurement of mass material at all stages of development in samples from water-bodies. The authors study in particular the ratio of the mean diameter of the eggs to the mean length of the egg-bearing females.

Tests of some specific effect substances in duck nutrition. Translation from: Biologisace a chemisaze vyzivy svirat 5, 43-48, 1969.]

There is a constantly increasing collection of manufactured substances, whose effectiveness in the sustenance of ducks is under investigation. The author examines the effects of some substances already previously tested and also there were examined substances which had not hitherto been studied. The use of different supplements for late autumn fattening is studied through various experiments.

The possibilities and dangers in using malachite green in pisciculture.[Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod No.3 17-21, 1969.]

For many years a dye has been used in the practise of pisciculture and pond management, which is known by the name of malachite green, and is used to combat fungus on fish, fish eggs and external animal parasites on fish. The authors describe the problem of the application of malachite green in pisciculture and undertake special, complementary research.

Rhythms of division of some algae in situ and in laboratory culture. [Translation from: Studii Cerc.Biol.(Bot.) 21, 61-65, 1969. ]

The rhythm of division of 9 species belonging to different groups of algae were analysed in situ and in the laboratory. The research which developed in different environmental conditions attempted to establish the capacity for multiplication and assimilation of chlorophyll on the part of the algae under study with a view to placing them in a culture. The results obtained showed that the green multicellular algae (eg. Ulothrix) and the blue algae (eg. Lyngbya, Oscillatoria) are able to produce an appreciable quantity of dry matter, just as the unicellular algae. At the same time it arises that amongst the numerous factors of the environment, temperature plays one of the most important roles in the process of multiplication.

Investigations on the vertical migration of planktonic Crustacea in the Bodensee-Obersee. [Translation from: Schriften des Vereins fur Geschichte des Bodensees und seiner Umgebung, 87, 177-187, 1969.]

The vertical zoning of the planktonic Crustacea in a lake is the expression of a complex set of different factors. Besides the measurable, external influences such as light, temperature, acid and C02 stratification, a particularly large part is played by internal factors, which co-ordinate a specific reaction in each species depending on state of development, age and sex. Supporting this extensive, predictable, annual course of diurnal depths and the daily vertical migrations, whose extent is again dependent on external conditions, primarily of course on the amount of light. The individual factors mentioned, however, are here also of great significance. Within the scope of a long-term study of the planktonic Copepoda of Lake Constance, some day and night series were in 1963 also carried out in the Obersee, in order to obtain at least volumetric data on the extent of the daily migrations of these creatures.