Cyprinid Research Articles

Food and Feeding Habits of Osteochilus vittatus Valenciennes, 1842 and Barbodes binotatus Valenciennes, 1842, in Tamblingan Lake, Bali

Tamblingan Lake is the smallest lake in Bali and is inhabited by various species of fish, which are from the Cyprinidae family, namely bonylip barb and spotted barb. Information regarding the food and feeding habits of bonylip barb and spotted barb fish in Tamblingan Lake is unavailable. This study aims to determine and analyze the food and feeding habits of bonylip barb and spotted barb fish in Tamblingan Lake. Fish sampling was conducted from January to June 2019 in Tamblingan Lake using modified gill nets with a net size of 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm. Fishing was carried out at five stations with water characteristics representing the condition of Tamblingan Lake. Bonylip barb fish obtained during the study comprised 216 individuals, while the Spotted barb had 180 individuals. The average value of the relative intestinal length of bonylip barb fish ranged from 4.34 to 5.53, while that of the spotted barb fish was 0.89 to 1.30. The average value of the gastric fullness index of film fish ranges from 1.34 to 4.77, while the spotted barb is 0.32 to 0.42. The total IRI value of bonylip barb fish food in Tamblingan Lake is 924.32, while the spotted barb is 1,232.62, with the highest IRI value in both species coming from plankton. Bonylip barb and spotted barb in Tamblingan Lake developed a generalist feeding strategy with plankton food groups (planktivorous). Information related to these fishes can be used to formulate fish resource management in Tamblingan Lake.

ASSESSMENT OF FISH STRUCTURE COMMUNITY AT GREATER ZAB RIVER NEAR ASKI-KALAK CITY,ERBIL

The structure of fish community was evaluated before and after Aski-Kalak City at Greater Zab River, Erbil Province, Iraq during the period from November 2020 to October 2021. A total of 1582 specimens belonged to 25 fish species were collected and reached to 570 Kg of total weights. These fish were mostly belonging to Cyprinidae family and one for each Mugilidae, Siluridae, Bargridae, Sisoridae and Mastacembelidae. According to fish occurrence in (S1), there were five fish species be as resident, 8 and 10 species as seasonal and rare respectively. The annual values of fish species, weight and catches effort 10.7, 184 and 33.25 Kg/hour respectively, and in (S2) fish species of 6, 6 and 11 as resident, seasonal and rare respectively.The annual values of fish species, its weight and catches were 10.7, 210 and 38.59 Kg/hour respectively. The present study concluded that section of Greater Zab River (S2) was suitable for fish composition more than(S1).

Chromosome-level genome assembly of the ratmouth barbel, Ptychidio jordani

The ratmouth barbel (Ptychidio jordani) is a critically endangered freshwater fish from the Cyprinidae family, primarily due to overfishing and habitat disruption. To address the challenges of its shrinking wild populations and the difficulties in artificial reproduction, we sequenced, assembled, and annotated a high-quality chromosome-level genome of P. jordani using next-generation short-read sequencing, third-generation long-read sequencing, and Hi-C sequencing. The final genome assembly was 1.14 Gb, consisting of 25 chromosomes with a contig N50 of 25.14 Mb and a scaffold N50 of 42.91 Mb. We identified 25,183 protein-coding genes, 751.75 Mb of repeats, and 19,373 ncRNAs. Methylation loci on most chromosomes ranged from 1,000 to 3,000 per 100 kb window. Gene expression levels across various tissues were analyzed, revealing 12,135 (caudal fin), 11,465 (liver), 14,438 (gill), 12,413 (heart), 8,301 (spleen), and 3,578 (kidney) differentially expressed genes compared to muscle. The comprehensive genomic and transcriptomic resources generated here will aid in understanding the ecology, adaptation, and environmental responses of P. jordani, supporting future research and conservation efforts.

Large Intraspecies Variation in Stable Isotope Composition of the Muscle Tissues in Fish of the Genus <i>Cyprinion</i> (cyprinidae) from Middle East

Significant individual variation of nitrogen and carbon isotope composition (δ 15 N and δ 13 C values) in white muscle tissues was found in samples of three cyprinid fish species, Cyprinion macrostomus (periphytonophage), Cyprinion kais (benthophage), and Luciobarbus schejch (omnivore), collected in a small tributary of the upper Tigris system (Turkey). In particular, exceptionally low value (1.7‰) and abnormally wide intraspecific variability (from 1.7 to 15.8‰) of δ 15 N were observed in C. macrostomus . Despite samples were collected synchronously and syntopically, very broad range of δ 15 N values points out possible heterogeneity of the samples. The studied watercourse is located in the zone of agriculture with intensive chemicalization and pollution of the river by mobile forms of nitrogen (mostly ammonium) could play a significant role in lowering δ 15 N values, especially in the periphytonophage. Along with that, fish with high (normal) δ 15 N values are supposedly recent migrants that came from a large river for joint spawning with resident fish. The pollution of water bodies as well as the presence of migrations should be taking into account in stable isotope analyses-based studies on trophic ecology of fishes.

DNA barcoding of seven cyprinid fish species in the Iraqi Inland waters using mitochondrial COI gene sequence

إن عائلة Cyprinidae هي أكبر عائلة سمكية في المياه الداخلية العراقية. تاريخيا وصفت أنواع الأسماك الشبوطيات بواسطة القياسات المظهرية التقليدية. تعتبر أنواع أسماك عائلة Cyprinidae في العراق مهمة من النواحي البيئية والاقتصادية. في حين أن التشابه المورفولوجي بين أنواع أسماك الشبوطيات جعل تحديد الأنواع ليس أمرا سهلا. اختيرت شفرة الحامض النووي لتأكيد التصنيف وايضاح التنوع الجيني بين الأنواع المتشابهة العائدة للجنس نفسه. جمعت سبعة أنواع من أسماك الشبوطيات Luciobarbus barbulus، L. xanthopterus، L. kersin، L. esocinus، Arabibarbus grypus، Cyprinus carpio، و Acanthobrama marmid من نهر شط العرب والأهوار وخزان سد الموصل. تم تضخيم جين الميتوكوندريا Oxidase C Cytochrome للجين المستهدف وتحليل التتابع النيوكليوتيدي. اختيرت بادئات مخصصة لهذا الغرض. أستخدم برنامج Chromas لمعالجة نتائج التتابع النيوكليوتيدي. وأظهرت النتيجة أن التتابع النيوكليوتيدي تراوح بين 600-657 زوج قاعدي. في حين كشفت الشجرة الوراثية neighbor joining tree المتحصلة من موقع Clustal Omega عن أنواع Luciobarbus الأربعة التي تتجمع في فرعين مركزيين، بينما تباعدت الأنواع الثلاثة الأخرى. وتمت مقارنة توزيع النيوكليوتيدات إحصائيا لأنواع الأسماك المدروسة باستخدام برنامج CLC bio . أثبتت نتائج ترميز الحامض النووي باستخدام تسلسل الجينات COI وجود أربعة أنواع من أسماك Luciobarbus المستقلة. أثبتت الدراسة إن أستخدام جين COI كشفرة وراثية للحامض النووي ناجحا ودقيقا في تحديد الأنواع. أودعت التتابعات في البنك الجيني تحت رموز OM669701 و OM669699 و OM669702 و OM669705 و OM669703 وOM669700 و OM669704. إن هذه الدراسة هي نقطة الانطلاق لمشروع ترميز الحامض النووي لجميع الشفرات الوراثية للأنواع السمكية في المياه الداخلية العراقية. بالإضافة إلى ذلك، ستكون نتائج الدراسة مفيدةً جداً في برنامج الحفاظ على الأنواع المحلية في المياه الداخلية العراقية.

The Complete Mitochondrial Genome of the Luciocyprinus langsoni (Cypriniformes: Cyprinidae): Characterization, Phylogeny, and Genetic Diversity Analysis.

Background: Luciocyprinus langsoni is a species belonging to the Cyprinidae family. The objective of this study is to gain a comprehensive understanding of its evolutionary history and genetic characteristics. Methods: The complete mitochondrial genome of L. langsoni was determined using overlapping PCR. A phylogenetic analysis was conducted based on 13 protein-coding genes from 48 species. A population genetic diversity analysis using the COI gene and a selection analysis of 13 protein-coding genes were also performed. Results: The mitogenome is 16,586 base pairs long and consists of 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, and two control regions. It has a high adenine-thymine (A + T) content. The phylogenetic analysis confirms the placement of L. langsoni within the subfamily Cyprininae. The population genetic diversity analysis reveals low variability in the Hechi Longjiang population. The selection analysis shows that all 13 protein-coding genes have evolved under purifying selection with Ka/Ks ratios below 1. Conclusions: These results enhance our understanding of L. langsoni's evolutionary history and lay a genetic foundation for future studies in population genetics and phylogenetics.

A new rainbow gudgeon of Sarcocheilichthys (Teleostei: Cyprinidae) from Fujian Province, China with redescriptions of S. hainanensis

The teleostean family Cyprinidae is a megadiverse fish taxon that occupies most of the freshwater biomes of the world. The cyprinid genus Sarcocheilichthys of the subfamily Gobioninae is represented by a total of 14 nominal species, most of which are distributed in the vast continent of China. Our recent field collections and surveys in river systems of Fujian Province, southern China, had discovered a cyprinid fish that was recognized herein as a Sarcocheilichthys species new to science. The undescribed species, temporarily known as the Hanjiang rainbow gudgeon, is most similar to S. nigripinnis but can be well distinguished by differences in meristic counts, dorsal fin blotch patterns, and the morphology of oromandibular structures and genital organs. A detailed redescription of the valid Hainan rainbow gudgeon, S. hainanensis, is also provided herein.

Morphological and molecular identification of tissue nematode <i>Philometroides strelkovi</i> (Chromadorea: Dracunculoidea) from three cyprinid species in the North of Primorsky Region

The paper presents a redescription of the parasitic nematode Philometroides strelkovi (Chromadorea: Dracunculoidea) based on the new morphometric data. New hosts from the Cyprinidae family (Rhodeus sericeus, Hemiculter leucisculus, Hemibarbus labeo) and locality – the Luchegorsk reservoir belonging to the Amur River basin (Pozharsky district of Primorsky Krai in the south of the Russian Far East) have been described. For the first time, sequences of the 18S rRNA marker gene have been obtained for P. strelkovi. On the basis of genetic data, we performed phylogenetic reconstruction and showed the clustering of P. strelkovi, separate from the sister species P. moraveci, confirmed by high statistical support at branching nodes and the size of genetic distances — 0.11–0.56% between P. strelkovi and other representatives of the genus, along with intergeneric divergence of 4%. In the light of new molecular data, the question of the artificiality of the genera Philometroides and Philometra is raised.

Fish-inspired dynamic charging for ultrafast self-protective solar-thermal energy storage.

Solar-thermal energy storage (STES) within solid-liquid phase change materials (PCMs) has emerged as an attractive solution to overcome intermittency of renewable energy. However, current storage systems usually suffer from slow charging rates, sacrificed storage capacity, and overheating tendency. Inspired by the thermoregulation behavior of Cyprinid fish, here, we present a quick-responsive, ultrafast, large-capacity, overheating-protective STES strategy. We fabricate a liquid-infused solar-absorbing foam charger that can rapidly advance the receding solid-liquid charging interface to efficiently store solar-thermal energy as latent heat and spontaneously float upward to cease the charging process upon overheating. This bioinspired dynamic charging is adaptable to a variety of PCMs, unlocking the potential for safe and efficient utilization of renewable thermal energy.

Alteration of Immune Function and Gut Microbiome Composition in Carassius auratus Challenged With Rahnella aquatilis.

Rahnella aquatilis as an emerging pathogen can cause bacterial enteritis in cyprinid fish such as crucian carp Carassius auratus. Currently, the characterisation of immune function and gut microbiome composition in C. auratus orally challenged by R. aquatilis were yet unknown. In this study, we therefore investigated the changes of histopathology, white blood cells (i.e., LEU, NEU and LYM), serum biochemical indicators (e.g., CRE, CK and CHO) and digestive enzyme activity (e.g., LYS, AST, ALT, GSH-Px and AKP), as well as complements and immune-related genes (e.g., C3, F2, LysC, TLR3, MyD88, TGF-β, TNF-α and IL-15) that were significantly altered after the oral administration of R. aquatilis KCL-5. Moreover, the gut microbiome composition and diversity were analysed by using 16S rRNA gene high-throughput sequencing analysis. The correlation analysis showed that the high abundance of phylum Proteobacteria, Actinobacteria, Firmicutes and Fusobacteria was related to the pathogenesis of enteritis caused by oral infection. KEGG enrichment analysis indicated that fatty acid, carbon and pyruvate metabolism were significantly increased pathways (p < 0.05). To our best knowledge, this is a rare report of physicochemical properties and gut microbiome in C. auratus by R. aquatilis infection, which will provide a scientific reference for the clinical diagnosis and prevention of bacterial enteritis in cyprinid fish.

Morphological, Histological, and Phylogenetic Characterization of Myxobolus branchioepidermis n. sp. (Myxosporea: Myxobolidae) Infecting the Gills and Skin of the Oranda Goldfish (Carassius auratus).

Myxobolus Bütschli, 1882 is a highly important genus of fish myxozoans, consisting of many species that cause serious diseases in ornamental cyprinid fish species in different geographic areas by infecting a wide range of organs. This study describes a new Myxobolus species infecting the gill lamellae, gill rakers and skin epidermis of goldfish (Carassius auratus) from Mohammadshahr, Iran, based on detailed morphological, histological and molecular analysis. Mature spores were small and spherical in shape, consisting of two symmetrical shell valves in frontal view, measuring 10.3 (9.8-10.9) μm in length and 10.5 (10.3-11.2) μm in width. Two equal-sized relatively pyriform polar capsules were 5.4 (3.9-6.0) μm long and 4.5 (3.7-5.2) μm wide. The polar tubules were coiled with 4-6 turns. A comparative analysis of the morphological and molecular data confirmed that this species is distinct from other identified myxosporeans. Plasmodia in the cutaneous tissue were found in the epidermis, causing extensive hyperplasia of Malpighian cells and mild inflammatory infiltration. In the gill tissue, plasmodia affected only one side of the lamellae, leading to hyperplasia of the lamellar epithelium, edema, and lymphoplasmacytic branchitis. A novel myxozoan species, Myxobolus branchioepidermis n. sp., has been proposed. The study provides a comprehensive analysis of the morphological, histological, and molecular characteristics of this parasite, which infects the gill lamellae and epidermal layer of the skin in oranda goldfish (C. auratus). The identification of this new species adds to the growing body of research on myxozoan parasites and highlights its potential impact on ornamental fish aquaculture.

The occurrence of digenean trematodes in some cyprinid fish from Belchishta Wetland (Macedonia)

Abstract. Belchishta Wetland is the biggest wetland ecosystem in Macedonia and hosts a variety of plant and animal species. Belchishta Wetland is included in the Emerald National Network of R.N. Macedonia and is suggested for nomination as a Natura 2000 site. This study aimed to determine the occurrence of digenean trematodes, as well as their prevalence and intensity of infestation in some cyprinid fish from Belchishta Wetland. During the parasitological investigations on the intestinal tract of some cyprinid fish species (chub - Squalius squalus; Ohrid minnow - Pelasgus minutus, and minnow - Phoxinus lumaireul) from Belchishta wetland, 3 species of digenean trematodes were established, as follows: Allocreadium isoporum was found in chub (Squalius squalus) with the prevalence of 9.09 % and intensity of infestation 1.50; Plaigioporus stefanskii was found in Ohrid minnow (Pelasgus minutus) with the prevalence of 9.52%, and intensity of infestation 2.00; and Pseudochetosoma salmonicola was found in minnow (Phoxinus lumaireul) with the prevalence of 10.00% and intensity of infestation 2.00. The total prevalence in all cyprinid fish amounts to 9.33%. Findings of all digenean trematodes represent a first record for the parasite fauna of fish from Belchishta Wetland, while Plaigioporus stefanskii and Pseudochetosoma salmonicola are found for the first time in Macedonian waters.

Fish Distribution in Lacustrine and Riverine Biotopes of Bratsk Reservoir Based on the Results of Hydroacoustic Surveys

Abstract Fish distribution in different areas of Bratsk Reservoir has been studied using hydroacoustic equipment. The average abundance of fish decreases (r = –0.70; p &lt; 0.05; R 2 = 0.49) from the near-dam reach (214 ± 34 ind./ha) to the water area in the upper reaches of the reservoir (113 ± 43 ind./ha). A similar relationship is observed in the dynamics of the abundance of early juveniles and the immature fish population. However, such relationship has not been found in fish with a size of more than &gt;100 mm, which with a low abundance are relatively evenly distributed along the longitudinal axis of the reservoir (10.5 ± 6.6 ind./ha). The common perch (Perca fluviatilis Linnaeus, 1758) is the most abundant species in the reservoir, its highest concentrations are recorded in the lower lacustrine part of the reservoir (139 ± 22 ind./ha). Less abundant cyprinids (Cyprinidae) (41 ± 15 ind./ha) and whitefishes (Salmonidae, Coregoninae) (12 ± 4 ind./ha) are more evenly distributed along the longitudinal axis of the reservoir. Temperature stratification of the water column is an important factor in the ecological differentiation of the fish population in the reservoir. The major part of the ichthyomass consisting of relatively warm-water fish species from the families Percidae and Cyprinidae (common roach (Rutilus rutilus (Linnaeus, 1758) and common bream (Abramis brama (Linnaeus, 1758)) is concentrated in the warming up epilimnion. The fish population in the cold hypolimnion consists of single individuals of the Baikal omul (Coregonus autumnalis (Georgi, 1775)) and peled (C. peled (Gmelin, 1789)). Transverse distribution of fish depends on the presence of a runoff flow. At relatively high flow rates, fish begin to avoid the midstream part in the studied sites of the reservoir and concentrate in the floodplain areas (R 2 = 0.54; p &lt; 0.0001).

Histopathology of the Haplorchis taichui infection in the freshwater fish, Tigris kingfish, and Tigris barb (Cypriniformes: Cyprinidae) from Iran.

Flukes can cause severe and lethal diseases in various animals, including fish. Both adult and larval stages of flukes are found in fish. Haplorchiasis is an infection of fish gills by heterophyid trematodes such as Haplorchis taichui. To detect this parasite, the gills of 30 Tigris kingfish and Tigris barb collected from the Shapour River in Kazerun, Fars province were found to be parasitized with metacercarial cysts of a heterophyid trematode identified as H. taichui. Histopathological examination of the infected fish gills revealed cartilage proliferation, severe hyperplasia, fusion, S-forming, shortening and thickening, distortion, and displacement of affected secondary gill filaments leading to deformities of the filament structure, clubbing, telangiectasis, and hyperemia. Although the gill damage was evident and potentially life-threatening for the cyprinid fish, the examined fish showed no clinical signs. This finding indicates that H. taichui is pathogenic; therefore, prevention of infection and treatment should be a priority.

Comprehensive assessment of fish diversity and water health in river Indus, Khyber Pakhtunkhwa, Pakistan.

Fish diversity and water quality are vital indicators of the health of freshwater ecosystems, however these systems are increasingly threatened by environmental changes and anthropogenic activities. This investigation aimed to assess the fish diversity and evaluate the physicochemical parameters of water at Ghazi Swabi near Tarbela Dam, River Indus, Khyber Pakhtunkhwa, Pakistan, between March and June 2020. Monthly water samples were collected and analyzed for various physicochemical parameters such as temperature, dissolved oxygen (DO), total dissolved solids (TDS), pH, turbidity, salinity, and concentrations of heavy metals including lead (Pb), copper (Cu), cadmium (Cd), and mercury (Hg). Using various nets and traps the fish specimens were collected with the help of local fishermen. Morphometric and meristic analyses were conducted to identify the species, while systematic keys were used to remove misidentifications. A total of 110 fish specimens were collected, representing 7 species across 6 genera, 3 families, and 3 orders. The family Cyprinidae was the most abundant, with species including Puntius conchonius, Puntius waageni, Crossocheilus diplocheilus, Barilius modestus, and Aspidoparia morar. The Belonidae family was represented by Xenentodon cancila, and the Ambassidae family by Chanda nama. Physicochemical analysis showed that the water quality remained within permissible limits for aquatic life, however higher levels of certain heavy metals were detected, which may pose long-term risks. The study concluded that the fish diversity at Ghazi Swabi near Tarbela Dam reflects a moderately healthy ecosystem, the presence of heavy metals in the water raises concerns about future ecological health. Regular monitoring and mitigation efforts are recommended to preserve biodiversity and maintain water quality. The study suggests the need for sustainable management practices to protect freshwater ecosystems from anthropogenic impacts.

Spatiotemporal Ultrastructural, Histological, and Morphometric Changes in the Buccal Cavity of Grass Carp (Ctenopharyngodon idella) During Fingerling, Yearling, and Adult Stages.

Grass carp (Ctenopharyngodon idella) is a Cyprinid fish of aquacultural and research importance. The buccal cavity represents the gateway of the digestive tract. The present study investigated the adaptational changes involving various components of the buccal cavity of fingerling (three months posthatching, mph), yearling (12 mph), and adult (48 mph) C. idella using scanning electron microscopy, histology, and morphometry. The upper and lower lips appeared uninterrupted at the three studied stages and were limited caudally by the upper and lower jaws. The jaw epithelium was the thickest part of the buccal epithelium; ultrastructurally, it appeared smooth with ridge-like borders in fingerlings that transformed into microgrooves in yearlings. In adult C. idella, the jaw mucosa was organized into dome-shaped masses separated from each other by tight furrows. Each mass was formed from several keratinocytes with corrugated surfaces that featured numerous microdepressions. Except for the jaws, taste buds, mainly of type I, and acidic and neutral goblet cells were observed throughout the mucosa of the buccal cavity, and their densities were highest along the mucosal folds of the palate and oral floor, suggesting a principal role for these parts in both gustation and food lubrication. This study is the first to report age-associated spatiotemporal changes in the buccal cavity of grass carp and will serve as a fundamental reference during the interpretation of various types of oral pathologies in teleost.

Noninvasive Methods Unveil the Trophic Transmission of the Tapeworm Ligula intestinalis in Gull-Billed Terns.

Recent developments in microscopic and molecular tools have allowed the implementation of new approaches for assessing parasitic infections in wildlife populations. This is particularly important for the noninvasive detection and quantification of endoparasites in live animals. Here, we combined copromicroscopic (Mini-FLOTAC) and molecular (qPCR) techniques to detect the infection of the macroparasite Ligula intestinalis (Cestoda, Pseudophyllidea) in fresh droppings of Gull-billed Terns Gelochelidon nilotica (Charadriiformes, Laridae) breeding in southwestern Spain. Additionally, we sequenced the cytochrome b gene in parasite isolates from Gull-billed Terns (definitive host) and Common Bleak Alburnus alburnus (second intermediate host) sampled around tern colonies to explore potential genetic differences between the isolates. The qPCR test showed a higher prevalence (18%; in 13/73 samples) than Mini-FLOTAC (9%; in 8/88 samples), indicating that qPCR was more sensitive for diagnostic purposes than fecal flotation alone. Although the agreement between both techniques was substantial (84.2%) mainly due to the large number of uninfected samples, only Mini-FLOTAC allowed us to quantify parasite shedding. When combining techniques, the prevalence of infection did not differ between adults and chicks, suggesting frequent trophic transmission from parents to their offspring via food provisioning. Phylogenetic analyses identified four haplotypes in the isolates from Gull-billed Terns and Bleak, all of which were placed within a European clade composed of tapeworms recovered exclusively from phylogenetically derived cyprinid fish. This, combined with the short lifespan of mature tapeworms, suggests that Gull-billed Terns became infected after consuming infected fish around their breeding colonies rather than on their West African wintering grounds. Altogether, our results represent the first record of L. intestinalis in Gull-billed Terns and the first molecular characterization of the parasite in the Iberian Peninsula. This integrative coprodiagnostic protocol can be applied to other host-parasite systems, allowing researchers to study helminth infections in wild populations using a noninvasive approach.

Age-Dependent Enhancement in Fecundity and Ova Diameter of &lt;i&gt;Schizopyge niger&lt;/i&gt; (Heckel, 1838) in Dal Lake, Kashmir

Understanding the reproduction and recruitment pattern is essential for successful conservation of a species. Accurate estimates of fecundity plays acrucial role in comprehending fish population dynamics. The snowtrout, Schizopyge niger, is a Cyprinid fish widely distributed throughout the lakes of Kashmir valley and is one of the most important commercial fish species. In this study, we examined the age-dependent reproductive perfor-mance of female S. niger, aiming to gain insights into its breeding characteristics for the development of an optimal brood-stock management plan. The study involved 78 female S. niger specimens collected from Dal Lake during the spawning season, representing age groups of 2+, 3+, 4+, 5+, and 6+ years. Fecundity and ova diameter showed an increasing trend from age 2+ (3,971 eggs; 1.45 mm) to age 6+ (10,501 eggs; 2.00 mm). Total fecundity exhibited positive correlations with age, total weight, ovary weight, and ova diameter. Additionally, there was a positive correlation between ova diameter and fish age, with the highest fecundity and largest ova diameter observed in the 6+ years age group. Among each age group, fecundity and ova diameter varied significantly (p &lt;0.05). Based onthese findings, for optimal broodstock management of S. niger, it is recommended to use females of the6+ years age group after assessing the quality of eggs.

Passage efficiency through fishways of species of the family Cyprinidae and their management implications for fragmented rivers

The contemporary management of fragmented river systems is in a trade-off between the societal benefits of instream barriers (e.g. hydropower, flood risk management) and the ecological harms of their adverse impacts on fish populations. The consequent fragmentation can be mitigated through fishway construction, with mitigation performance measured using species-specific passage rates and efficiencies. There is, however, a bias in passage efficiency studies towards diadromous fishes and, although fish of the Cyprinidae family play a significant role in the fish assemblages of rivers worldwide, their passage efficiencies are poorly understood. Here, systematic review and meta-analyses assessed the passage efficiencies of cyprinid fishes through fishways that have been measured using telemetry methods. Passive integrated transponder (PIT) telemetry was the most common evaluation method of passage efficiency due to their high read rates and relatively low costs versus alternative telemetry methods. These methods revealed cyprinid passage efficiencies were highest through vertical slot fishways and lowest through nature-like constructions, with overall passage rates comparing favourably to anadromous salmonid fishes. Fish were most active during spring and summer, with passage and associated movements often related to spawning. Passage rates of non-native fishes were also higher than for native fishes. Despite the growing acknowledgment of how fishways influence potamodromous fish dispersal and distribution in rivers, passage data remain scarce, preventing managers and policy-makers from making informed decisions on optimal passage solutions for multiple fish species in highly fragmented rivers.

The association of certain lipid metabolism indicators and light regimes in salmonids and cyprinids in aquaculture

Purpose of the review: analysis of the effect of the photoperiodic factor based on indicators of lipid metabolism in Salmonid and Cyprinid fish species.Methods used: comparative analysis of literature and own experimental data.Results: The length of daylight (photoperiod) is one of the most important abiotic factors affecting the behavior, reproduction, metabolism, growth and development of fish. The changes in the lipids and fatty acid constituents execute a significant role in the adaptation of aquatic organisms to new light conditions. Certain parameters of lipidogenesis can serve as a reliable indicator of the normal route of metabolic processes in the organism. It is widely known that photoperiod regimes are used in aquaculture to optimize the cultivation of various species of aquatic organisms, including the most common Cyprinids and Salmonids. The specificity of the reaction of lipid metabolism to the effects of various lighting modes is shown: in cyprinids, the reaction can be multidirectional depending on the species (including its absence), while in Salmonids on example of Atlantic salmon, a change in the lipid profile in the direction of smoltification is observed. The role of combining the photoperiod with other factors, such as feeding and climatic features of the region, are discussed.Significance: The results can contribute to a better understanding of the adaptive processes in fish and optimize the conditions for their artificial rearing.