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The objective of this study was to evaluate the economic effectiveness of various hormonal products for stimulating the reproduction of the cultured and wild forms of the common barbel Barbus barbus (L.). Three hormonal products were analyzed: Ovopel, Ovaprim (cultured and wild fish) and hCG (cultured fish). The economic effectiveness of hormonal stimulants was analyzed in view of ovulation rates, the price of hormonal products and spawner mortality rates. The cost of hormonal injection per 1000 eggs and 1000 hatchlings was adopted as an indicator of economic effectiveness. The best results were reported for hormonal stimulation using synthetic GnRH analogues during induced spawning of the barbel in a group of cultured fish. The above product’s effectiveness in the controlled spawning of cyprinids is demonstrated by high ovulation rates and high embryo survival rates.
Barbel eggs and fry were exposed from fertilization until 14 days after hatching to 100 μg/l of copper or cadmium. Cadmium, but not copper, significantly reduced larvae survival. Both metals significantly decreased larval growth. The differences in fish body size between the controls and metal-exposed groups increased in time, and were more pronounced in Cd-intoxicated fish. Copper-exposed larvae started exogenous feeding 1 day later than the control. Cadmium-exposed larvae started feeding 4 days after the controls. Both metals reduced yolk utilization rate. The results demonstrated that cadmium was more toxic to barbel larvae than copper.
The aim of this study was to analyze and summarize rearing conditions for larval and juvenile common barbel according to recent research. Barbel larval and juvenile stages achieve very high survival rates (95-99%) irrespective of water temperature or initial stock density. The only factor affecting survival rates during larval rearing Is diet; specifically, this refers to quality and not to the dry or wet type. The best and most predictable effects can be achieved when the larvae are fed with Artemia nauplii. This kind of food is also the best for larval growth rates. The highest growth rate of barbel larvae was obtained at 26-27°C. The optimal temperature for of juvenile growth is 25-26°C. The results presented here are evidence that barbel is a species which is very easy to rear under controlled conditions.
Migration behavior of carp (Cyprinus carpio L.), bream (Abramis brama L.), roach (Rutilus rutilus L.), nase (Chondrostoma nasus L.), barbel (Barbus barbus L.), ide (Leuciscus idus L.), and silver carp (Hypophthalmichthys molitrix L.) is presented. Fishes migrate in different periods of life. The main migrations are spawning migrations, feeding migrations, and wintering migrations. The distances covered by cyprinids differ, and range from several meters to many kilometers. Many species return to spawn in the same places each year, which is known as “homing” or “site fidelity”. Spawning grounds are chosen by fish near shore, where water is well oxygenated, warmer, and provides good food resources. Conditions in these waters are good for the development of fish eggs and then fish larvae.
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