Aquaculture in Serbia

<em>Abstract</em>.—Numerous natural resource agency and media reports have alleged that Asian carps were introduced into the wild through escapes from commercial fish farms. This chapter traces the chronology associated with importations of Asian carps to North America and discusses the likeliest pathways of their introduction to the wild. The U.S. Fish and Wildlife Service first imported an Asian carp species, grass carp <em>Ctenopharyngodon idella</em>, in 1963. Since then, state and federal agencies, universities, and private fish farmers have interacted to import Asian carps, to develop production technologies, and to promote their use in both public and private sectors in a number of different states. These importations and stocking, whether in confinement or, in the case of the grass carp, sometimes in open waters, were purposeful and legal. Asian carps were introduced to take advantage of their unique food preferences (planktivory by silver carp <em>Hypophthalmichthys molitrix </em>and bighead carp <em>H. nobilis</em>, herbivory by grass carp, and molluscivory by black carp <em>Mylopharyngodon piceus</em>). The first known accidental release of diploid grass carp was in 1966 by the U.S. Fish and Wildlife Service in Stuttgart, Arkansas. Other early reports of grass carp in the wild were from waters in Alabama, Georgia, and Florida. Grass carp were reported from the wild in 1970, 2 years before the first private hatchery received grass carp. By 1972, grass carp had been stocked in open water systems in 16 different states. Silver carp and bighead carp were first imported purposely by a commercial fish producer in Arkansas in 1973. All silver and bighead carps were transferred to the Arkansas Game and Fish Commission by March 1974 where they first successfully spawned silver carp and bighead carp later that year. The first report of silver carp in the wild was in Arizona in 1972, although strong evidence suggests that this may have been a misidentification, followed by reports in Arkansas in the wild in 1975. The Arkansas report occurred 2 years before bighead carp and silver carp were returned to private hatcheries for commercial production. By 1977, silver carp and bighead carp had been introduced to Alabama, Arizona, Arkansas, Illinois, and Tennessee. Research and stockings of silver carp and bighead carp were conducted by at least six state and federal agencies and three universities in seven states in the 1970s and 1980s. Public-sector agencies, which were successful in encouraging development and use of Asian carps that today are in commercial trade, are the likeliest pathways for the earliest escapes of grass carp, silver carp, and bighead carp.

In situ study on the control of toxic Microcystis blooms using phytoplanktivorous fish in the subtropical Lake Taihu of China: A large fish pen experiment

Fish were used as a food source during the hunting-gathering period of humans. It continued its development and transformation with the developments in science and technology and continued its importance today. The demand for fish, which is a valuable food, is increasing day by day. Fish consumption is increasing day by day, even in countries that generally supply their animal protein needs from terrestrial animals. Today, the increase in the population, the increase in the demand for fish, and the developments in science and technology, have caused an increase in the amount of fish caught, but this also puts pressure on the fish reserves. At this point, aquaculture gains great importance. Increases in both fish production amounts and the number of producers are quite high. Between 1990 and 2018, the increase in fish caught was 12.24%, while the increase in aquaculture was 525.28%. 46% of the world's total fish production and 52% of people's fish consumption are obtained from aquaculture. In aquaculture, firstly carp and trout were bred. In 2018, aquaculture production reached 114.5 million tons (including plants and others), with a sales value of $263.6 billion. In Turkey, as in the rest of the world, the development in aquaculture is very important. Aquaculture production, which was 5 782 tons as of 1990, reached 373 356 tons as of 2019 with an increase of 6457.2% between 1990 and 2019. The production of finned fish is also dominant in Turkey. Among these species, especially sea bass, sea bream and trout farming takes the first place. The fact that the total of the three species constitute 97.2% of the total aquaculture production clearly reveals the importance of sea bass, sea bream and trout farming. The fact that the total of the three species constitute 97.2% of the total aquaculture production clearly reveals the importance of sea bass, sea bream and trout farming. As both a source of export income and an employment provider, fish and fish products trade makes a significant contribution to economic growth in developing countries. For these reasons, the geographical distribution of sea bass, sea bream and trout in Turkey and their importance as an economic activity are discussed in this study.

We studied daily periodicity, taxonomic composition and annual variation of fish larvae abundance from a survey of the Zhaoqing section of the Pearl River over a 3-year period, 2006–2008, and collected 52 species, in eight families and 16 orders. The fish larval samples were numerically dominated by six species, Barbel Chub (Squaliobarbus curriculus) 33.1%, Black Guangdong Bream (Megalobrama hoffmanni) 20.6%, Yellowfin (Xenocypris argentea) 15.4%, Mud Carp (Cirrhina molitorella) 10%, Common Sawbelly (Hemiculter leucisculus) 4.3%, and Freshwater Bream (Parabramis pekinensis) 3.1%. These six species accounted for 86.5% of total numbers. Black Carp (Mylopharyngodon piceus), Grass Carp (Ctenopharyngodon idellus), Silver Carp (Hypophthalmichthys molitrix) and Bighead Carp (Aristichthys nobilis) are four of the most economically important fish species in China, and accounted for approximately 4.6% of the total. When compared with historical records from 1931, there are obvious changes in the fish larvae community. Chinese Sturgeon (Acipenser sinensis), Seasonal Shad (Macrura reevesi) and Long Spiky-head Carp (Luciobrama macrocephalus) populations have disappeared and there are also decreases in several other economically important fish populations. We observed a delay in spawning time of Black Carp, Grass Carp, Silver Carp and Bighead Carp, which may be the result of the hydrological regime change in the Pearl River. We used canonical correspondence analysis (CCA) and cross-covariance function (CCF) to analyze the relationship between fish larvae and environmental variables. Our results clearly show that discharge affects the majority of fish larvae, with the various species having different responses. Larval abundances of 15 species such as Black Carp, Grass Carp, Silver Carp, Bighead Carp, Mud Carp and Black Guangdong Bream are significantly and positively related to the discharge. Other species such as Chinese Noodlefish (Leucosoma chinensis) and Rhinogobius olivaceus are negatively related to the discharge. Abundances of larval Mosquitofish (Gambusia affinis), Common Carp (Cyprinus carpio) and Eleotris oxycephala were not related to the discharge. As most economic fish species are affected by discharge, we also conclude that changes of hydrological regime, mainly caused by river damming, will result in the decline of fisheries resources in the Pearl River. The findings of this study have important implications for our ability to model the responses of fish larvae to environmental flows for the purpose of river regulation.

The primary structures of growth hormones of three cyprinid species: Bighead carp, silver carp, and grass carp

Juvenile blue swimming crab, Portunus pelagicus were reared over 31 days in two different systems namely recirculating aquaculture system (RAS) and conventional aquaculture system (CAS) to evaluate the water quality parameters, growth, and its body composition. The juvenile crab, weighing of 0.95 ± 0.18 g and stocking was at 40 crabs m-2 and fed twice per day with a commercial shrimp pellet. During the experimental time, significantly (P <0.05) increment in dissolved oxygen (DO) (6.42 ± 0.13), low level of ammonia- nitrogen (0.04 ± 0.10) and nitrite-nitrogen (0.04 ± 0.10) were recorded in RAS than conventional aquaculture system (CAS) (DO: 5.99 ± 0.24; ammonia- nitrogen: 3.83 ± 1.59; nitrite-nitrogen: 0.71 ± 0.58). The carapace width, weight gain and specific growth rate (SGR) were significantly (P <0.05) higher in RAS. Protein content (22.65 ± 0.11%) in crab also were significantly (P <0.05) higher in RAS compared with crab protein (21.41 ± 0.12%) cultured in CAS. Although the survival rate was slightly higher in the juveniles reared at CAS, however it was not significantly different comparing with the individuals reared at RAS. The results strongly suggested that the use of RAS may improve the growth performance and maintain the better water quality for the crabs in captivity.

There is growing interest in using recirculating aquaculture systems (RAS) to raise noble crayfish Astacus astacus a valuable and once plentiful food species in Europe, now a highly endangered species. The growth and survival of A. astacus was compared in growth trials in RAS and open-pond systems (OPS) over a period of 2 months. Energy and lipid content of available diets and crayfish tissue were also determined. Growth of A. astacus during summer was significantly (p < 0.01, one sample t test) higher in OPS (SGR 1.23) than in RAS even at the highest feeding ration provided at 5 % bw/d−1 (RAS HI SGR 0.78 ± 0.06). OPS crayfish also had significantly (p < 0.01 OPS vs. all RAS treatments; Pairwise Wilcoxon) higher lipid content (8.51 %) than RAS crayfish (RAS HI 5.73 %, RAS MED 6.93 %, RAS LOW 5.92 %). Survival rates in RAS were, however, 100 % compared with previous observations in OPS of approx. 70 %. While results showed OPS growth exceeds than that in RAS in the short term, RAS survival rates and annualized growth performance may outweigh this disadvantage, particularly if optimal artificial diets for RAS holding are provided. Feed and crayfish analysis indicated that culturing A. astacus in RAS require a diet protein content exceeding 30 % and lipid content of <13 %, indicating that the carp diet supplied was not optimal. RAS culture allows this valuable species to be cultured in controlled, disease-free enclosed systems—resulting in high-value food products as well as high-quality seedlings for restocking purpose.

The production of the whiteleg shrimp Litopenaeus vannamei now accounts for approximately 75% of the total shrimp production in Indonesia. The techniques used to produce whiteleg shrimp in Indonesia are still dominated by conventional rearing strategies using open-pond systems, which often contribute to unpredictable culture performance and weak sustainability. Alternative production strategies of closed aquaculture systems, including the recirculating aquaculture system (RAS) and hybrid zero water discharge-recirculating aquaculture system (hybrid system), have been developed and implemented for higher productivity, stability and sustainability of whiteleg shrimp grow-out production in Indonesia. Despite the positive aspects of the application of closed aquaculture systems in shrimp aquaculture, the differences in the characteristics of shrimp grown in closed RAS and hybrid systems compared to open-pond systems remain unclear. This study aims to investigate the differences in the metabolite profiles of shrimp grown in intensive closed aquaculture systems, including an RAS and hybrid system, compared to those of shrimp grown in a semi-intensive, open, earthen pond system by means of non-targeted GC-MS metabolite profiling. Shrimp cultured in the closed systems (RAS and hybrid system) and an open system (pond) were harvested and subjected to GC-MS non-targeted metabolomics analysis. A total of 112 metabolites were annotated from shrimp samples and subjected to principal component analysis (PCA). The metabolites annotated from GC-MS mainly included organic compounds, proteinogenic and non-proteinogenic amino acids, sugars, nucleosides and fatty acids. The results of principal component analysis showed several metabolites with high variable importance in projection (VIP) scores, including shikimic acid, β-alanine, uric acid, hypoxanthine, inosine, homocysteine, methionine, phenylalanine, tryptophan and lysine, as the main metabolites differentiating the shrimp grown in the three production systems. Our findings showed that shrimp cultured in different aquaculture systems exhibited distinct metabolite profiles, and the metabolites showing high VIP scores, including shikimic acid, β-alanine, uric acid, hypoxanthine, inosine, homocysteine, methionine, phenylalanine, tryptophan and lysine, may serve as candidate markers to indicate the differences in shrimp from different production systems.

Fishes utilize several different species-specific reproductive strategies adapted to their environment. Invasive species may display reproductive strategies that allow successful reproduction in varying environments, such as batch and protracted spawning. Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix, referred to as bigheaded carp, are invasive species that have been introduced worldwide. In some invaded ranges, they either have a protracted spawning period and/or spawn multiple times in a season, which can be advantageous in novel environments. Reproductive strategies can vary between river systems or with environmental conditions, and understanding differences in strategies can improve management of bigheaded carp. To determine reproductive strategy, we evaluated the histology of spawning capable ovaries from Silver Carp (n = 58) and Bighead Carp (n = 38) collected during May–September 2016 and June 2017 from Pools 17–20 of the upper Mississippi River (UMR). We found that 87.9% of Silver Carp (n = 51) and 86.8% of Bighead Carp (n = 33) had an ovary that contained primary growth, cortical alveolar, and vitellogenic oocytes simultaneously. Multiple stages of oocytes within an ovary indicated that individuals were capable of spawning multiple times during a single year, and the presence of postovulatory follicle complexes demonstrated that individuals had already spawned while oocytes were still present. Based on histological samples, bigheaded carp appear to be indeterminate batch spawners, with oocytes continuing to develop throughout the spawning period. Silver and Bighead carp in the UMR may exhibit protracted and batch spawning and employ flexible spawning strategies among different river systems, which can increase the probability of successful recruitment in a variable environment.

Fish polyculture may increase the maximum standing crop of a pond by utilizing a wider range of available food and ecological niches. To identify a better polyculture system for the fish production practiced in southern South America, a 167‐d experiment was conducted in 16 earthen ponds (250 m2). The control group contained a traditional combination of carps: 35% common carp (CC), 35% grass carp, 15% silver carp (SC), and 15% bighead carp (BC). The T25%, T50%, and T75% groups consisted of ponds in which CC was replaced by jundiá (JN), and SC and BC were replaced by Nile tilapia at substitution rates of 25%, 50%, and 75%, respectively. The yields of the T25%, T50%, and T75% groups were higher than those of the control group. The effluents generated in the control and T25% groups had lower total phosphorus levels than those generated in the other groups. Considering that all the substituted groups demonstrated better growth performance than the control group and that the T25% group was also better in terms of effluent quality and economic performance, we concluded that fish polyculture in South America would be optimized using a species ratio tested in T25% groups.

The occurrence of heavy water blooms of cyanobacteria (blue-green algae, BGA) in surface water is receiving increasing attention world wide as a potential health concern. This is a serious water quality problem because many of the cyanobacterial species or strains are able to produce potent toxins. The most frequently reported cyanobacterial toxins are cyclic heptapeptide hepatotoxins, microcystins, isolated from several species of the freshwater genera Microcystis, Planktothrix (Oscillatoria), Anabaena and Nostoc. They are potent and specific inhibitors of the serine threonine family of protein phosphatases, especially PP1 and PP2A. In order to minimize public exposure to MCs, the World Health Organization (WHO) has set a provisional guideline value of 1 μg/L for MC-LR in drinking water and established the tolerable daily intake (TDI) for consumption of cyanobacteria products contends MCs (0.04 μg/kg/day). Aquatic animals could bioaccumulate microcystins(cyanobacteria hepatotoxins) and so, beyond water, the ingestion of contaminated food represents a human health risk. In order to evaluate the potential risk of their ingestion, this study was mainly investigated the residue levels and distribution features of microcystins in fish from eutrophicated Lake Dianchi, a hypertropic lake in Yunnan Province containing toxic cyanobacteria blooms all the year round. Samples of silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis) and grass carp (Ctenopharyngodon idellus) were collected in the biomanipulation test area in Lake Dianchi respectively in April and September, 2003. Microcystins in different tissues were all analyzed by enzyme-linked immunosorbent assay (ELISA) and the concentration was expressed as microcstin-LR equivalent. The results showed that microcystins presented in all samples, mainly distributing in liver, kidney and digestive tracts, and little in the muscle and the non-digestive tract organs. Different residue levels of microcystins were obviously in different fishes. Concentrations of microcystins in liver and kidney, the target organs of silver carp as well as bighead carp were significantly higher than that in grass carp. On the other hand, the residue levels of microcystins were also changeable along with seasons. Concentrations of microcystins in fish samples in April were lower than that in September. Finally, the safety assessment of the microcystin in fish muscle was also evaluated. According to the standard recommended by WHO, we calculated that the concentration of microcystins in fish muscle of all samples were not above the limit for human consumption. Then, we simply concluded that microcystins in fish muscle had not yet endangered to the human health only existed in the potential health risks. &amp;nbsp;

Bighead carp (Hypophthalmichthys nobilis), silver carp (Hypophthalmichthys molitrix), and grass carp (Ctenopharyngodon idella), collectively referred to as Asian carp, are invasive species that have been introduced into the Mississippi River basin. The expansion of Asian carp into the Missouri River is not well understood and knowledge of population characteristics within this river are lacking. The objectives of this study were to describe the length-weight relationships (condition) of Asian carp from 2003 to 2007 in the Missouri River downstream of Gavins Point Dam, South Dakota and Nebraska to St. Louis, Missouri. All total, 388 bighead, 75 silver, and 111 grass carp were measured and weighed. Short bighead weighed significantly less in the upper Missouri River from Gavins Point Dam to the Platte River compared to fish of the lower Missouri River from the Grand River to the Mississippi River. Conversely, long bighead carp in the upper Missouri River attained greater weights than fish of similar length downstream. Though not significant, condition similarly varied between the upper and lower Missouri River for silver carp and grass carp.

Species-specific bioaccumulation and risk prioritization of psychoactive substances in cultured fish

Nile tilapia is the second most important freshwater fish for human consumption worldwide and it is produced under many different conditions. Even though genotype by environment interaction (GEI) can arise due to many factors, most studies with tilapia have focused on water quality on pond and cage systems. Therefore, the objective of the current work was to evaluate GEI on body weight (BW) of Nile tilapia raised in biofloc technology (BFT), Cage, and recirculation aquaculture systems (RAS) from 100 to 350 days of age. A Bayesian multi-trait random regression model (MTRRM) with age as random regression covariable was employed to evaluate the temporal trend of GEI. Estimated genetic correlations between BFT and RAS were above 0.7 for almost any combination of ages evaluated (Figure 1). However, genetic correlations between Cage at ages below 150 days with either BFT or RAS at any other age were positive but below 0.5. The posterior means of heritability for BW were found to reach peaks of 0.40, 0.38 and 0.29 around 230 days for RAS, BFT, and Cage respectively (Figure 2). Conversely, the ratio between common family environment and phenotypic variances presented an overall decreasing trend with minimums around 0.22, 0.15 and 0.10 at 230 days for Cage, RAS, and BFT, respectively. The MTRRM has shown to be a powerful statistical tool to assess changes across time for genetic parameters of interest. In conclusion, GEI was found to be dynamic across time, with stronger effects between Cage and both BFT and RAS if selection is promoted prior to 150 days. However, GEI is negligible for most of the situations considered if selection is performed after 200 days of age in either BTF or RAS, with the possibility of achieving better indirect selection results if selection is performed around 230 days.

Recirculating Aquaculture System (RAS) was chosen as an alternative for sustainable and low-impact mangrove crab cultivation. One of the main challenges in using RAS is determining the optimal feeding frequency. Inappropriate feeding can cause slow growth, increased mortality, and decreased water quality. This study aimed to analyze the effect of trash fish feeding frequency on the growth of mangrove crab (Scylla serrata) reared in RAS. The method used is an experimental method with a completely randomized design of 3 treatments and 4 replications. The research treatments tested were the frequency of feeding with FPP 01 once a day at 10 pm; FPP 02 twice a day at 10 pm and 5 pm; FPP 03 three times a day at 10 pm, 8 am and 5 pm. The parameters observed were survival, weight growth, carapace length growth, carapace width growth, specific growth rate and molting rate. The research data were analyzed using analysis of variance at a 95% significance level. The results showed that the frequency of feeding did not significantly affect the growth and survival of mud crabs in RAS. The frequency of feeding once is optimal to achieve maximum growth in mud crab cultivation using the RAS system with a survival rate of 100±0.00%, weight growth of 52.00±21.17 g, carapace length growth of 1.90±0.87 cm, carapace width growth of 1.60±0.70 cm, specific growth rate of 5.04±0.14%/day and molting rate of 67.00±0.58%.