Conservation status of freshwater fishes reported from Tungabhadra Reservoir, Karnataka, India

: Fishes constitute the major biomass of the aquatic ecosystem. The economy of the aquatic habitats is chiefly composed of fishes, crustaceans and molluscs inhabiting the given ecosystem. In the present investigation, an attempt was made to study the conservation status of the fishes that are naturally occurring in the Tungabhadra Reservoir located at Hospet, Vijayanagara district of Karnataka. The survey was spread across 12 months from June 2018 to May 2019. A total of 76 species, belonging to 50 genera and 20 families were recorded. As per the latest IUCN Red List, six Endangered, six Vulnerable, four Near Threatened, five Data Deficient and fifty four Least Concern fishes inhabit in TBR.

For Focus, Scope, Aims, and Policies, visit https://threatenedtaxa.org/index.php/JoTT/aims_scopeFor Article Submission Guidelines, visit https://threatenedtaxa.org/index.php/JoTT/about/submissionsFor Policies against Scientific Misconduct, visit https://threatenedtaxa.org/index.php/JoTT/policies_variousIndia is endowed with vast aquatic resources possessing ecological heritage and rich biodiversity.Fishes inhabiting freshwater habitat are profoundly affected due to reduction in water flow, over fishing and increased water pollution.In order to maintain a healthy population of reservoir fisheries it is necessary to monitor water quality parameters, lake hydrobiology, periodic bioassay, and other environmental variables influencing the fish community (CIFRI 2008).Although, Tungabhadra Reservoir (TBR) is subjected to comprehensive fisheries studies, yet there is limited information available on fishes in the reservoir (Rao & Govind 1964;David et al. 1969;Govind 1969;Banerjee & Ray 1979).The TBR is located at 76.333 0 E & 15.300 0 N on the river Tungabhadra.It is one of the largest contributors of the river Krishna with an annual discharge of approximately 14,700 million m 3 of water at its confluence point, which holds 498m at the full reservoir level.It has an average water spread area of about 23,500 ha.The reservoir is located in northeastern Karnataka state and it supplies water to the neighbouring states.The reservoir produced 24 tonnes of fish in 1954-55 to 4,200 tonnes in 1981-82 to 25,638 metric tonnes in 2004-05.Carp seeds (Catla, Rohu and Fimbriatus) are nursed in the neighbouring fish seed farm and stocked at the rate of 4-5 million/ ha until the larvae reach the fingerling size.These 70-80 mm fingerlings are stocked in the reservoir to enhance carp production.
Considering its fish diversity, a study was carried out between June 2018 and May 2019 to document fishes of TBR.The aim of this study is to understand fish diversity and explore their conservation status.

Materials and methods
The Tungabhadra Reservoir has many fish landing centres all along its periphery (Image 1).The fishes are caught using gill nets, cast nets, drag nets and giant alivi SHORT COMMUNICATION J TT seine net.The fish samples hauled during the catch at the two landing centres S-1 and S-2 in the zone-IV deep (Image 1) were collected and identified on site and others were brought to the laboratory for identification using the available taxonomic literatures (Day 1958;Jhingran 1991;Jayaram 2010) and open access fish base website (www.fishbase.organd Eschmeyer's Catalog of Fishes).Local fishermen and the faculty of the Zoology Department, Kuvempu University, Shankaraghatta and Vijayanagara Sri Krishnadevaraya University, Ballari were also consulted for fish species confirmation.

Results and Discussion
In the present investigation seventy six fishes belonging to 20 families were recorded from the reservoir.Among the recorded species, 40 species of fishes were represented from Cyprinidae family, five from Bagridae, four from Danionidae, three each from   2).It also includes exotic species which are not evaluated.Details of the present conservation status of fishes inhabiting TBR are given in Table 1.

Conclusion
In the present study 76 species of freshwater fishes were recorded.As per the recent IUCN Red List, the conservation status of the fishes showed six Endangered, five Vulnerable, four Near Threatened, and five Data Deficient.Commercially important species were being reduced in certain landing centers along left flank of TBR and alien species were occupying the native species niches.To monitor the continuous potential fish yield of the reservoir, adequate release of carp seeds, utilizing the other vacant niches, monitoring the illegal fishing activities along the reservoir and continuous annual documentation of fish catches is necessary.

Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2022 | 14(8): 21704-21709 Freshwater fishes of Tungabhadra Reservoir Nagabhushan 21708 J TT Figure 2. IUCN Red List status of fishes in Tungabhadra Reservoir during 2018-19. Figure 1. Family-wise species composition of fishes from Tungabhadra Reservoir.
Kumar et al. (2006)ere recorded from all landing centers across the study period.The order of abundance of fishes was major carps > minor carps > cat fishes > small fishes.Kumar et al. (2006)observed a similar fish abundance trend in Geralsud Reservoir, Ranchi.As per the latest IUCN Red List, six Endangered, six Vulnerable, four Near Threatened, five Data Deficient, and 54 Least Concern (Figure Species compositionattu, Mastacembelus armatus, Bagarius bagarius, Osteobrama vigorsii, and