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Copyright of Arab Gulf Journal of Scientific Research is the property of Arabian Gulf University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most of the waterbodies in Bangladesh's north-eastern haor basin have seen a gradual decline in their biodiversity, but little study has been done to determine their current condition. To address this issue, this research was conducted in the Malam beel under the Hakaluki haor - one of the largest wetland resources of the country. The study was conducted using a pre-tested questionnaire and a direct catch assessment survey in the beel. From 11 orders and 32 families, a total of 69 fish and shellfish species were identified. Of the species documented, 15.94% were classified as abundant, 39.13% were common, 27.54% were moderately available, and 17.39% were rare. Among the orders, Cypriniformes accounted for 37.68% of the total fish recorded. The most prevalent family was Cyprinidae found in Malam beel. Based on the findings, it can be concluded that Malam beel is a highly valuable inland open water body that has the potential to function as a key source of fishery resources as well as a gene bank for various fish species. However, some manmade and natural threats such as fishing by dewatering, brush pile fishing, illegal/destructive fishing and siltation were identified during the present study. Therefore, to ensure the sustainable maintenance of these water bodies, ecosystem-based fisheries management involving the local community is strongly advised. [ABSTRACT FROM AUTHOR]

This report presents a review of the commercial and pre‐commercial stage applications of new genomic technologies (NGT) applied to farm animals and their agri/food/feed products. Additionally, a literature review was performed to compile a comprehensive listing of peer‐reviewed research and development stage gene edited animals for food and agricultural applications. A total of 195 publications resulting in live animals were compiled. To date, several developed or ongoing research applications have been authorized for commerce, or judged to be "non‐GMO" hence conventional, in at least one country including knockout tiger pufferfish and red sea bream in Japan; tilapia, cattle, pigs and horses in Argentina; cattle and tilapia in Brazil; and two gene‐edited cattle were granted enforcement discretion in the United States meaning their products can enter the food supply. One application, the targeted exon deletion of a gene resulting in porcine respiratory and reproductive syndrome virus resistance in pigs is formally in the precommercial stage. There are proof‐of‐concept applications in multiple food species testing gene targets for traits of commercial interest. The most common trait category targeted was meat and fibre yield (31%), followed by reproduction (24%), biotic stress (18%), multiple traits (7%), colour (6%), production of hypoallergenic products (5%), product quality (4%), abiotic stress (1%), and other (4%). The majority of these were SDN‐1 applications using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 to introduce small insertions and deletions to inactivate a gene. The large number of applications focused on reproduction is due in part to interest in both single‐sex offspring in numerous industries (e.g. females in the case of egg production), and infertility coupled with germline complementation chimeras (where germline‐competent donor cells are used to replace the germline of an otherwise sterile host of a different genetic background) in multiple species including finfish, chickens, cattle, goats, and pigs. [ABSTRACT FROM AUTHOR]

The banking sector is a key driver of economic growth in Georgia. The sector has been resilient during the COVID-19 pandemic, with low levels of non-performing loans and strong capital buffers. However, the pandemic has had a negative impact on the local economy, leading to a decline in economic activity and a slowdown in credit growth. The post-pandemic period is expected to be challenging for the banking sector, as it will need to support the recovery of the local economy. The sector will need to focus on providing credit to businesses and households, as well as on developing new products and services to meet the needs of customers. This paper discusses the current trends in the development of the banking sector in Georgia in 2019-2022, in relation to the issues of economic growth and the problems and challenges that the pandemic and post-pandemic periods have shown us. [ABSTRACT FROM AUTHOR]

Streptococcosis caused by Streptococcus agalactiae and S. iniae is a significant problem that affects the success of tilapia aquaculture industries worldwide. In this critical review, we summarize the applicable practical strategies which may effectively enhance the world tilapia aquaculture development. Recently, the effect of vaccination and selective breeding programmes has been recognized as valuable tools to control the target disease and other consequent negative impacts caused by chemical and drug application. Advances in sequencing and molecular technologies are vital helpful factors with which to develop robust vaccines and increase the selective breeding programme's precision against streptococcosis. The genomic selection for streptococcosis‐resistant tilapia strains and crucial genomic application for genomics' contribution to the development of novel Streptococcus vaccine, comparative genomics approach identifying vaccine candidates by reverse vaccinology, and next‐generation vaccine design were described. Information from our review is encouraging for practical implementation of the development of vaccination and genomic selection in tilapia for streptococcosis resistance, which may be vital factors to sustain the world tilapia aquaculture industry effectively. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the socio-economic crisis aroused due to the COVID-19 pandemic and associated prevention measures on the coastal riverine island Nalua in Bangladesh. The cross-sectional household questionnaire survey was done among the randomly selected households in the study area. This study revealed that more than 70 percent of the surveyed households had at least one member with COVID-19 symptoms. The local administration and community-based organizations have taken initiatives to enforce the government's order on the island, but about three-fourths of households did not test their family members having COVID-19 symptoms because of fear of isolation and societal barriers. However, whether tested or not, approximately 15 percent of households took steps to isolate the infected person from the rest of the family. The demand for hand washing agents, face masks, and gloves increased in the study area. Island dwellers' food supplies were hampered and about 74 percent were supposed to buy food items at an increased price. For recovering from the educational crisis, the students watched live television classes, participated in online class lectures, and submitted their desired assignments to their institutions. According to survey results, about 39 percent of economically active family members lost their income-generating occupations. To manage their livelihoods, island dwellers have switched their income sources and, in most cases, taken consumer loans. This study suggests that governments, non-government organizations, and community-based organizations need to take effective steps to reduce socioeconomic crises during pandemics. [ABSTRACT FROM AUTHOR]

The silver pride of Bangladesh, migratory shad, Tenualosa ilisha (Hilsa), makes the highest contribution to the total fish production of Bangladesh. Despite its noteworthy contribution, a well-annotated transcriptome data is not available. Here we report a transcriptomic catalog of Hilsa, constructed by assembling RNA-Seq reads from different tissues of the fish including brain, gill, kidney, liver, and muscle. Hilsa fish were collected from different aquatic habitats (fresh, brackish, and sea water) and the sequencing was performed in the next generation sequencing (NGS) platform. De novo assembly of the sequences obtained from 46 cDNA libraries revealed 462,085 transcript isoforms that were subsequently annotated using the Universal Protein Resource Knowledgebase (UniPortKB) as a reference. Starting from the sampling to final annotation, all the steps along with the workflow are reported here. This study will provide a significant resource for ongoing and future research on Hilsa for transcriptome based expression profiling and identification of candidate genes. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Studia Periegetica is the property of WSB University in Poznan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

On the gel, the DNA samples extracted using a commercial DNA extraction kit were appeared as smear (Figure 1a), whereas the DNA integrity was very high in salt-isopropanol precipitation method (Figure 1b). Investigation of genetic sex of GIFT strain of tilapia in Bangladesh using Y-linked Amh marker Keywords: all-male tilapia; Amh gene; aquaculture; GIFT; sex-linked marker EN all-male tilapia Amh gene aquaculture GIFT sex-linked marker 5737 5741 5 10/14/22 20221101 NES 221101 Nile tilapia has complex sex-determining mechanism and the system varies from population to population; even within a population variation has been observed. [Extracted from the article]

This study investigated how agile leadership played its role in managing inter-role conflicts during the chaotic period of the COVID-19 pandemic. The COVID-19 pandemic was much more than the survival of the fittest and coming out of it alive. Organizations were under immense pressure to resume their normal operations in not-so-normal situations. This period of turmoil and agony brought a broad array of inter-role conflicts, which posed challenges for leaders to manage them effectively. The satisfaction at job and the satisfaction in life were the two most important endeavors for the employees to fight. This study explores how leadership agility helped employees manage their work–family and family–work conflicts, consequently impacting life satisfaction and job satisfaction simultaneously. Moreover, role ambiguity, role conflict, and role overload are important intervening role stress factors that impact inter-role conflict management. So, role stress is a moderating factor in the direct relationship between agile leadership and inter-role conflict. This is a two-phased time lag study with a quantitative design for data collection. The first phase of data collection comprises of analyzing the impact of agile leadership on inter-role conflict management, keeping in view the intervening impact of role stress. The second data collection phase examines how inter-role conflicts impacted life satisfaction and job satisfaction during COVID-19. The data were collected from faculty working in higher education institutions in Pakistan, as the education industry was the second major sector that was affected because of COVID-19 after the health care industry. This research found that agile leadership plays a significant role in determining job satisfaction and life satisfaction. Agile leadership during the COVID-19 pandemic helped to manage work–family (AgileL -> WFC -> JS β = 0.1020, p = 0.0112 and AgileL -> WFC -> LS β = 0.1361, p = 0.0014) and family–work conflicts (AgileL - > FWC -> JS β = 0.1598, p = 0.0017 and AgileL -> FWC -> LS b = 0.1160, p = 0.0093) and reduce role stress. Future researchers might include marital satisfaction, as the inter-role conflicts highly impacted marital satisfaction and resultant imbalances among dual-earning couples. Comparative studies in this regard, explaining how dual-earning couples managed to sustain marital health and the role of leadership in developed and developing countries would be enlightening. [ABSTRACT FROM AUTHOR]

Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security. Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms, providing an ideal system to perform sex determination research, one of the important areas in life science. Moreover, sex is also one of the most valuable traits because sexual dimorphism in growth, size, and other economic characteristics commonly exist in aquaculture animals. Here, we synthesize current knowledge of sex determination mechanisms, sex chromosome evolution, reproduction strategies, and sexual dimorphism, and also review several approaches for sex control in aquaculture animals, including artificial gynogenesis, application of sex-specific or sex chromosome-linked markers, artificial sex reversal, as well as gene editing. We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture. [ABSTRACT FROM AUTHOR]

Sex-determining regions have been identified in the Nile tilapia on linkage groups (LG) 1, 20 and 23, depending on the domesticated strains used. Sex determining studies on wild populations of this species are scarce. Previous work on two wild populations, from Lake Volta (Ghana) and from Lake Koka (Ethiopia), found the sex-determining region on LG23. These populations have a Y-specific tandem duplication containing two copies of the Anti-Müllerian Hormone amh gene (named amhY and amhΔY). Here, we performed a whole-genome short-reads analysis using male and female pools on a third wild population from Lake Hora (Ethiopia). We found no association of sex with LG23, and no duplication of the amh gene. Furthermore, we found no evidence of sex linkage on LG1 or on any other LGs. Long read whole genome sequencing of a male from each population confirmed the absence of a duplicated region on LG23 in the Lake Hora male. In contrast, long reads established the structure of the Y haplotype in Koka and Kpandu males and the order of the genes in the duplicated region. Phylogenies constructed on the nuclear and mitochondrial genomes, showed a closer relationship between the two Ethiopian populations compared to the Ghanaian population, implying an absence of the LG23Y sex-determination region in Lake Hora males. Our study supports the hypothesis that the amh region is not the sex-determining region in Hora males. The absence of the Y amh duplication in the Lake Hora population reflects a rapid change in sex determination within Nile tilapia populations. The genetic basis of sex determination in the Lake Hora population remains unknown. [ABSTRACT FROM AUTHOR]

Marker‐5, which is linked to the major sex‐determination gene amhy on LG23, has been used for sex genotyping of various strains of Nile tilapia. Marker‐5 specifically amplifies fragments of approximately 1,422 and 982 bp of the X and Y chromosomes, respectively. Herein, we evaluated Marker‐5 polymorphism in Nile tilapia of Hainan strain, China. Agarose gel electrophoresis showed that in 13 out of 85 female fish, Marker‐5 amplified a larger band, distinct from the standard X‐specific band. Sanger sequencing showed that this larger band was 1,688 bp in length and showed high similarity with both 1,422‐bp X‐specific and 982‐bp Y‐specific fragments. The larger band was proved to be a female sex‐linked allele of Marker‐5 and was labeled as XL. When the polymerase chain reaction (PCR) products of XLY fish, amplified by Marker‐5, were tested by agarose gel electrophoresis, an unusual band, smaller than XL but larger than that of Y fragment, was observed. The unusual band could be a heteroduplex of the XL and Y fragments. In very few XXL male, amhy was found to be linked with 1,422‐bp fragment amplified by Marker‐5. Understanding the Marker‐5 is useful for its utilization in sex‐controlled breeding in farmed Nile tilapia. [ABSTRACT FROM AUTHOR]

Consensus and sex-specific genetic linkage maps for large yellow croaker (Larimichthys crocea) were constructed using samples from an F1 family produced by crossing a Daiqu female and a Mindong male. A total of 20,147 single nucleotide polymorphisms (SNPs) by restriction site associated DNA sequencing were assigned to 24 linkage groups (LGs). The total length of the consensus map was 1757.4 centimorgan (cM) with an average marker interval of 0.09 cM. The total length of female and male linkage map was 1533.1 cM and 1279.2 cM, respectively. The average female-to-male map length ratio was 1.2 ± 0.23. Collapsed markers in the genetic maps were re-ordered according to their relative positions in the ASM435267v1 genome assembly to produce integrated genetic linkage maps with 9885 SNPs distributed across the 24 LGs. The recombination pattern of most LGs showed sigmoidal patterns of recombination, with higher recombination in the middle and suppressed recombination at both ends, which corresponds with the presence of sub-telocentric and acrocentric chromosomes in the species. The average recombination rate in the integrated female and male maps was respectively 3.55 cM/Mb and 3.05 cM/Mb. In most LGs, higher recombination rates were found in the integrated female map, compared to the male map, except in LG12, LG16, LG21, LG22, and LG24. Recombination rate profiles within each LG differed between the male and the female, with distinct regions indicating potential recombination hotspots. Separate quantitative trait loci (QTL) and association analyses for growth related traits in 6 months fish were performed, however, no significant QTL was detected. The study indicates that there may be genetic differences between the two strains, which may have implications for the application of DNA-information in the further breeding schemes. [ABSTRACT FROM AUTHOR]

The Mozambique tilapia (Oreochromis mossambicus) is a fascinating taxon for evolutionary and ecological research. It is an important food fish and one of the most widely distributed tilapias. Because males grow faster than females, genetically male tilapia are preferred in aquaculture. However, studies of sex determination and sex control in O. mossambicus have been hindered by the limited characterization of the genome. To address this gap, we assembled a high-quality genome of O. mossambicus , using a combination of high coverage of Illumina and Nanopore reads, coupled with Hi-C and RNA-Seq data. Our genome assembly spans 1,007 Mb with a scaffold N50 of 11.38 Mb. We successfully anchored and oriented 98.6% of the genome on 22 linkage groups (LGs). Based on re-sequencing data for male and female fishes from three families, O. mossambicus segregates both an XY system on LG14 and a ZW system on LG3. The sex-patterned SNPs shared by two XY families narrowed the sex determining regions to ∼3 Mb on LG14. The shared sex-patterned SNPs included two deleterious missense mutations in ahnak and rhbdd1 , indicating the possible roles of these two genes in sex determination. This annotated chromosome-level genome assembly and identification of sex determining regions represents a valuable resource to help understand the evolution of genetic sex determination in tilapias. [ABSTRACT FROM AUTHOR]

Summary: Crossing Oreochromis niloticus (On) females with Oreochromis aureus (Oa) males results in all‐male progeny that are essential for effective tilapia farming. However, a reproductive barrier between these species limits mating and mass‐fry production. One approach to overcoming this barrier is to select parental stocks of mixed genetic backgrounds, which allow interspecific reproductive recognition, while closely maintaining the genetic profiles for sex‐determination (SD) of the respective purebred species. Here, we test this approach in a data set of 160 On × Oa spawns of 109 male and 100 female parents randomly collected from admixed stocks, and genotyped for microsatellite markers representing the known SD loci on linkage groups (LGs) 1, 3, and 23. Following crossbreeding, the most significant paternal effects on male proportions in progeny were found for LG1‐BYL018 (P < 2 × 10−32) and for LG3‐UNH168 × LG23‐UNH898 interaction (P < 1 × 10−17; R2 = 0.98). Furthermore, a maternal effect for LG3‐UNH168 (P < 9 × 10−7) was associated with low female proportions in progeny (<7%), indicating a non‐Mendelian effect on SD. Eighty‐four males (77%) and 30 females (30%) were selected as parents, based on their genetic profiles for the SD loci that were associated with male production. Of these, 51 of 53 crosses produced all‐male progeny, while two crosses had low female proportions in their progeny (<4%). This suggests that selection could be improved using the causative sequence variation underlying SD on LG3, since the large non‐recombining block of the SD region in purebred Oa readily breaks down in hybrids. Nevertheless, marker‐assisted selection for sex determining loci of admixed parental stocks may be used for all‐male production. [ABSTRACT FROM AUTHOR]

Genetic information is essential for conservation and future aquaculture development of the endangered catfish Rita rita (Hamilton, 1822). Two hundred catfish, R. rita, 50 from four rivers, the Old Brahmaputra, Jamuna, Meghna and Kangsa were collected and analysed to evaluate the genetic diversity and population structure using five microsatellite primers (Cba06-KUL, Cba08-KUL, Cba09-KUL, Phy03-KUL and Phy07-KUL). Four of the five amplified loci were found polymorphic (P95) in all the populations and 46 alleles were recorded with 9 to 14 alleles per locus. Differences were observed in the total number of alleles ranging from 41 to 44, effective number of alleles from 29.96 to 37.46, observed heterozygosity from 0.57 to 0.76, Shannon's information index from 2.09 to 2.30 and polymorphic information content from 0.84 to 0.88 among the four populations. Results exposed the highest levels of genetic diversity in the Meghna population while the lowest in the Kangsa population of R. rita. All the populations were significantly deviated (P < 0.001) from the Hardy-Weinberg equilibrium for all the loci. Nei's genetic distance between populations ranged 0.007 to 0.017 with low overall genetic difference FST = 0.011 and high gene flow Nm = 24.333, indicating that R. rita populations were not subdivided. This study revealed a high level of gene diversity with deficiency in genetic heterogeneity in all the populations of R. rita, emphasising natural management, conservation and rehabilitation measures of this species. [ABSTRACT FROM AUTHOR]

Gilthead sea bream (Sparus aurata) belongs to a group of teleost which has high importance in Mediterranean aquaculture industry. However, industrial production is increasingly compromised by an elevated outbreak of diseases in sea cages, especially a disease caused by monogeneans parasite Sparicotyle chrysophrii. This parasite mainly colonizes gill tissues of host and causes considerable economical losses with mortality and reduction in growth. The aim of current study was to explore the genetics of host resistance against S. chrysophrii and investigate the potential for genomic selection to possibly accelerate genetic progress. To achieve the desired goals, a test population derived from the breeding nucleus of Andromeda Group was produced. This experimental population was established by crossing of parents mated in partial factorial crosses of ∼8 × 8 using 58 sires and 62 dams. The progeny obtained from this mating design was challenged with S. chrysophrii using a controllable cohabitation infection model. At the end of the challenge, fish were recorded for parasite count, and all the recorded fish were tissue sampled for genotyping by sequencing using 2b-RAD methodology. The initial (before challenge test) and the final body weight (after challenge test) of the fish were also recorded. The results obtained through the analysis of phenotypic records (n = 615) and the genotypic data (n = 841, 724 offspring and 117 parents) revealed that the resistance against this parasite is lowly heritable (h 2 = 0.147 with pedigree and 0.137 with genomic information). We observed moderately favorable genetic correlation (R g = −0.549 to −0.807) between production traits (i.e., body weight and specific growth rate) and parasite count, which signals a possibility of indirect selection. A locus at linkage group 17 was identified that surpassed chromosome-wide Bonferroni threshold which explained 22.68% of the total genetic variance, and might be playing role in producing genetic variation. The accuracy of prediction was improved by 8% with genomic information compared to pedigree. [ABSTRACT FROM AUTHOR]

Oestrogenic wastewater treatment works (WwTW) effluents discharged into UK rivers have been shown to affect sexual development, including inducing intersex, in wild roach (Rutilus rutilus). This can result in a reduced breeding capability with potential population level impacts. In the absence of a sex probe for roach it has not been possible to confirm whether intersex fish in the wild arise from genetic males or females, or whether sex reversal occurs in the wild, as this condition can be induced experimentally in controlled exposures to WwTW effluents and a steroidal oestrogen. Using restriction site‐associated DNA sequencing (RAD‐seq), we identified a candidate for a genetic sex marker and validated this marker as a sex probe through PCR analyses of samples from wild roach populations from nonpolluted rivers. We also applied the sex marker to samples from roach exposed experimentally to oestrogen and oestrogenic effluents to confirm suspected phenotypic sex reversal from males to females in some treatments, and also that sex‐reversed males are able to breed as females. We then show, unequivocally, that intersex in wild roach populations results from feminisation of males, but find no strong evidence for complete sex reversal in wild roach at river sites contaminated with oestrogens. The discovered marker has utility for studies in roach on chemical effects, wild stock assessments, and reducing the number of fish used where only one sex is required for experimentation. Furthermore, we show that the marker can be applied nondestructively using a fin clip or skin swab, with animal welfare benefits. [ABSTRACT FROM AUTHOR]

Stocking of all‐male fingerling produced by direct administration of male hormone 17‐α‐methyltestosterone is the most preferred method for present‐day aquaculture of the Nile tilapia Oreochromis niloticus. However, due to the growing concern of negative impact of steroid hormone in food fish, production of 'genetically male' tilapia, which depends on the concrete and thorough understanding of sex determination, has long been a scientific curiosity. The objective of the present study was to identify reliable sex‐linked markers and to evaluate the applicability of those markers in terms of monosex production approach. 'XY' neofemales were produced by using synthetic oestrogen and identified through selective breeding and progeny testing. Three females with progeny not deviating from 3:1 sex ratio (male:female) were designated as 'XY' neofemales and were used subsequently to produce putative YY progeny. Among the fifteen microsatellite markers tested, marker ARO172 was most informative in differentiating male and female genotypes. Twenty‐seven F2 fish from three families were identified as putative YY males based on marker genotyping, and four of them were crossed to produce F3 to validate marker association by progeny testing. The YY males produced 86%–100% male progeny indicating ARO172 a unique sex‐linked marker applicable in marker‐assisted selection. [ABSTRACT FROM AUTHOR]

The aim of the present study was to know the cyclic changes in gonadal maturation and to investigate the various developmental stages of oocytes and testicular germ cells of snow trout, Schizopyge niger. A total of 316 fish specimens were procured from three sites of river Jhelum during November 2016 to October 2017 and the histological analysis of their gonad was carried out. The results of the present study indicates that the male population was found significantly (p < 0.05) higher compared to female population and were reported as (1.6:1; M:F). The highest mean GSI value was recorded in male (12.24 ± 0.89) during the month of March and for female (13.74 ± 0.92) also in the month of March, which indicated that the gonadal development reached its peak during this month. The highest mean oocyte diameter was 1.04 ± 0.20 mm observed in March, showing that the oocyte reached its maturity during this month. Histological study of ovary revealed the evidence of vitellogenic yolk granule stage and ripe mature stage from December to April. While in case of male, four stages of spermatogenesis were distinguished and spermatozoa were highly abundant in the months of March and April. Mean ± SE of absolute fecundity was 3,224 ± 421 eggs and also, the relative fecundity was 69 egg/g body weight. Based on the results of GSI and the analysis of gonad histology, it was observed that the peak breeding season of S. niger occurred in the month of March. It was also noted that spawning period of this fish begins in the month of February and lasts till April with a peak breeding season in the month of March. The present study will provide a baseline information about the appropriate peak breeding of the fish, which will be useful for artificial breeding as well for prevention of fishing from natural habitat. [ABSTRACT FROM AUTHOR]

With the rapid development of next-generation sequencing technologies and bioinformatics, over 50 ray-finned fish genomes by far have been sequenced with high quality. The genomic work provides abundant genetic resources for deep understanding of divergence, evolution and adaptation in the fish genomes. They are also instructive for identification of candidate genes for functional verification, molecular breeding, and development of novel marine drugs. As an example of other omics data, the Fish-T1K project generated a big database of fish transcriptomes to integrate with these published fish genomes for potential applications. In this review, we highlight the above-mentioned recent investigations and core topics on the ray-finned fish genome research, with a main goal to obtain a deeper understanding of fish biology for theoretical and practical applications. [ABSTRACT FROM AUTHOR]

Sex‐specific markers provide significant molecular basis for sex control breeding biotechnology to produce all‐male or all‐female fish in commercial breeding. Redtail catfish (Mystus wyckioides), one of the commercial bagrid catfishes distributed in Southeast Asian, which have a long sexual maturation period that can last 3–5 years and males have apparent growth advantage over females, but its sex determination system remains unknown. In this study, we first applied 2b‐RAD‐seq approach to identify three male‐specific 2b‐RAD‐tags and one male heterogametic SNP locus and validated by blast to the genome survey sequences and PCR amplification in both wild and breeding populations. To get longer sex‐specific region, we performed genome walking and obtained a 4,630 bp of Y‐specific sequence and 4,581 bp of X‐specific sequence from the 2b‐RAD‐tag ref189950 with 92.19% nucleotide identity between them. And 9,923 bp/3,935 bp of Y‐specific sequences and 8,491 bp/5,172 bp of X‐specific sequences were also identified with 77.49% and 57.07% nucleotide identity in ref208528 and ref210837, respectively. Subsequently, three different kinds of sex‐specific primers with different length products were designed based on the detected highly sex differentiated regions and could be used to distinguish males and females both in wild and artificially bred populations. What is more, the X‐specific fragment was discovered to produce the dosage effect association in females and in males. The data suggest that male heterogametic XX/XY sex determination system should exist in the redtail catfish. More significantly, the sex‐specific markers are of great value to protect wild resources and improve the efficiency of all‐male breeding practices for aquaculture in the redtail catfish. [ABSTRACT FROM AUTHOR]

Microsatellites have been utilized most extensively in comparison to other molecular, marker because they can be readily amplified by PCR and the large amount of allelic variation at each locus. These markers are abundant, co-dominant, distributed throughout the genome and are highly polymorphic. These markers in fisheries are useful for characterization of genetic stocks, broodstock selection, constructing linkage maps and marking quantitative traits. The aim of this review is to summarize the current knowledge about the microsatellite markers in fisheries and aquaculture. [ABSTRACT FROM AUTHOR]

The study evaluated the genetic signatures of the fishes from the two populations and compared the pattern of differentiation of the two populations with a view to separating the species from the different populations into possible sub-species. Forty (40) specimens were collected from River Niger (Lokoja) and Asejire Resevoir. The DNA of the twenty (20) specimens from each population extracted from the muscle tissue using phenol-chloroform extraction (PCE) method was subjected to microsatellite DNA analysis. Seven (7) microsatellite markers (Cga01, Cga02, Cga03, Cga05, Cga06, Cga09 and Cga10) were used in the analysis. Microsatellite DNA analysis of the two populations revealed significant differentiation between the two populations as shown by the high values of heterozygosity, low level of inbreeding and non-conformance to Hardy-Weinberg's equilibrium. It is concluded from the study that microsatellite analysis showed a high potentiality for separation of the populations. [ABSTRACT FROM AUTHOR]

Mud crab, Scylla paramamosain is one of the most important crustacean species in global aquaculture. To determine the genetic basis of sex and growth-related traits in S. paramamosain , a high-density genetic linkage map with 16,701 single nucleotide polymorphisms (SNPs) was constructed using SLAF-seq and a full-sib family. The consensus map has 49 linkage groups, spanning 5,996.66 cM with an average marker-interval of 0.81 cM. A total of 516 SNP markers, including 8 female-specific SNPs segregated in two quantitative trait loci (QTLs) for phenotypic sex were located on LG32. The presence of female-specific SNP markers only on female linkage map, their segregation patterns and lower female: male recombination rate strongly suggest the conformation of a ZW/ZZ sex determination system in S. paramamosain. The QTLs of most (90%) growth-related traits were found within a small interval (25.18–33.74 cM) on LG46, highlighting the potential involvement of LG46 in growth. Four markers on LG46 were significantly associated with 10–16 growth-related traits. BW was only associated with marker 3846. Based on the annotation of transcriptome data, 11 and 2 candidate genes were identified within the QTL regions of sex and growth-related traits, respectively. The newly constructed high-density genetic linkage map with sex-specific SNPs, and the identified QTLs of sex- and growth-related traits serve as a valuable genetic resource and solid foundation for marker-assisted selection and genetic improvement of crustaceans. [ABSTRACT FROM AUTHOR]

A high-density genetic linkage map is of particular importance in the fine mapping for important economic traits and whole genome assembly in aquaculture species. The channel catfish (Ictalurus punctatus), a species native to North America, is one of the most important commercial freshwater fish in the world. Outside of the United States, China has become the major producer and consumer of channel catfish after experiencing rapid development in the past three decades. In this study, based on restriction site associated DNA sequencing (RAD-seq), a high-density genetic linkage map of channel catfish was constructed by using single nucleotide polymorphisms (SNPs) in a F1 family composed of 156 offspring and their two parental individuals. A total of 4,768 SNPs were assigned to 29 linkage groups (LGs), and the length of the linkage map reached 2,480.25 centiMorgans (cM) with an average distance of 0.55 cM between loci. Based on this genetic linkage map, 223 genomic scaffolds were anchored to the 29 LGs of channel catfish, and a total length of 704.66 Mb was assembled. Quantitative trait locus (QTL) mapping and genome-wide association analysis identified 10 QTLs of sex-related and six QTLs of growth-related traits at LG17 and LG28, respectively. Candidate genes associated with sex dimorphism, including spata2, spata5, sf3, zbtb38 , and fox , were identified within QTL intervals on the LG17. A sex-linked marker with simple sequence repeats (SSR) in zbtb38 gene of the LG17 was validated for practical verification of sex in the channel catfish. Thus, the LG17 was considered as a sex-related LG. Potential growth-related genes were also identified, including important regulators such as megf9, npffr1 , and gas1. In a word, we constructed the high-density genetic linkage map and developed the sex-linked marker in channel catfish, which are important genetic resources for future marker-assisted selection (MAS) of this economically important teleost. [ABSTRACT FROM AUTHOR]

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The genetic structure of mrigal carp, Cirrhinus cirrhosus was analysed using six microsatellite DNA markers (MFW1, MFW2, MFW17, Bgon22, Barb54, and Bgon17) to detect genetic variations among fish samples from the three rivers, the Halda, the Padma, and the Jamuna in Bangladesh. All the populations showed polymorphism at all loci except Bgon17. Genetic richness of the Halda and Padma populations was indicated by the presence of rare alleles, two in Halda at MFW2 (160 bp) and MFW17 (201 bp), and one in Padma at Bgon22 (96 bp). The highest average number of allele (2.8) was observed in the Halda followed by the Padma (2.6) and the Jamuna (2.4). The observed heterozygosity (Ho) was highest (0.400) in the Padma followed by the Halda (0.383) and the Jamuna (0.377). The highest (0.0257) population differentiation (FST) value was observed between the Halda and Padma populations and the lowest (0.0143) between the Padma and Jamuna populations. The highest gene flow (Nm) was recorded between the Padma and Jamuna populations (17.1756) and the lowest between the Halda and Padma populations (9.4832). The highest (0.037) genetic distance (D) was observed between the Halda and Padma populations and the lowest (0.0195) between the Jamuna and Padma populations. The results indicated a low level of genetic variation regarding allelic richness and heterozygosity among wild stocks of C. cirrhosus and indicated it might be advisable to take necessary measures for the conservation and enhancement of C. cirrhosus genetic resources. [ABSTRACT FROM AUTHOR]

Despite being the second most important aquaculture species in the world accounting for 7.4% of global production in 2015, tilapia aquaculture has lacked genomic tools like SNP-arrays and high-density linkage maps to improve selection accuracy and accelerate genetic progress. In this paper, we describe the development of a genotyping array containing more than 58,000 SNPs for Nile tilapia (Oreochromis niloticus). SNPs were identified from whole genome resequencing of 32 individuals from the commercial population of the Genomar strain, and were selected for the SNP-array based on polymorphic information content and physical distribution across the genome using the Orenil1.1 genome assembly as reference sequence. SNP-performance was evaluated by genotyping 4991 individuals, including 689 offspring belonging to 41 full-sib families, which revealed high-quality genotype data for 43,588 SNPs. A preliminary genetic linkage map was constructed using Lepmap2 which in turn was integrated with information from the O_niloticus_UMD1 genome assembly to produce an integrated physical and genetic linkage map comprising 40,186 SNPs distributed across 22 linkage groups (LGs). Around one-third of the LGs showed a different recombination rate between sexes, with the female being greater than the male map by a factor of 1.2 (1632.9 to 1359.6 cM, respectively), with most LGs displaying a sigmoid recombination profile. Finally, the sex-determining locus was mapped to position 40.53 cM on LG23, in the vicinity of the anti-Müllerian hormone (amh) gene. These new resources has the potential to greatly influence and improve the genetic gain when applying genomic selection and surpass the difficulties of efficient selection for invasively measured traits in Nile tilapia. [ABSTRACT FROM AUTHOR]

Sex-specific markers are powerful tools for identifying sex-determination system in various animals. Bighead carp (Hypophthalmichthys nobilis) and silver carp (Hypophthalmichthys molitrix) are two of the most important edible fish in Asia, which have a long juvenility period that can lasts for 4-5 years. In this study, we found one sex-specific marker by next-generation sequencing together with bioinformatics analysis in bighead carp. The male-specific markers were used to perform molecular sexing in the progenies of artificial gynogenetic diploids and found all progenies (n=160) were females. Meanwhile, around 1 : 1 sex ratio was observed in a total of 579 juvenile offspring from three other families. To further extend the male-specific region, we performed genome walking and got a male-specific sequence of 8,661 bp. Five pairs of primers were designed and could be used to efficiently distinguish males from females in bighead carp and silver carp. The development of these male-specific markers and results of their molecular sexing in different populations provide strong evidence for a sex determination system of female homogametry or male heterogametry (XX/XY) in bighead carp and silver carp. To the best of our knowledge, this is the first report of effective sex-specific markers in these two large carp species. [ABSTRACT FROM AUTHOR]

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Construction of genetic linkage map is essential for genetic and genomic studies. Recent advances in sequencing and genotyping technologies made it possible to generate high-density and high-resolution genetic linkage maps, especially for the organisms lacking extensive genomic resources. In the present work, we constructed a high-density and high-resolution genetic map for channel catfish with three large resource families genotyped using the catfish 250K single-nucleotide polymorphism (SNP) array. A total of 54,342 SNPs were placed on the linkage map, which to our knowledge had the highest marker density among aquaculture species. The estimated genetic size was 3,505.4 cM with a resolution of 0.22 cM for sex-averaged genetic map. The sex-specific linkage maps spanned a total of 4,495.1 cM in females and 2,593.7 cM in males, presenting a ratio of 1.7 : 1 between female and male in recombination fraction. After integration with the previously established physical map, over 87% of physical map contigs were anchored to the linkage groups that covered a physical length of 867 Mb, accounting for ∼90% of the catfish genome. The integrated map provides a valuable tool for validating and improving the catfish whole-genome assembly and facilitates fine-scale QTL mapping and positional cloning of genes responsible for economically important traits. [ABSTRACT FROM PUBLISHER]

Controlling the sex ratio is essential in finfish farming. A balanced sex ratio is usually good for broodstock management, since it enables to develop appropriate breeding schemes. However, in some species the production of monosex populations is desirable because the existence of sexual dimorphism, primarily in growth or first time of sexual maturation, but also in color or shape, can render one sex more valuable.The knowledge of the genetic architecture of sex determination (SD) is convenient for controlling sex ratio and for the implementation of breeding programs. Unlike mammals and birds, which show highly conserved master genes that control a conserved genetic network responsible for gonad differentiation (GD), a huge diversity of SD mechanisms has been reported in fish. Despite theory predictions, more than one gene is in many cases involved in fish SD and genetic differences have been observed in the GD network. Environmental factors also play a relevant role and epigenetic mechanisms are becoming increasingly recognized for the establishment and maintenance of the GD pathways. Although major genetic factors are frequently involved in fish SD, these observations strongly suggest that SD in this group resembles a complex trait. Accordingly, the application of quantitative genetics combined with genomic tools is desirable to address its study and in fact, when applied, it has frequently demonstrated a multigene trait interacting with environmental factors in model and cultured fish species. This scenario has notable implications for aquaculture and, depending upon the species, from chromosome manipulation or environmental control techniques up to classical selection or marker assisted selection programs, are being applied. In this review, we selected four relevant species or fish groups to illustrate this diversity and hence the technologies that can be used by the industry for the control of sex ratio: turbot and European sea bass, two reference species of the European aquaculture, and salmonids and tilapia, representing the fish for which there are well established breeding programs. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the physiochemical characteristics and sensory quality of smoked, coarse-ground catfish sausages and catfish frankfurters by using 100% fillets, 75% fillets with 25% nuggets, and 50% fillets with 50% nuggets (the proportions of fillets and nuggets equaled 100% for each of the three formulations). Pork fat was added to each formulation to bring the final fat content to 20%. Lightness (L*) decreased (p < 0.05) as percentage of nuggets increased in frankfurter and coarse-ground sausages. Based on texture profile analysis results, coarse-ground sausages showed lower (p < 0.05) springiness, cohesiveness, hardness, gumminess, and chewiness than frankfurters. Attributes of aroma, flavor, and texture were not affected (p > 0.05) by catfish fillet percentage but were affected (p < 0.05) by sausage type. In addition, no differences existed (p > 0.05) in consumer acceptability among frankfurter samples, with all samples receiving average scores between “like moderately” and “like very much.” Results indicate that catfish fillets and nuggets could be used to produce catfish frankfurters with acceptable sensory properties. [ABSTRACT FROM AUTHOR]

African cichlids display a remarkable assortment of jaw morphologies, pigmentation patterns, and mating behaviors. In addition to this previously documented diversity, recent studies have documented a rich diversity of sex chromosomes within these fishes. Here we review the known sex-determination network within vertebrates, and the extraordinary number of sex chromosomes systems segregating in African cichlids. We also propose a model for understanding the unusual number of sex chromosome systems within this clade. [ABSTRACT FROM AUTHOR]