Ryazanova T.V.,Kamchatka Research Institute of Fisheries and Oceanography |
Eliseikina M.G.,RAS A.V. Zhirmunsky Institute of Marine Biology
Russian Journal of Marine Biology | Year: 2010
Diseases caused by microsporidia were found in the red king crab Paralithodes camtschaticus and the blue king crab P. platypus that inhabit the Sea of Okhotsk. Based on the histological features of the invasion and data on the morphological structure of the parasites, the microsporidia were assigned to the genera Thelohania and Ameson. Infected crabs exhibited severe destructive changes of their internal organs along with sharply pronounced external signs of disease. During the observation period, the microsporidian invasion was only found in females and young (unmarketable size) males from August to mid-October. Later, until mid-December, no diseased crabs were found. © 2010 Pleiades Publishing, Ltd.
Lepskaya E.V.,Kamchatka Research Institute of Fisheries and Oceanography |
Jewson D.H.,University of Ulster |
Usoltseva M.V.,Russian Academy of Sciences
Diatom Research | Year: 2010
Kurilskoye Lake is a deep (max. depth 316 m), oligotrophic lake that has been affected by nearby volcanic eruptions and extensive fertilisation aimed at increasing primary productivity in order to support a sockeye salmon fishery. Aulacoseira subarctica has dominated the phytoplankton community since studies began in 1980. Maximum cell concentrations were relatively low (from 137 cells ml -1 in 1987 to 3,710 cells ml -1 in 1990) and, in most years, occurred between June and August. More intensive seasonal studies were started in 2000 and these showed that there was little or no net diatom cell increase in some years. Even when an increase did occur, it could take up to two months for the population to double, mainly because of limited light availability resulting from deep mixing. Phosphorus was the main limiting nutrient but silica concentrations were relatively low and limited diatom growth in one out of 19 years. Further phosphate increases are likely to cause more extensive silica limitation and a probable shift in phytoplankton community composition. The lake did not freeze every year but when it was ice covered for over 100 days A. subarctica did less well. Comparison with other A. subarctica populations showed that cell dimensions were similar but that the frequency of auxosporulation was low.
Stepanov V.G.,Russian Academy of Sciences |
Morozov T.B.,Kamchatka Research Institute of Fisheries and Oceanography
Russian Journal of Marine Biology | Year: 2014
Two species of holothurians of the order Molpadiida were found on the shelf of Kamchatka and the Kurile Islands: Molpadia orientalis (Saveljeva, 1933) comb. nov. and M. roretzi (von Marenzeller, 1877). Molpadiid holothurians were not previously recorded in waters near Kamchatka and the Kurile Islands. Brief descriptions of the morphology of the two species, distribution and ecology data, as well as figures depicting calcareous rings and body skin ossicles, are provided. © 2014 Pleiades Publishing, Ltd.
Zavolokin A.V.,Pacific Research Fisheries Center |
Kulik V.V.,Pacific Research Fisheries Center |
Zavarina L.O.,Kamchatka Research Institute of Fisheries and Oceanography
Russian Journal of Marine Biology | Year: 2014
Based on the data of 28 surveys that were carried out by the Pacific Fisheries Research Center in the Sea of Okhotsk, Bering Sea, and Pacific waters during 2001-2010, we analyzed the interannual variability of indirect indices of the food supply of the Pacific salmon (Oncorhynchus): the daily food ration, daily consumption rate, diel feeding chronology, diet overlap, trophic niche breadth, number of prey items, and the share of minor food. The years of the most pronounced changes in the diet composition and consumption rate of Pacific salmon were revealed. The variability of different trophic characteristics as indicators of the salmon food supply is discussed. Despite a significant increase in salmon abundance in the 2000s compared to previous years, no marked changes occurred in their feeding spectra and consumption rates. © 2014 Pleiades Publishing, Ltd.
Afanasyev P.K.,Russian Federal Research Institute of Fisheries and Oceanography |
Orlov A.M.,Russian Federal Research Institute of Fisheries and Oceanography |
Novikov R.N.,Kamchatka Research Institute of Fisheries and Oceanography
Journal of Ichthyology | Year: 2014
According to materials of trap, long-line, and trawl fishing, specific features of distribution of sablefish Anoplopoma fimbria and some of its biological characteristics in Pacific waters off the southeastern coast of Kamchatka, continental slope of the western part of the Bering Sea, Shirshov Underwater Ridge, and off the Commander Islands are considered. Maximum density concentrations according to data of trap fishing was noted along southeastern coast of Kamchatka and the data of trawl fishing indicated most frequent catches in the western part of the Bering Sea in the area of Koryak coast up to Cape Navarin. The pattern of vertical distribution in different areas considerably differs. The magnitude of trap catches in different areas is different and determined by the type of trap and the period of soaking. The size composition, fatness, and the sex ratio are different in catches of different fishing gear and differ between regions. On the whole, in Russian Far Eastern waters, females mature in mass at a body length of 71 cm and males at 57 cm. © 2014 Pleiades Publishing, Ltd.