russian version

Work of the CRTC on commercial bioresources related to protection of the biodiversity

In 2001 assessment of condition of seals population continued. In Russian Federation such studies are carried out by the Caspian SRIF under SRF financed by the State Committee of Russian Federation of Fisheries. In spite of the warm winter and relatively unfavourable conditions for reproduction, no significant cases of seals mortality were recorded. In June CEP in cooperation with NGO Vector carried out vaccination against CDV of a part of seals population that inhabits island Maly Zemchuzny. In winter 2000-2001 development of methods of assessment of seals abundance commenced. Work was carried out from the helicopter MI-8. The work will continue in 2001. Studies of feeding conditions of the Caspian seals, juvenile recruitment, females" fertility were also carried out.

In April-May CaspSRIF identified a high mortality of Anchovy kilka in the Middle and part of the South Caspian that continued until June-July, then faded. Wide-scale studies of kilka physiology, content of chlorine organic pesticides, heavy metals, hydrocarbons, including PAH in their tissue were carried out.

The highest mortality of Anchovy kilka was recorded in the waters of the Middle Caspian, in the area of Kazakhstan shelf. In spring 2001 an active thermocline was found in the area. It was pretty weak during last 3 years. Water temperature in this part of the sea was 7-8⁰ lower, than in the central part. Trophic studies showed that kilka was underfed due to the shortage of food, especially lack of plankton feeder Eyretemora. Kilka fed on nauplii of Balanus (barnacle) that is less nourishing. The reason is that Mnemiopsis was grazed out the Crustacean. The species did not reach its normal abundance by spring 2001.

Observation of populations of Anchovy kilka showed that recruitment of 2001 was low, at present special survey is carried out to clarify its abundance. Catch of kilka reduced significantly. Catch per vessel reduced during various periods by a factor of 5-10 times.

The main reason of mortality of Anchovy kilka is a joint impact of two stress factors: malnutrition of part of the population and reduced immunity as a result of toxicosis. The highest mortality was recorded in the area of lower temperatures. The factor of volcanic activity on the seabed cannot be excluded, as it increased recently in the South Caspian, in the open sea in the vicinity of the coast of Azerbaijan, Turkmenistan.

Gas blowout could result from the volcanic activity. Hwever, we believe that the main reason was a wide-scale impact of Mnemiopsis on food base of kilka such as abrupt malnutrition. Together with the weak resistance to stress factors resulted from accumulation of hydrocarbons, including PAH (benzopyrene, naphthalene, methylnaphthalene etc.), heavy metals (zinc, copper), in fish tissue, this could cause death of a part of a population, especially in April-May.

In 2001 Russian Federation represented by the CaspSRIF including its structure "Floating University", the Institute of Oceanology named after Shirshov RAN, Azov SRI of Fisheries continued work on assessment of abundance, biomass, spatial distribution of Mnemiopsis including vertical distribution, age structure of the population. At the same time studies were carried out on qualitative and quantitative structure of zooplankton, kilka distribution, its weight, feeding conditions, age structure, size and weight. During the navigation periods 5 surveys were carried out.

A program of experimental work was carried out in Dagestan department of the CaspSRIF in Turaly village.

Various samples of Beroe ovata were taken and put in experimental vessels by specialists of Azov SCI of Fisheries. At present experiments are carried out on Beroe ovata and Mnemiopsis, and their trophic interaction is being studied.

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