IntroductionThe Code of Conduct for Responsible Fisheries was developed and adopted on October 31, 1995 [1]. To date, the precautionary approach has been adopted by all leading international fisheries management organizations as the basis of its fishing policy. In particular, the states should clearly define for themselves a specific target and limit reference points for a particular fish stock and, at the same time, actions should be taken if the limits are exceeded, right up to the moratorium on fishing. This means that fishing should be allowed only within biologically safe values [2–17]. Allowable fishing intensity in the water bodies of Kazakhstan is determined by the value of total allowable catches (TAC). In practice, the limits and quotas are the only measures to regulate fishing effort in both Kazakhstan and Russia. Unlike Russia, in Kazakhstan users are assigned not catch quotas, but water bodies or part of their water area.Thus, such a pre-existing limiter as the fishing regime (the number of fishing gear and fisher-men) completely fell out of the control mechanisms of fishing. In 2015–2017, the Fisheries Research and Production Center conducted studies to determine the limit reference points for the stock in order to develop a strategy for careful stock management and sustainable fishing in the main fishing reservoirs of Kazakhstan [18]. It is necessary to establish (and put into practice) the lease of water bodies by users and to conclude the fishing agreements within safe effort that allow, on the one hand, the efficient use of available stocks, and, on the other hand, prevent their reduction. Materials and methodsThe material for our work was studies in the large fishing reservoirs of the Republic of Kazakh-stan: lakes Balkash, Zhaysan, Alakol, Sasykkol; Bukhtarma, Kapshagai, Shardara reservoirs, the Small Aral Sea, the Ural and Kigash rivers during 2015-2019. In total, more than 2000 fishing efforts (catch with fixed nets and seines) were analyzed. The collection of ichthyological material was carried out according to Food and Agriculture Organization (FAO) recommendations and methods accepted in the Commonwealth of Independent States (CIS) [19, 20]. We analyzed not only the number of different fishing gears among users, but also their actual use in different seasons of the year; recorded catch on effort. Results and discussionThe official catch in Kazakhstan is 45 thousand tons, with an estimated total allowable catch of 60-65 thousand tons, while in the middle of the last century up to 100 thousand tons were caught. The official fish catch does not always correspond to the actual one. As in other countries, in Kazakhstan there is the so-called IUU catch (illegal, unreported and unregulated), which is one of the main problems of the fishing industry. At the same time, there is no mechanism for monitoring and regulating the unreported catch, which, according to experts, is very significant. Table 1 shows our calculations of the possible catch of fish by fishing gear at fishing enterprises in the main fishing ponds (based on materials of 2017). Table 1Estimated fish catch in water bodies of Kazakhstan PondsGear used, unitsAmount of effortsEstimated catch, tonsOfficial catch, tonsFish netsFishing ventSeinesUral River and the coastal part of the Northern Caspian Sea19 28511 175242 487 76513 0196 498Lake Zhaysan 24 217–1564 874 60026 2564 617Buhtarma Reservoir2 937–22591 8001 7801 931Lake Balkhash 8 768–558 89 70011 1025 874Small Aral Sea1 2620––3 155 00012 6206 469Shardara Reservoir––127 2002 1601 085The estimated catch is found by multiplying the amount of effort and the average catch by the effort.The number of fishing gear allows fishermen to catch fish 1.5-2 times more than the estab-lished limits. Thus, the possible catch of fish by fishing gear available to fishermen significantly ex-ceeds the recorded (official) catch. The Fisheries Research and Production Center has developed recommendations on the introduction of norms for the permissible number of gear, fishing equip-ment and fishermen for reservoirs and their sections, which served as the basis for the approval in 2018 by the Ministry of Agriculture of the Republic of Kazakhstan “Norms of fishing effort in fishery ponds and (or) areas” (Tables 2, 3).Table 2 Norms of fishing effort in fishery ponds and (or) areasPondsAmount of netsAmount of seinesAmount of fishermenAmount of seinersAmount of boats1*2**1*2**1*2**1*2**1**2**Ural River––23220320232696Kigash R.––42820140214642N. Caspian Sea3005 4003005 400305402366108Lake Zhaisan2001 4008561461 0226421284Buhtarma Res.1832 01933340440111444Shulba Res.3030011010100110440Kapshagai Res.4080012010200120480Shardara Res.––28166428416S. Aral Sea4007 000––407202366108Syrdarya River15060014156014416Lake Alakol4036019109019436Lake Sasikkol2030011510150115460Lake Koshkarkol6060222020––44* – Per 1 fishing site; ** – all fishing sites in pond.Table 3 Norms of fishing effort on Lake BalkhashNumber of siteAmount of netsAmount of seinesAmount of fishermenAmountBoatsSeiners131415106113024031080132035271192172244317641514527612092654555718107473236164820111672920111672101011113211128–64–Total3 60054504120108However, immediately after the introduction of the standards they were sharply criticized by users of fishery ponds and fishing sites. This is understandable, since the possibility of using an unlimited number of fishing gear in a pond has been eliminated. If a certain number of jobs exist at the production site, then it cannot be arbitrarily increased. However, in some cases, the objections of the fishermen are justified. The approved standards do not take into account the important economic component of the fishery – ensuring its profitability, as well as the recommended ratio of passive and active fishing gear.The number of fishermen in the pond should not only meet the criteria for safe effort, but also allow fishing organizations to conduct profitable fishing. What should be the annual catch for a fisherman, taking into account ensuring the profitability of the enterprise?One fisherman must catch 10 000 kg (10 tons) of fish per year. This figure must be taken into account when calculating the number of fishermen in the reservoir. Depending on the fish productivity of the reservoir, this figure in different reservoirs can vary in one direction or the other, but not significantly. Example. Suppose that the annual TAC on reservoir A is 7 000 tons. Next, we will break down the norms of fishing effort by type of fishing gear and fishermen. According to the results of studies, it was found that in pond A the average catch of 1 seine for effort is 500 kg, and the catch due to the fixed net effort 2.5 kg/day. The fishery’s target in large water bodies is to increase the share of active fishing gear (seines) in the fishery, which, in contrast to fixed nets, ensures the fishery’s indiscriminate harvesting of all fish species and size groups of fish allowed for fishing. It is necessary to ensure that at least 2/3 of the volume of fish caught in the pond is mastered by active fishing gear. So, on reservoir A, we calculate:Active fishing gear caught 5,000 tons (about 70% of the total catch). 5 000 000 / 500 = 10 000 fishing efforts / 200 days = 50 seines per pond (there are 7 fishing sites in the pond, then we take 7 seines per 1 site). The catch by fixed nets is 2 000 tons (about 30% of the total catch). 2000000 / 2.5 = 800000 efforts / 200 days = 4000 nets per reservoir. With a norm of 40 nets (1 km in length) per team of two fishermen, the norm for one fisherman is 20 nets. The number of fishermen in reservoir A will be 50 • 10 + 4 000/20 = 700 fishermen. Further, it is already possible to calculate the need for fishing vessels and boats at the rate of two vessels and two boats for one non-water link and two fishermen and one boat for one net link).Table 4 presents the proposals we have developed to optimize the norms of fishing effort in fishing reservoirs. Table 4Recommended fishing effort norms for fishing reservoirs of international and national importancePondAmount, unitsNetsSeinesFishermenSeinersBoatsUral River –323203296Kigash River–282802884N. Caspian Sea2 43837/40040833204Lake Zhaisan 4 3335172751210Buhtarma Res.3 2001430014108Shulba Res.767568543Kapshagai Res.1 400151601565Shardara Res.–252505075Small Aral Sea7 0003570035245Syrdarya River280650619Lake Alakol 900150245Lake Sasykkol 7206661236Lake Koshkarkol –21042Lake Balkhash 3 60054684108180Moreover, the norms have been developed for those reservoirs of international and national im-portance, where commercial fishing is carried out.ConclusionAnalysis of data on fishing in large reservoirs of the Republic of Kazakhstan shows that along with natural changes in the state of fish stocks (e.g., when the water level in the reservoir decreases), the intensity of fishing has the greatest impact on the state of fish stocks. Its excessive increase leads to overfishing and falling of fish stocks. The fishing effort just characterizes the absolute or relative intensity of using technical fishing means, its regulation allows to affect the fish stocks. Target indicators of fishing effort serve as a guideline for maintaining various fisheries management systems in working condition. It is necessary to establish (and put into practice of securing sites and concluding fishing agreements) the norms of safe effort (fishing parameters) that allow, on the one hand, the efficient use of available stocks, and, on the other hand, prevent their decline.