Marking fin spine of juvenile sturgeon (acipenseriformes: acipenseridae) using oxytetracycline and the comparing of growth performance

ABSTRACT This study aimed to describe and validate the formation of the rings in the spine of the pectoral fin and to determine the coherence of the OTC mark with the rings of three species of Caspian Sea sturgeon, the Persian sturgeon (Acipenser persicus), the Starry sturgeon (Acipenser stellatus) and Ship sturgeon (Acipenser nudiventris). Validation was achieved by comparing the total radius of the fin spine of fish of known age after one and two years of growth with the measured radius of the first and second rings in the zone. There was no overlap between the measured radius for the first year and the increase for the second. The Ship sturgeon showed the largest width of the second ring followed by the Persian sturgeon and Stellate sturgeon. The results indicate that the highest growth parameter belongs to the juvenile Ship sturgeon. This research showed that chemically marking the fin spines of juvenile Acipenseridae leads to unbiased estimates and contributes to the knowledge of the population dynamics of these species. The study found that the combination of the dial ring of the pectoral fin spine with growth validated the age estimation in juvenile sturgeon Ship, Persian, and Starry sturgeon.

COEFFICIENTS OF ACCUMULATING CHEMICAL ELEMENTS IN ORGANS AND TISSUES OF RUSSIAN (ACIPENSER GUELDENSTAEDTII, BRANDT, 1833) AND PERSIAN (ACIPENSER PERSICUS, BORODIN, 1897) STURGEONS OF CASPIAN SEA

The article is focused on the possible ways of accumulating chemical elements (zinc, copper, chromium, nickel, lead, mercury) in the organs of aquatic organisms. In the course of the study, the coefficients of accumulating the chemical elements in the organs and tissues were calculated for the Russian (Acipenser gueldenstaedtii, Brandt, 1833) and Persian sturgeons (Acipenser persicus, Borodin, 1897) relative to the water of the northwestern part of the Caspian Sea, bottom sediments and the main objects of their food (Khvalyn goby (Neogobius caspius), Sandpiper goby (Neogobius fluviatilis), Caspian goblin (Benthophilus microcephalus), roach (Rutilus rutilus caspicus)). The studies were carried out according to the standard method of atomic absorption spectrometry. It is shown that the main source of accumulating the studied chemical elements in the organs and tissues of the Russian and Persian sturgeons is the water of the northwestern part of the Caspian Sea. It was found that the bottom sediments of the Caspian Sea act as an additional source of zinc and mercury found in the liver and kidneys of sturgeon species. Based on the calculated accumulation coefficients of chemical elements, there was revealed a predominantly alimentary nature of accumulating copper, nickel and mercury in the organs of both sturgeon species.

Study of the osmotic regulation processing in the juvenile Persian sturgeon, Acipenser persicus. Borodin, 1897 in transfer directly to the Caspian seawater

The aim of this study was to transfer directly juvenile Acipenser persicus from freshwater to the Caspian Seawater (CSW). The fish in different age and size (weight (W) & length (L)) groups (I: 35days, W: 2.75±0.15g & L: 7.93±0.47cm; II: 50days, W: 3.15±0.12g & L: 8.31±0.28cm; III: 65days, W: 4.33±0.12g & L: 9.39±0.29cm; n=90 for each group) and in two different saline water (FW: <0.5‰ and CSW: 12.5‰) were investigated. The fish were transferred directly from FW to CSW. After 168 hours, blood samples were taken from the fish. The results showed that the survival in all groups in CSW was from 56% up to 76% and increased with increasing age and weight of fish. Some hematological parameters and levels of cortisol, osmolarity and ion concentration (Na+, K+, Ca+2 and Mg+2) in the plasma were determined. The functional levels of the mechanism of osmotic and ionic homeostasis were similar in all groups (P>0.05) but differed in experimental media (P<0.05). Significant differences were observed between the levels of plasma ion concentrations in different media (P<0.05). Plasma Na+, K+ and Ca+2 concentrations were higher than those of FW media, but lower than in Brackish water media (P<0.05). Plasma Mg+2 concentrations were lower than those of FW and Brackish water media (P<0.05). The Hct, Hb, MCV, MCH and plasma osmolarity decreased and MCHC and plasma cortisol levels increased with increasing salinity (P<0.05). But the number of WBC and RBC did not change (P<0.05) and reached a stable state. Therefore, it is possible to release juvenile sturgeon directly from FW to CSW with increasing weight and age.

SPECIFIC FEATURES OF METAL ACCUMULATION IN THE RUSSIAN (ACIPENSER GUELDENSTAEDTII, BRANDT, 1833) AND PERSIAN (ACIPENSER PERSICUS, BORODIN, 1897) STURGEON OF THE CASPIAN SEA

In the course of the research, the biological features of the accumulation of microelements by the organs and tissues of the Persian sturgeon in comparison with the Russian, as well as the regularities of the age accumulation of sturgeon were revealed. Studies of the elemental composition of organs and tissues of the Persian (Acipenser persicus, Borodin, 1897) and Russian (Acipenser gueldenstaedtii, Brandt, 1833) sturgeon revealed a number of specific features associated with different rates of metabolic processes in fish: the level of iron, copper, manganese, zinc, and mercury in the Persian sturgeon (Acipenser persicus) in almost all organs and tissues, it was recorded higher than in the Russian, at the same time, the content of cadmium and cobalt indicates its greater accumulation in the organs and tissues of the Russian sturgeon (Acipenser gueldenstaedtii).