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The small indigenous fish (SIF), having length of about 25 cm is locally available in the small water resources viz. wetlands, canals, streams etc. and affordable to the poor people also. These are important food item as animal protein, vitamins and minerals sources in the diet of human beings. The objective of this review is to investigate the availability and importance of SIF in nutritional security and income generation of the community. Published and unpublished sources were used to obtain appropriate data. This study interprets actual availability of different species of SIFs, capture and culture resources, consumption pattern and marketing channels etc. A literature review was conducted to highlight the research attempt made to enhance the socio-economic condition of rural sector and as a result it offers important guidelines to popularize SIFs for nutritional security. In India a total of 765 native freshwater fish species documented, out of which about 450 are categorized as small indigenous fish species. The maximum diversity of the SIF's has been recorded from the North East region followed by Western Ghat and Central India. Review indicates an ardent need of focused research efforts towards the development and conservation of these fishes before they become extinct. [ABSTRACT FROM AUTHOR]

Freshwater fish are in a perilous state with more than 30% of species considered critically endangered. Yet significant ecological and methodological complexities constrain our ability to determine how disturbances are impacting native fish communities. We review current methods used to assess the responses of fish communities, especially native fish, to disturbances, with a focus on lakes. These methods include contemporary population surveys, manipulative experimental approaches, paleolimnological approaches and Indigenous Knowledge and social histories. We identify knowledge gaps, such as a lack of baseline data for native fish, an inability to assess the impact of historical disturbances, stressor response dynamics in contemporary multi‐stressor environments, and natural disturbance regimes. Our assessment of the current methods highlights challenges to filling these knowledge gaps using the reviewed methods. We advocate strongly for the implementation of an integrative approach that combines emerging technologies (i.e. molecular‐based techniques in contemporary surveys and paleolimnology) and underutilised knowledge streams (i.e. Indigenous Knowledge and social histories) which should be used in concert with conventional methods. This integrative approach will allow researchers to determine the key drivers of decline and the degree of change, which will enable more informed and successful management actions. [ABSTRACT FROM AUTHOR]

Non-indigenous parasite fauna of freshwater fish has not been studied extensively in Croatia, despite the long history of introductions and translocations of alien fish species into inland waters. Negative implications for aquaculture production and wild native fish species have been frequently associated with the introduction of non-native parasite species. Hence, the present paper attempts to lay out a historical overview of the suspected localities, time frames and pathways of introduction for nonindigenous fish parasites into inland waters of Croatia, therefore producing a list of species. In total, 16 non-native fish parasites have been recorded in inland waters of Croatia, aquaculture establishments being identified as initial points of introduction. However, a paucity of information exists on the overall prevalence of infection as well as the economic impact on aquaculture production. In addition, limited information is available about the presence and potential ecological impact of non-indigenous parasites on endemic fish fauna in areas of high biodiversity, such as the water bodies of the Adriatic Sea Basin. Therefore, there is an urgent need and opportunity for multidisciplinary cooperation between different stakeholders, including government, scientists, in both biological and veterinary disciplines, and the industry, with the aim of extensive surveys to determine the potential impact on aquaculture production and wild fish population of high conservation value. [ABSTRACT FROM AUTHOR]

Inland open-access fisheries of India are important resources that contribute significantly to the national economy while providing livelihood to millions. The majority of these resources are suitable for aquaculture, with a high potential for enhanced inland fish production. Enclosures (cages and pens) installed in such waters are useful for rearing fingerlings for enhancement programmes and table-fish production. Floating cages are most suitable for waterbodies vulnerable to occasional flooding, while pen enclosures installed in marginal areas of floodplain wetlands can be suitably reinforced to protect the fish during floods. Small indigenous fishes can be introduced into pens to increase their productivity. This paper reviews enclosure technologies in the inland open waters of India and discusses the socioeconomic benefits, ecological advantages, and climate resilience of these technologies. These factors may encourage their adoption and lead to an increase in fish production in the large inland waters of India. [ABSTRACT FROM AUTHOR]

Suckers (Catostomidae Cope, 1871) are a diverse family of freshwater fishes native to North America and East Asia. Ethnographic data indicate suckers were harvested by Indigenous peoples throughout the region and frequently of comparable importance to salmon. Suckers were taken at various times of the year through angling, netting, spearing, and other methods. Once harvested, they were, depending on local tastes and customs, consumed fresh and/ or dried. As evidenced by the existence of First Sucker Ceremonies, the taxon's presence in myths, and descriptions of suckers as being a source of spiritual powers, catostomids were also spiritually important to some Indigenous peoples. The variability in the dietary and spiritual importance, capture, and preparation of suckers that is evident in the ethnographic record underscores the dynamism of human-sucker interactions in northwestern North America. [ABSTRACT FROM AUTHOR]

Basic information on length–weight relationships for a number of small indigenous tropical freshwater fish species is still sparse or not available on the FishBase. The present study reports the weight–length relationships of four species from the Ganga River in India. A total of 795 fresh fish specimens of Pethia gelius, Corica soborna, Parambassis baculis and Aborichthys elongatus were collected from four different locations along stretches of the Ganga River from June 2017 to August 2018. The r2 and b values for the four fish species ranged from 0.949 to 0.998 and 2.55 to 2.849, respectively. Length–weight relationships for P. gelius, P. baculis and A. elongatus represent the first information from the Ganga River. A new record for the maximum size of C. soborna was documented as 8.54 cm TL and 4.25 g. [ABSTRACT FROM AUTHOR]

Manipur is one of the north eastern states of India and it is rich in freshwater fish diversity. Among the small indigenous fishes of Manipur, Pethia manipurensis is an economically important fish having both food and ornamental value. For the taxonomic placement of this species among the cyprinid fishes, molecular characterization is conducted by using mitochondrial cox1 gene sequences. Partial sequences of mito. cox1 gene of thirty seven cyprinid species were down loaded from NCBI Genbank and the nucleotide sequence 602 bp were generated from two species i.e. Pethia manipurensis and Puntius sophore for present analysis. Here total 628 characters, 144, 459, 267 and 192 were conserved, variable, parsimony informative and singleton respectively. The average nucleotide frequencies are 26.4% (A), 29% (T), 26.4% (C), and 18.2% (G). The dendogram constructed by both Neighbour-Joining and Maximum Likelihood trees resulted in similar topologies with five clusters with eight sub-clusters which can indicate the taxonomic positions of Pethia manipurensis. [ABSTRACT FROM AUTHOR]

Rapid reaction to the initial discovery of invasive alien species (IAS) is key to eradication, but this is often frustrated by lack of resources and coordinated actions. However, examples of successful eradications may encourage and empower others to follow. Chub (Squalius cephalus) were illegally introduced into the River Inny in Ireland in the late 1990s or early 2000s, reputedly by anglers. The habitat in this river is favourable for chub and, should this species establish, it would likely compete with the indigenous fish communities and impact on other flora and fauna. Central Fisheries Board (now Inland Fisheries Ireland) coordinated chub removal operations and provided the necessary resources (manpower and equipment) to effectively remove chub from this large river. Three electric fishing crews supported by two tank boats and land-based personnel were required in each operation to effectively remove the chub. These crews worked on this task each year between 2006 and 2013. Between 2006 and 2008, 24 adult and two juvenile chub were removed and euthanised. In 2008, two chub were radio-tagged, released back to the river and tracked monthly for 12 months. Over the next two years these "Judas" chub, and two untagged male chub that were located in proximity to the tagged fish, were removed from the river. Intensive electric fishing of the river and regular contact with the local angling community between 2010 and 2017 revealed no further chub specimens. Monitoring of the fish populations in the river will continue but it is suspected that chub may have been eradicated from this river system and, hence, from the island of Ireland. This provides a rare case study of the potential to eradicate aquatic IAS when rapid reaction is resourced and coordinated. [ABSTRACT FROM AUTHOR]

Discovered in the late 1920s, 3,4-didehydroretinol (DROL, vitamin A2) plays a significant biological role in freshwater fish. The functions of this vitamin have been investigated but to a far lesser extent than those of retinol (ROL, vitamin A1). A recent study indicating all-trans DROL has 119-127% vitamin A biological activity compared to that of all-trans ROL suggests the significance of DROL for addressing vitamin A deficiency (VAD) in comparison to ROL may be currently overlooked. Freshwater fish such as small indigenous fish species (SIS), with high DROL content can be a promising dietary source for reducing VAD in areas where SIS are readily available and consumed. In this paper, the discovery and biological relevance of DROL are reviewed and furthermore, the vast potential of production and consumption of DROL-rich SIS in food-based strategies to combat VAD in Bangladesh and other developing countries with high prevalence of VAD is highlighted. [ABSTRACT FROM AUTHOR]

Microplastic (MP) pollution has pressing concerns regarding environmental health and the availability of safe food for humans. Information on the occurrence of MP in freshwater biota in the Indian scenario is currently lacking. The present study examined MP contamination in edible and non-edible tissues of widely consumed freshwater fishes. All the fish species (n = 35/species) analyzed had microplastic contamination with the highest MP abundance of 7.86 ± 2.0 items/individual in Channa punctatus followed by Labeo rohita (4.17 ± 0.6 items/individual) and Labeo bata (3.03 ± 0.4 items/individual); whereas MP abundance in small indigenous fishes (SIF) such as Salmostoma bacaila and Puntius amphibius accounts for 0.83 ± 0.13 and 0.77 ± 0.2 items/individual respectively. The principal component analysis results showed a 77.434% variance from two components identified for MP distribution. Fibre type MP was the most dominant type besides fragments and pellets that opined the type of MP required for ecotoxicity assessment, the need of the hour. Raman spectroscopy analysis confirms high-density and low-density polyethylene-type polymers. Evidence of MP in edible tissue indicates the translocation phenomenon resulting in human exposure through the consumption of biota contaminated with MP. Risk assessment revealed a low risk of MP based on its abundance while polymer type indicates a high risk for the fish species investigated. A thorough investigation of the level of adsorbed organic contaminants in the MP is warranted to address the interactive effects on biota. To the best of our knowledge, this is the first detailed report on MP contamination and its risk assessment in Indian freshwater fishes. [Display omitted] • Microplastics (MP) occurrence in gills, GIT, and muscle were quantified. • MP abundance trend was C. punctatus > L. rohita > L. bata > S. bacaila > P. amphibius. • Fibre-type MP was recorded more than pellets and fragments. • Polymeric characterization revealed LDPE and HDPE-type polymers. • MP abundance poses negligible risk whereas polymer type denotes a high risk for biota. [ABSTRACT FROM AUTHOR]

Simple Summary: Bangladesh has substantially increased aquaculture production over the last few decades, and the exotic species share a significant portion of the total fish production. Although exotic species are contributing to aquaculture production, a few of them are causing biodiversity loss and genetic erosion of native species. The African catfish Clarias gariepinus is a highly carnivorous species and predates small indigenous freshwater fishes when escaping into natural water bodies. In addition, the hybridization of C. batrachus and C. gariepinus is considered a threat to the indigenous population. Although the government of Bangladesh has banned the farming of C. gariepinus, this species has been identified in local markets, and evidence of hybridization between C. gariepinus and C. batrachus has been found. This study revealed genetic erosion of native C. batrachus by the gene sequences of cytochrome c oxidase subunit I and cytochrome b. The phylogenetic tree confirmed the occurrences of hybridization between C. gariepinus and C. batrachus. Genetic erosion in the native catfish population is alarming for aquaculture sustainability and biodiversity conservation in Bangladesh. The African catfish Clarias gariepinus has been introduced for aquaculture in Bangladesh due to the scarcity of indigenous C. batrachus fingerlings. However, the government of Bangladesh has banned the farming of C. gariepinus due to the carnivorous nature of this species. Recently C. gariepinus has been reported by fish farmers and consumers in Bangladesh, and unplanned hybridization between native and exotic species has been suspected. This study attempts to know the purity of C. batrachus by analyzing mitochondrial genes. Both directly sequenced and retrieved Cytochrome C Oxidase subunit I (COI) and cytochrome b (Cytb) genes from C. gareipinus and C. batrachus were analyzed by MEGA software. The morphologically dissimilar C. batrachus showed the least genetic distance (0.295) from C. gariepinus, which provided evidence of hybridization between the two species. Maximum likelihood (ML) phylogenetic trees showed that C. batrachus from Bangladesh did not cluster with C. batrachus of other countries, instead C. batrachus clustered with the exotic C. gariepinus. The suspected hybrid formed sister taxa with the exotic C. gariepinus. The study corroborates the genetic deterioration of C. batrachus by unplanned hybridization with the invasive C. gariepinus. Unplanned hybridization has deleterious consequences; therefore, immediate action is necessary for aquaculture sustainability and biodiversity conservation in Bangladesh. [ABSTRACT FROM AUTHOR]

The aboriginal ichthyofauna of the Balkhash basin consists mainly of endemic fish species. By the end of the last century, indigenous fish species were driven out of Lake Balkhash and the Alakol Lakes remain the largest refuges of aboriginal fish fauna. Knowledge of regularities of the modern distribution of the indigenous fishes is crucial for biodiversity conservation as well as restoring aquatic ecosystems. The modern diversity of fish species was investigated there in this study. Significant changes for the indigenous and some alien fish distributions were revealed in contrast with earlier known data. Canonical correspondence analysis (CCA) was used to study the relationships between habitat characteristics and species abundance. Water mineralization and maximal observed water temperatures were estimated as the main environmental variables in fish distribution at the local scale. Habitat change leads to fish fauna homogenization as a result of rare species extinction and alien penetration. Growing human population and poor water management make the future of the indigenous fishes unpredictable. [ABSTRACT FROM AUTHOR]

Knowledge of the composition of the gut microbiota in freshwater fish living in their natural habitat has taxonomic and ecological importance. Few reports have been produced on the composition of the gut microbiota and on the presence of LAB in the intestines of freshwater fish that inhabit river environments. In this study, we investigated the LAB community that was present in the gastrointestinal tract (GIT) of Mediterranean trout (Salmo macrostigma) that colonized the Biferno and Volturno rivers of the Molise region (Italy). The partial 16S rRNA gene sequences of these strains were determined for the species-level taxonomic placement. The phylogenetic analysis revealed that the isolated LABs belonged to seven genera (Carnobacterium, Enterococcus, Lactobacillus, Lactiplantibacillus, Vagococcus, Lactococcus, and Weissella). The study of the enzymatic activities showed that these LABs could contribute to the breakdown of polysaccharides, proteins, and lipids. In future studies, a greater understanding of how the LABs act against pathogens and trigger the fish immune response may provide practical means to engineer the indigenous fish microbiome and enhance disease control and fish health. [ABSTRACT FROM AUTHOR]

• Ensemble species distribution modelling was done for freshwater fish. • Occurrence records of small freshwater fish Amblypharyngodon mola were used. • Climatic, topographic, landcover and soil variables were used as predictors. • Upstream precipitation, soil pH and elevation were found to be the key indicators. • Ganges delta region was found to be most suitable habitat. The key challenge in the fields of conservation and resource management is to track local, regional and global species extinctions and preserve biodiversity through optimization of investment of funds. To fulfil that purpose modelling and mapping habitat suitability of species is becoming essential. The freshwater ecosystem is today one of the most threatened ecosystems and fishes are especially vulnerable for climate change as they have fewer choices for dispersal. The altered thermal regimes, land use and hydrology together cause isolation, fragmentation and changes in distributional patterns of fish. In such landlocked situation, there is utmost need to identify suitable environmental conditions for a species to exist. Indigenous fish is one of the essential components of healthy inland aquatic ecosystems as they fulfil several important ecological functions and form an important part of the aquatic food web. Amblypharyngodon mola is an economically and ecologically important indigenous freshwater fish species of the tropical and subtropical floodplain rivers and wetland habitats of India and Bangladesh. However, lack of knowledge about the key environmental indicators is hindering appropriate management and conservation initiation. Modelling and mapping the distribution of A. mola was done for identifying the key environmental variables and predicting the potential distribution area of the species in current climatic condition. The species occurrence data were accessed from both primary and secondary sources and used after cleaning and removing biasness. Climatic, topographic, landcover and soil variables of 1 km resolution were used as environmental predictors. India and Bangladesh together were used as model background. Ensemble species distribution modelling was done, and the model was validated by area under the curve (AUC) value (>0.7). The result showed that the Ganges delta of lower reach going through West Bengal and Bangladesh is most suitable for A. mola occurrence. Annual upstream precipitation (hydroclim_12), soil pH in water (soil_average_02) and elevation (ele_01) are the key indicators for predicting the habitats suggesting the importance of hydroclimatic, topographic and soil variables in determining the distribution of the fish. [ABSTRACT FROM AUTHOR]