http://10.0.0.195:8080/dspace/handle/11099/891 Thu, 09 Feb 2012 04:05:49 GMT 2012-02-09T04:05:49Z http://10.0.0.195:8080/dspace/handle/11099/1207 Title: Методика и результаты учета численности молоди речной камбалы (Platichthys flesus) и тюрбо (Scophthalmus maximus) в восточной Балтике в 1986 и 1987 гг. Authors: Витиньш, М. Я. Abstract: A total of 106 exploratory catches taken in June and September 1986 and 1987 at 5 fishing stations throughout the Latvian coast were aimed at further perfection of recruitment predictions for the flounder commercial stock. Altogether 3773 0-group, 1- and 2-year-old flounders and 128 turbot fingerlings have been examined. A method of the survey has been described. It has been found that the June surveys of 1-year-old fish are the most reliable. In September one may get the first preliminary estimate of the 0-group abundance. The main young fish concentration areas have been noted. The 1985 year-class of flounder was estimated to be average, the 1986 - abundant, and the 1987 year-class of poor abundance. The low water temperatures of 1987 caused the low growth rate of young fish and, perhaps, poor survival of larvae. The share of 1-year-old and 0-group turbot in the beach seine catches constituted 3 and up to 20 % of the same group flounder number respectively. Sun, 01 Jan 1989 00:00:00 GMT http://10.0.0.195:8080/dspace/handle/11099/1207 1989-01-01T00:00:00Z http://10.0.0.195:8080/dspace/handle/11099/1202 Title: Некоторые аспекты питания личинок балтийских рыб Authors: Грауман, Г. Б.; Лисивненко, Л. Н.; Сидревиц, Л. Л. Abstract: Comparisons have been made between the food compositions and feeding peculiarities of larval sprat, cod, flounder, hake, sand eel, and sand goby of a length of 4 to 22 mm in spring and summer. According to the body shape, structure of alimentary tract, size of mouth opening, and feeding and movement patterns, the larvae fall into 2 groups: the I group larvae (sprat, sand eel) differ from those of the II group by a stretched body, narrow alimentary tract, small mouth opening, and they are less mobile. The II group larvae are smaller when they begin to feed upon large food items, and percentage of feeding individuals in this group is higher than in the I. Food diversity of sprat is low, and this species is highly sensitive to the food deficiency. Feeding intensity differ between the seasons. The food spectrum of fishes is wider in July than in May and June. The food-selective indices have been calculated for larval fish. Sun, 01 Jan 1989 00:00:00 GMT http://10.0.0.195:8080/dspace/handle/11099/1202 1989-01-01T00:00:00Z http://10.0.0.195:8080/dspace/handle/11099/1206 Title: О нагульных миграциях шпрота в подрайонах ИКЕС 26 и 28 Балтийского моря Authors: Швецов, Ф. Г.; Градалев, Е. Б. Abstract: Using the data of hydroacoustic surveys in May and September 1985 - 1987 the schemes of distribution were obtained for the spawning (May) and feeding (September) sprat. The quantitative analysis of sprat seasonal distribution and of the dynamics of hydrological conditions for these years enabled to define peculiarities of horizontal feeding migrations of fishes in Sd 26 and 28. It has been established that sprat of old and average age groups migrate meridionally along the deep-water part of the Gotland Deep and the direction vector of these migrations depends upon the dynamics of the warm surface layer. In the years when the residual stock predominate over recruiting one, the young age groups of the former migrate to the coastal zone and begin to feed in the shallow sea areas. In the years of high recruitment abundance migration pattern is vice versa. The fish of young age groups actively migrate both, longitudinally and latitudinal. Sun, 01 Jan 1989 00:00:00 GMT http://10.0.0.195:8080/dspace/handle/11099/1206 1989-01-01T00:00:00Z http://10.0.0.195:8080/dspace/handle/11099/1205 Title: Пополнение, динамика запаса и промысел шпрота в северной Балтике в 1950-1987 гг. Authors: Апс, Р. А.; Бененсон, И. Е.; Маханек, А. О.; Калейс, М. В. Abstract: Using the long-term data, the dependence has been derived for sprat stock recruitment size in the northern Baltic upon the salinity, water temperature, and the spawning stock size. It has been established that the long-term variations in the Northern Baltic sprat stock are little fishery-dependent, but are controlled by the abundant periodically occuring yearclasses. The fishery strategies optimization can't effect significantly the general dynamics of sprat abundance. The appearance of abundant year-classes depends upon abiotic conditions for eggs development, e.i. upon the vertical distribution of salinity and temperature above the halocline. Sun, 01 Jan 1989 00:00:00 GMT http://10.0.0.195:8080/dspace/handle/11099/1205 1989-01-01T00:00:00Z