Fish diversity

Abstract: Freshwater ecosystems of Nashik district represent the headwaters of the Godavari River and support a diverse assemblage of freshwater fishes. The region contains several important aquatic habitats including rivers, reservoirs, dams, and wetlands that collectively sustain inland fisheries and regional biodiversity. The present review synthesizes ichthyological studies conducted between 1992 and 2024 to establish a consolidated checklist of freshwater fishes and to evaluate ecological factors influencing community structure. The analysis confirms the occurrence of 42 freshwater fish species belonging to 14 families and six orders. The family Cyprinidae represents the dominant taxonomic group contributing nearly 47.6% of total species richness, indicating strong ecological adaptability in riverine and reservoir ecosystems. Spatial comparison of aquatic habitats reveals that relatively undisturbed river systems such as the Darna River maintain higher ecological diversity (H' ≈ 2.45), whereas urban-impacted stretches of the Godavari River exhibit reduced diversity indices (H' ≈ 1.82). Reservoir ecosystems such as Girna and Chankapur dams support moderate species richness but are dominated by stocked carp species and exotic fishes. Approximately 14.3% of the ichthyofauna consists of introduced or invasive species, including Cyprinus carpio,Clarias gariepinus, and Oreochromis niloticus,which may alter native community structure. Environmental modification, particularly reservoir construction and water pollution, has resulted in habitat transformation and increased ecological stress on indigenous fish populations. The review highlights the need for integrated biodiversity monitoring, conservation planning, and sustainable fisheries management to preserve the ecological integrity of freshwater ecosystems in Nashik district. Keywords: Freshwater fish diversity; Cyprinidae; Ichthyofauna; Nashik district; Biodiversity

Komadugu Yobe River is a vital freshwater ecosystem in NorthEastern Nigeria, supporting the livelihoods of thousands of fishermen and contributing significantly to regional food security. Despite its economic importance, comprehensive data on fish species composition, abundance, distribution, and water quality parameters along the river's full length have been lacking hence informed this study. Ten sampling locations were established at 20 km intervals along the river from upstream to downstream. Monthly data collection was conducted over a 12-month period. Fish were captured using different fishing gears appropriate for different water depths and foraging behaviors. Water quality parameters were measured onsite and through laboratory analyses following standard methods. Fish species were identified using taxonomic keys, enumerated, and weighed. Data were analyzed using ANOVA, diversity indices (Shannon-Weiner and Simpson), and percentage abundance calculations. A total of 260,674 individual fish (biomass: 80,643.04 kg) belonging to 13 families and 29 species were recorded. Cichlidae and Mormyridae were the most speciesrich families (5 species each). Shannon-Weiner diversity index (H'=2.19) and Simpson diversity index (D=0.80) indicated high species diversity. Alestes nurse dominated numerically (17.89%), while Clarias gariepinus contributed the highest biomass (13.45%). Water quality parameters remained within optimal ranges for tropical fish species with no significant spatial variations (P>0.05). The Komadugu Yobe River supports a diverse and evenly distributed fish community, attributable to stable and favorable physicochemical conditions throughout its length. Three species (Barilius senegalensis, Clarias spp., and Tetraodon fahaka) showed evidence of decline and require conservation attention. These findings provide essential baseline data for sustainable fisheries management and biodiversity conservation in the region.

The present study assesses the ichthyofaunal diversity and ecological integrity of the Rani Duduma hill stream in the Eastern Ghats of Odisha, India. Spanning five years (2017–2022), the investigation recorded 23 fish species across four orders, with Cypriniformes (74%) exhibiting the highest taxonomic richness. The fish community comprised both torrential specialists (34.78%) and plain water forms (78.26%), indicating a diverse microhabitat structure. Spatial analysis revealed that Station 1 served as a biodiversity hotspot, yielding the highest Shannon’s diversity index (H- =2.41) and Margalef ’s richness index (R=3.17). Physico-chemical analysis confirmed that water quality remains within permissible limits for aquatic life, with heavy metal concentrations falling below critical thresholds. However, the consistent relative abundance of the exotic Poecilia reticulata—maintaining a year-round foothold—suggests competitive pressure on rarer indigenous taxa. Cluster analysis demonstrated significant faunal divergence between lower and upper stream reaches, likely driven by seasonal fluctuations in water velocity and depth (p<0.01). These findings underscore Rani Duduma’s status as a vital lotic ecosystem and highlight the urgent need for conservation strategies to mitigate the impact of invasive species and preserve regional genetic repositories.

Butis bargabhimae sp. nov. is morphologically similar to B. koilomatodon and B. delagoensis but can be distinguished from both of these morphologically by the presence of interorbital scales (IOS 2-3/7-8/2-3), auxiliary scales, bands on the pectoral fin, and the absence of a row of alternating blackish and yellowish spots at the base of the caudal fin. The NCBI BLAST result of COI gene shows 86% similarity with both B. koilomatodon and B. delagoensis. The COI sequence MN171371.1 submitted as B. koilomatodon from Bangladesh shows 99% similarity with B. bargabhimae sp. nov. and belongs to the same clade rather than the clade of B. koilomatodon from the state of Kerala in India and those from other countries. It seems B. koilomatodon from Bangladesh is a misidentification and should be included under B. bargabhimae sp. nov. Likewise COI sequence of B. koilomatodon, as reported earlier by Pahari et al. (2024), suggests this was a misidentification and should be redesignated as B. delagoensis.

Present study consists the species diversity, abundance and community structure of ichthyofauna in the seagrass meadow of Minicoy Atoll, Lakshadweep Islands. Two hundred and three species of fishes were recorded during the study, from four stations in the Atoll. They belonged to 2 classes, 11orders, 43 families and 93 genera. Six species belonged to the class Chondreichthyes and 197 species to Osteichthyes. Family Pomacentridae showed maximum abundance of species (22%). Station I, having close proximity to the coral reefs, observed the maximum number of families (37) and species (129) and that with minimum number was in station II (23 families and 52 species). Bray-Curtis similarity plot showed a similarity range of 22 to 52%, seasonally. Station I showed highest Shannon-Wiener diversity index (H'log 2) (4.22) during August and the lowest (2.91) during June. Stations I and III showed comparatively higher abundance and diversity of fishes. Variability in seagrass habitat structure and the interaction with coral reefs influenced the species composition and diversity of fishes in Minicoy Atoll. The findings of the present investigation can be used as baseline information for the fishery resource management of the region.

In total, 28 of the 29 fish species reported from the Lake Kivu basin occur in the littoral zone of the lake, but information about their structure, occurrence, and the habitats affecting their distribution is largely lacking. The lake’s inshore area is poorly heterogenous, with rock and macrophyte habitats representing the major habitats. The lack of heterogeneity in the habitats is probably an important factor influencing species richness, abundance, and the association between the species and habitats. We evaluated the fish diversity, abundance, and habitat parameters across 14 sites representing the major habitats of the lake, using data collected between April 2018 and October 2019. We calculated Hull and Jaccard indices and applied uni- and multivariate statistical approaches to the collected data. We identified 18 fish species in the lake. In the north, 17 species were found, with high abundance in rocky sites but low abundance in sandy habitats. In the south, 15 species were...

Biota at any place is the product of evolutionary and biogeographic process, which means that the resident biota at any site varies
according to the geographic region as well as in evolutionary time. Though, there are some records of fish diversity in the rivers Rapti
and Narayani which flow through Chitwan National Park, this work updates the record incorporating the variations caused by time and the fishing gear. The first set of sampling was done using a backpack electrofishing gear between 2003 February to 2004 January and the second set was done in April –May 2007 using locally prepared nets and traps through the professional fishermen. 32 species of fish were captured from Narayani river in both the sampling, though with different assemblage and the fish diversity in Rapti river had much difference with 30 species in the first sampling using electric gear and 23 from the second using the local gear. Nevertheless, the compilation of the two gives more or less complete and latest fish diversity of those rivers and this information could be used for
many purposes.
Key words: fish assemblage, Chitwan National Park, temporal variation, fishing gear, record update.

The spatial and temporal diversity of fish assemblage in Indrawati sub-basin was investigated during December 2011 to August 2012. In addition, physico-chemical parameters and spawning grounds to find out the fish hotspots were studied. Altogether 10 sampling sites were selected within the sub-basin, four sites in the main stretch of Indrawati River and six in its tributaries. Two sampling seasons were chosen to study the temporal (seasonal) distribution of the fish assemblages, viz., winter and summer.
The physico-chemical parameters in the study area were suitable for the survival of aquatic biota in the hill streams, including fish. Most of the sites were provided with good breeding habitat conditions for hill stream fishes that include rocks, boulders, cobbles and pebbles. This is indicated by the fact that Schizothorax richardsonii was recorded from all the sampling sites. Therefore, this species was regarded as key-note species in Indrawati sub-basin.
Altogether 19 fish species belonging to 14 genera and 6 species were recorded during the study period. The fish species were most abundant (based on catch per unit effort, CPUE) in Dhadkhola, the Indrawati and Indrawati-Dolalghat compared to the other parts of the Indrawati sub-basin. The highest numbers of fish species (species richness) were recorded in Indrawati-Dolalghat and the second highest in Melamchi Bazaar. This is an indication that the species richness was highest in the main stretch of the Indrawati River compared to its tributaries. The pooled data showed that the fish abundance was greater during the winter season compared to the summer.
Total fish abundance of fish species, based on CPUE, in the Indrawati sub-basin was 34.67 fish per 10 minutes. The most abundant fish species in the sub-basin were Barilius barila and Schizothorax richardsonii followed by Neolissochilus hexagonolepis, Devario aequipinnatus and Schistura beavani.
The main human pressures in the sub-basin related to fish diversity were use of poisons for fishing by the locals and establishment of crusher industries. However, the study of their impacts on the fishery resources in the area has not been carried out before; and should be monitored regularly for proper management of the riverine ecosystem.

Data on fish diversity in shallow marine hydrothermal areas of Indonesian waters are relatively limited. Underwater hydrothermal activity signifies active geothermal processes, where emitted fluids are known for their high temperatures. This study investigates the composition, relative abundance, and diversity of fish species in the non-volcanic hydrothermal zone of the shallow sea waters of Kolono Bay, Southeast Sulawesi. This research was conducted from March to August 2022, using a purposive sampling method. A total of 66 species were identified, belonging to 35 genera, 18 families, and 8 orders. The highest species composition was found in the families Lutjanidae and Scaridae at station I (17.40% and 17.39%, respectivelly), Lutjanidae at station II (20.60%), and Mullidae at Station III (21.74%). Bigeye snapper, Lutjanus lutjanus was the dominant species in the hydrothermal center (47.49%), while species from the genera Chaetodon, Heniochus, Parachaetodon, Coradion, Inegocia, and Zanclus were the least abundant (0.15% each). The diversity index (H' = 2.461-2.922) indicated moderate diversity, with relatively good stability, productivity, and balanced ecosystem conditions. The uniformity index was high (E = 0.643-0.932), while the dominance index was low (C = 0.064-0.239), reflecting an even distribution of species with no clear dominance. The bigeye snapper, a species of reef fish, has demonstrated strong tolerance in both the central and border areas of these hydrothermal zones. This tolerance is evident from the higher abundance of individuals compared to other fish species from the same genus and habitat.

This comprehensive study examined the diversity, abundance, and richness of freshwater fish species in Maroda Reservoir, Chhattisgarh, through monthly sampling conducted from August 2024 to April 2025 across three designated sites. The investigation documented 23 fish species representing 9 orders and 11 families, with Cypriniformes emerging as the dominant order containing 11 species, followed by Siluriformes with 5 species. Multiple diversity indices were calculated, including Simpson's Dominance Index, Shannon-Weiner Index, and Simpson's Index of Diversity to quantitatively assess fish community structure. Concurrent water quality monitoring measured critical parameters, including temperature, pH, electrical conductivity, dissolved oxygen, biochemical oxygen demand, hardness, chloride, nitrate, and phosphate concentrations across seasonal variations. Results demonstrated that physicochemical conditions remained within acceptable ranges for supporting diverse fish populations. However, the reservoir ecosystem faces Original Research Article

Background: The fishes of genus Garra are one of the most abundant and taxonomically confusing groups which requires further studies to evaluate their taxonomical ambiguity. Therefore, the present investigation was conducted on the genus to understand their detailed morphometric and meristic features. Methods: A total of 122 fish specimens belonging to 10 species were collected from the hill stream rivers of Arunachal Pradesh. Eleven morphometric and six meristic parameters were applied for each fish specimen. Identification key was developed after the detailed examination of morphological features. Fin formula was also generated for each species by counting the meristic characters. Phylogenetic tree was developed using morphological characters to understand the evolutionary relationship among the species. Result: Present study observed the maximum length (54.8-135.0 mm) in G. annandalei and minimum length (64.1-70.2 mm) in G. rufa. And this study also confirmed the presence or absence of lobes and tubercles, rostral cap, proboscis, gular disc and fins' shape as key identifying features. Constant in morphometric measurements and meristic counts reveals the uniqueness of the species which was noticed from the generation of fin formula. Further, species were assigned with latest IUCN Red data, G. rupecula was identified as NT, 3 species were under NE and 6 species in LC category. Analysis of phylogenetic tree through neighborjoining (NJ) clustering method with bootstraps 100 depicts that G. lissorhynchus, G. rufa and G. rupecula were belonged to the common ancestral group and G. annandalei and G. quadratirostris were distantly related to G. arunachalensis and G. lamta. A strong positive and linear LLRs were found in between TL and other morphometric characters with r value 0.765. SL showed significantly (p<0.01) higher correlation with TL in all the species.

This study aims to determine: (1) the total size of the length and weight of catch ; (2) Position of catch; (3) The dominant size of lunta selection; (4) Lunta selectivity on types of catches; (5) Pocket dimensions formed and correlation with total length; (6) The maximum length of the middle pocket slice arc; (7) The highest and lowest selection values. Research location in Hulu Sungai Selatan Regency. Data analysis uses experimental fishing, simulation, selectivity values. The results showed that the total length ranged from 8.6 cm -32.5 cm and the weight of fish ranged from 8 grams -260 grams (mesh size =3,2 cm), and the total length ranged from 8.9 cm -28.5 cm and the weight of fish ranges from 10 grams -195 grams (mesh size = 4.3 cm). The position of catch on the lunta is gilled, entangled,and pocketed (mesh size=3.2 cm); entangled and pocketed (mesh size=4,3 cm). The dominant selected fish size is 9.0 cm -9.9 cm (mesh size = 3.2 cm); size 13 cm -13.6 cm (mesh size = 4.3 cm). The most dominant type of fish is Three spot gourami (mesh size = 3.2 cm); and Siamese gourami, (mesh size = 4.3 cm). Value of the correlation coefficient (r) on the lunta, both are = 0, meaning there is no linear relationship between the total length of the fish and the height of the pocket. The maximum length of the middle pocket slice arc is lunta mesh size 3.2 cm and 4.3 cm is 38 cm and 39 cm. The highest selection value for lunta mesh size = 3.2 cm is 0.9998 and the lowest is 0.3851, while the selection value of lunta mesh size = 4.3 cm is the highest 0.992 and the lowest is 0.017.

The diversity of fishes in Gandak river near Sonpur, Bihar, India was studied for a period of 12 month from August 2019 to Septemebr 2020. A stretch of 8 km of Gandak River revealed the ichthyofaunal diversity, assemblage structure, and distribution pattern, and threat status, ornamental and commercially important fishes. Gandak river ecosystem inhabits several aquatic organisms. Change in water quality due to pollution put the fish fauna under stress. Loss of fish species diversity used as an indicator of environmental degradation. This contribution focuses on the diversity of fish population and their conservation aspects in Gandak river ecosystem, Sonpur, Bihar, India. The study revealed the occurrence of 32 species of fishes.

Fish assemblage patterns in Taabo Reservoir, a hydroelectric lake of Ivory Coast, were studied and related to the longitudinal gradient (river-dam gradient) composed of riverine, transitional, and lacustrine zones. Data were collected at 5 stations and each one was sampled during 5 surveys. Fish community structure was analysed using alpha and beta diversity indices. In total, 53 fish species were obtained in the whole ecosystem. Total species richness recorded at each ecological zone was 42, 43 and 45 species respectively in the riverine, transitional and lacustrine zones. Alpha diversity did not differed significantly along the longitudinal gradient but reached the highest value (33 species) in the transitional zone and the lowest (18 species) occurred in both the riverine and lacustrine zones. Temporal variability of Alpha diversity according to the hydrological regime of the lake differed with the zone. Beta diversity showed that fish assemblages similarity was higher between the transitional and the riverine zones (â w = 0.43) and lower between the riverine and the lacustrine zones (â w = 0.79).

This study delves into how local communities engage in the management of Tanguar Haor, a vital wetland in northeastern Bangladesh designated as an Ecologically Critical Area (ECA) and a Ramsar site. The study looks at relationships between important socioeconomic factors like income, education, age, gender, and local participation in wetland governance using household-level data from twelve villages. Employing a mixed-methods approach, the study integrates quantitative household survey data with qualitative interviews and focus group discussions to capture both statistical trends and community perceptions regarding participation in wetland governance. Roles in decision-making, project implementation, evaluation, and benefit-sharing procedures are among them. In contrast to their mainland counterparts in the Sunamganj district, the Tanguar Haor region, which has been inhabited for generations, is home to communities primarily impoverished and socioeconomically marginalized. The degree of meaningful participation is nonetheless unequal and frequently limited by structural inequities, despite the government's efforts to promote a co-management model incorporating governmental actors and local communities. The study finds that while the most underprivileged groups continue to be under-represented, those with greater socioeconomic status are substantially more involved in wetland management. These results emphasise how crucial it is to address socioeconomic inequality in order to promote inclusive and sustainable wetland governance. The study contributes to the broader discourse on environmental justice, local stewardship, and the role of equity in natural resource management.

Ichthyofaunal diversity in Laguna Hule, Costa Rica. Laguna Hule is a volcanic origin crater which has been flooded over time, resulting in a deep mass of water with no previous studies about its fish community. For five months we sampled it and a draining stream (Pata de Gallo) with nets, and hook and line. The captured specimens were identified in situ to the possible lowest taxonomic level. The lagoon mostly had species normally found near aquatic vegetation: Amatitlania siquia, Amphilophus alfari, Astyanax aeneus, Cynodonichthys sp., Parachromis dovii, Phallichthys amates and Poecilia gillii (dominant: A. aeneus, P. gillii and P. amates). The stream was dominated by Brachyrhaphis olomina but also had Rhamdia laticauda. The low diversity indices (1,48 in the lagoon and 0,26 in the stream) are characteristic of lacustrine ecosystems. Females were, as expected, larger and more abundant in P. amates and B. olomina; whereas in P. gilli, some males were larger. The area is affected by pollution, introduction of invasive species, uncontrolled fishing and use of destructive fishing gear. We propose demarcation of site protection status and organizing a community group to protect this fish community.

The occurrence of Lagocephalus inermis (Temminck & Schlegel, 1850) is reported for the first time from Digha extending the range of the species to the east coast of India based on one specimen. This species was already reported from southeastern coast of India and western coast of India. The 196 mm standard length specimen from Digha Mohana is described in detail.

The aim of the present study was to assess and compare the nutritional quality of sun dried fishes and oven dried fishes during July 2016 to December 2016. Five fish species (C. punctatus, M. cavasius, M. pancalus, C. striatus and W. attu) were collected from the Chalan beel area and brought into the laboratory of Department of Fisheries of University of Rajshahi. All species were processed and dried by the sun rays and in the oven (105°C) for different hours depending on the different species. Then the nutritional analyses were done by using standard method. The highest lipid content was found in oven dried W. attu (11.32±0.30%) and the lowest was found in sun dried C. striatus (5.48±0.70%). The highest protein content was found in oven dried M. pancalus (77.12±0.36%) and the lowest was found in sun dried M. cavasius (55.38±0.67%). The ash content was varied from 4.34±0.23% (oven dried M. pancalus) to 18.43±0.77% (oven dried M. cavasius). The highest moisture content was observed in sun dried C. punctatus (13.07±0.57%) and the lowest was observed in oven dried M. cavasius (6.25±0.24%). Calcium content was varied from 5.34±0.36 mg/100g (sun dried M. cavasius) to 29.31±0.47 mg/100g (oven dried C. punctatus). Iron content was ranged from 0.82±0.00 mg/100g (sun dried M. cavasius) to 2.82±0.04 mg/100g (oven dried W. attu). No significant difference was found between the sun and oven dried fishes for proximate composition (lipid, protein, ash and moisture) and mineral contents (calcium and iron).

The present investigation is a humble attempt to explore fishing techniques of the River Baral from November 2010 to May 2011. Different fish capture methods, fishing gears and crafts that were usually used in the study area have been provided. Hand fishing, cloth fishing, bait fishing and fishing by dewatering were also observed. Causes of habitat degradation and changes of natural habitat and declination of fishes were also observed. Some problems of the fishing community of the study area were also identified. A few policy recommendations have been given in the concluding chapter which may have some positive implication on the life and living of the fishermen in Bangladesh in general and the Baral basin in particular.

In order to avoid the seasonality and the cryptic fishes disadvantages, data and photographs taken between 2011 and 2013 were obtained by the second author and confirmed with other local divers living on the island yearround. Discussions with long time island residents, and sharing of the photos on social media sites from the island, were also used to confirm observations and biotopes. Supplemental information on the observed species were also provided by the second author (>2,000 dives around the island over 7 years). Species were identified and checked through the use of various taxonomic literatures and pictorial guide books,

Sisorid catfish of the genus Glyptothorax are widely distributed, with as many as 40 nominal species reported from India, where they typically inhabit fast-flowing hill streams and faster flowing stretches of larger rivers and streams. We recorded new biogeographical distribution of three species of Glyptothorax from the tributaries of northern plains in the Ganges basin. The specimens were collected during experimental fishing for biodiversity studies using cast nets (2010-2012). While G. conirostris were collected from the Ganges canal, G. cavia and G. telchitta were captured from the river Gomti. Previous descriptions were based on preserved specimens; we present diagnostic features and an illustrated redescription based on fresh specimens.

The River Mahananda, a tributary of the Ganga, sustains rich fish biodiversity crucial for the livelihoods and food security of local communities in Katihar, Bihar. There were 61 species in all, including native, food, sport, and decorative fishes, spread throughout 46 genera, 21 families, and 7 orders. According to trophic guild analysis, carnivores predominated, followed by herbivores, detritivores, and omnivores, indicating ecological equilibrium. Sanctuary stretches had better species richness (Shannon-Wiener Index, H = 2.50-2.53) than non-sanctuary zones, demonstrating the importance of protected regions for conservation. Relative abundance analysis revealed that economically significant species including Labeo rohita, Mystus cavasius, and Clupisoma garua were more prevalent. However, overfishing, destructive gear, sand mining, agricultural runoff, household pollutants, and habitat fragmentation pose serious risks to fish diversity. Numerous endangered and near-threatened species have declined as a result of these stresses, calling for immediate conservation action. It is essential to fortify fish sanctuaries, control fishing methods, restore habitats, and encourage community-based co-management. Ecological stability also depends on habitat connectivity and pollution control. The Mahananda River's ichthyological richness must be preserved for the region's socioeconomic stability as well as ecological health.

Freshwater ichthyofauna play a vital role in biodiversity, nutrition, and rural livelihoods in tribaldominated regions of eastern India. The present study documents fish diversity and market dynamics across Santhal Pargana, Jharkhand, with emphasis on the Mayurakshi and Basloi river systems and linkages with the Ganga River at Saheb Ganj. Using market surveys, GPS-tagged site observations, and vendor interviews, eight fish taxa belonging to five families were recorded from Ramgarh Bazaar, Karudih Hatia, Dumka Hatia, and adjoining rivers during August 2025. Species were classified into exotic aquaculture fishes (Pangasius, Roopchand, Golden carp), Indian major carp (Rohu), small indigenous species (SIS) (Poti, Maria, Jhal), and indigenous catfish (Magur). Market prices varied widely: exotic fishes were cheaper (₹140-160/kg), SIS fetched premium rates (₹200-250/kg), while carps and Magur were intermediate (₹150-180/kg). Results indicate an ecological-economic duality: bulk fish supply is dependent on aquaculture imports from Andhra Pradesh and West Bengal, while riverine SIS continue to sustain cultural diets but are threatened by juvenile overharvest and habitat stress. The findings highlight the need for integrated conservation strategies, regulation of juvenile harvests, and promotion of SIS aquaculture to strengthen biodiversity and nutrition in Santhal Pargana.

It is a fish sampling site at River Mahananda near Siliguri with geographical position 26°43'N and 88°25'E. Station 2 : Fish fauna of river Balason were sampled near Matigarah village with geographical position 26°41'N and 88°24'E. Station 3 : Mechi river originates from the hills of the border of Nepal. Our sampling was done from this river near Naxalbari (26°44'N and 88°25'E). Station 4 : Fish sampling from river Teesta was done near Teesta Bazar of Kalimpong (27°54'N and 88°25'E). Station 5 : Fulbari Barrage on river Mahananda was chosen as fish sampling site (26°38'N and 88°24'E). It is situated at the border between Darjeeling and Jalpaiguri district where water of River Teesta is channelized to river Mahananda as a part of the Teesta River Valley Project. The D:ZSI\(Rec-'09)-109 Fol\Rec-109(1)-49\(M-2)\16 CD

India is well-known for its abundant and varied fish species, a result of its great variety of aquatic environments. The earliest reference to fishes in Indian writing is found in Vedas and Puranas. The taxonomic knowledge on the fishes of India started with the father of taxonomy, Linnaeus in 1758, whose works included many fishes from Indian waters, although others are mistakenly tagged as 'Habitat in India'. For this review, a total of 958 articles in the literature were used. The compilation of records and resulting analysis of the ichthyofauna of India yielded a total of 3,967 species of fishes belonging to 1,197 genera, 287 families, and 60 orders. Among the various states, Tamilnadu had the highest fish diversity with 1,919 species followed by the Andaman and Nicobar Islands with 1,544 species, and Kerala with 1,202 species. Of the 3,967 species, 2,173 species occur exclusively in marine

The aim of the study was to explore the fish fauna of Atal Sagar Dam in Shivpuri district Madhya Pradesh.The study was conducted during Feb 2018 to Jan 2019. Fish diversity was assessed by calculating the various diversity indices such as Shannon Weiner index (H), Simpson Dominance Index (D), Simpson index of diversity (1-D), Gibson's Evenness (E) and Margalef index of species richness. The survey indicated that the fish fauna of Atal Sagar Dam consists of 22 species belonging to 6 order and 11family Out of them Cypriniformes order is the most dominant group with recorded 10 species, Siluriformes consists of 5species,Perciformes 4 species, Osteoglossiformes consist 1 species, Beloniformes followed1species, Synbranchiformes consist1species during studyShannon-Weiner diversity index of five different sampling sites showed variation and ranged from 2.77 to 1.97.The highest fish diversity was recorded at site 2 and lowest fish diversity at site 4. Maximum species richness was observed in site 2 as compared to other sites of Atal Sagar Dam.

Bangladesh is dominated by vast floodplains with its huge small and large water bodies called haor, baor, beels under wetland system. The water resources system having unique natural setting like intensive river network and floodplains, wetland, bio-diversity, etc. with interdependent interactions has presented us the present social life of Bangladeshi typology. The beel fishery is a vital part of this eco-system and economy related with water. These water resources have been exploited by a small number of powerful people overriding all values and norms depriving the poor fisheries group. At present, fisheries and environmental degradation of beels and wetlands is alarming in Bangladesh putting severe adverse effects on livelihoods of subsistence fishery group as well as on beel ecosystem i.e. on water resources system. Community Based Resource Management Project is one of the latest such efforts since 2003 in Sunamganj haor area. Education level of the schooling aged children, skill training, sanitation & hygiene awareness, organizational involvement, women mobility, shearing of responsibility, land uses for fisheries activities, land prices, access to alternative resources, improvement of wall materials, access to roads, average yearly income of BUG, access to financial loan and access of women to economic activities has been increased for the during project period compered with pre-project period. Under the marketing channel of study beels (Fishermen -Nikeries -Beparis -Aratdars -Consumers), Fishermen's share was 74% and 70% for Boiragimara and Chatol Udaitara Beel respectively of what was paid by the consumer as the retail price. Production efficiency as labor return distribution, gender equality, impact on biodiversity, beel yield and marketing efficiency are better condition for study beels for during project periods compared with pre-project period. BUG federation development, involvement of LGIs, habitat restoration, permanent sanctuary establishment, post project activities, construction of fish marketing sheds with adequate facilities have been suggested to improve the existing condition. Siltation has been occurred as a product of climate change impacts. Adequate area of the beels would be re-excavated to overcome the problem. Sustainability indicators have been analyzed for few beels and for short duration. Better result would be shown for more beels and for long duration. The outline of the thesis is as follows: Chapter 1 provides the background, objectives and limitations of the study.

Assam is recognized as one of the hotspots of freshwater fish diversity. Biodiversity and its conservation are regarded as one of the major issues of enabling sustainable use of natural resources. A survey was conducted on the Puthimari beel of Barpeta district since June 2017 till Feb-2018. Its geographical location falls under latitude 26º20'11'' N and 90º45'19'' E. Situated on the North of Barpeta district lies the Puthimari beel, which falls under Barnagar revenue circle. The beel is almost 2 km far from Sorbhog town. Primary data were collected by visiting the studied area twice a month. The local people and fishermans have been questioned and interviewed. The total area of the wetland was recorded to be 300 ha. The present investigation reveals an ichthyofaunal diversity of 46 indigenous fish species belonging to 37 Genera, 8 Orders and 19 Families. Among these 5 species are nearly threatened (NT), 01 species vulnerable (VU), 39 species least concern (LC) and 2 Data deficient (DD). Conservation status is evaluated based on IUCN data (2017-2). Order Perciformes was highly dominant representing 07 families. The Cyprinidae family was most diversified family with 16 representative species. This wetland holds numbers of economically important fish species having high market value as live fish many of which have potential value as food and ornamental. Most of the fish species once dominant in the beel are now endangered. If properly managed in scientific lines, these water bodies can play a vital role in boosting rural economy in addition to ground water recharge and flood control. So in this study an attempt has been made to know the actual status of icthyofaunistic resources of the Puthimari beel and its conservation status.

Reservoirs is one of the great sources of fish and contribute significantly to the fish consumed. However, catches from different water bodies have declined over the past few decades partly due to various illegal fishing activities. The study was conducted on Kafin gana reservoir in Birnin Kudu, Jigawa in 2018 to assess fish species composition and abundance in order to provide technical information for sustainable exploitation of fish. Biodiversity indices (Shannon weiner index and Simpson , index of diversity) indicate that the reservoir is diverse. A total of fifteen(15) fish species representing nine(9) families were identified under families Mormyridae,Claridae, Cichlidae, Schilbedae, Mochokidae,Cyprinidae,Bagridae, Protopteridae, and Palaemonoidae during the dry an drainy seasons. The family Cichlidae had the highest representation in terms of species number. Mormyridae hadthe highest relative abundance of (45.89%) during the rainy season and Palaemonoidae had highest relative abundance of (44.94%)during the dry season. Palaemonoidae and Protopteridae were only found during the dry and rainy season respectively. The overall diversity indices of this reservoir fall between moderate with Shannon weiner index of 1.761 to a higher with Simpso's index of 0.803. The Simpso's index indicates that there is 80% chance of randomly picking 2 families that are different. The results of the study revealed the need for management interventions to manage the Kafin gana reservoir.

Fish species abundance, seasonal variation and condition factor (k) was assessed in this study between October 2012 and September 2013. Samples collected from Erinle reservoir were identified and sorted out into species, the morphometric parameters of each sample were measured using a measuring board graduated in cm and weighed using a Mettler balance (P 1210 model). Fulton’s condition factor (k) was calculated using the equation K=100W/L. Fish species identified were twelve: Alestes macrolepidotus , Chromidotilapia guntheri , Oreochromis niloticus , Sarotherodon galilaeus , Tilapia mariae , Tilapia zillii , Clarias gariepinus , Chrysichthys auratus , Hepsetus odoe , Mormyrus rume , Marcusenius senegalensis and Schilbe mystus . The species belong to seven families from a total of 561 fish samples with varying degree of abundance. S. galilaeus had the highest abundance of 55.08% of the total samples collected while C. gariepinus had the lowest abundance of 0.18% as only one sample wa...

Understanding environmental biodiversity drivers in freshwater systems continues to be a fundamental challenge in studies of their fish assemblages. The present study seeks to determine the degree to which landscape variables of Amazonian floodplain lakes influences fish assemblages in these environments. Fish species richness was estimated in 15 Amazonian floodplain lakes during the high and low-water phases and correlated with the areas of four inundated wetland classes: (i) open water, (ii) flooded herbaceous, (iii) flooded shrubs and (iv) flooded forest estimated in different radius circular areas around each sampling site. Data were analyzed using generalized linear models with fish species richness, total and guilds as the dependent variable and estimates of buffered landscape areas as explanatory variables. Our analysis identified the significance of landscape variables in determining the diversity of fish assemblages in Amazonian floodplain lakes. Spatial scale was also iden...

Uncertainities in measurement of Saprobic score and Diversity score were mainly due to substratum composition of Boulders, Cobbles and Pebbles, Size of Gravel ,Sand, Silt and Clay, which ascertained the biological establishment of rare and endangered nymph\ larvae of benthic macro-invertebrates suchas, Iron, Ironodes, Epeorus/Ironopsis and Rithrogena, Oligoneuriella, Kyphopteryx, Leuctra, Perlomiya and Eucapnopsis used for bio-monitoring of water quality of River Bhagirathi in Uttarakhand during year 2004 to 2008. Thus, during winter in November, 2004 when flow velocity and water temperature was lowest, combined uncertainties in Saprobic score was ± 4.7, and Diversity score was ± 0.41 contributed through random sampling during collection of benthic macro-invertebrates from River Bhagirathi at Gangotri. Whereas, during extreme summer of April, May and June, glacial melt water contributed uncertainties in measurement of Saprobic and Diversity score indicating clean water quality of class 'A' of BWQC. Uncertainties increased to ± 7.12 for Saprobic score and ± 0.45 for Diversity score at upstream of Uttarkashi whereas, at Tehri uncertainties were reported ± 5.1 for Saprobic score and ±0.5 for Diversity score consequent upon habitat degradation.

Deep-sea species, although bizarre and odd-looking organisms, also warrant scientific and conservation attention. However, information on their occurrence and fishery throughout their distribution remains limited, hindering the development of effective conservation strategies. This paper contributes to addressing this gap by providing information on the occurrence of Sickle Pomfret Taractichthys steindachneri (Döderlein, 1883) in Palawan waters and notes on pomfret fishery in the Philippines. Two individuals were encountered for sale at the Puerto Princesa City New Public Market on 26 February 2023 and were photographed alongside a size reference. Standard (SL) and total lengths (TL) were measured using CPCe software, revealing significant sizes-538.1 mm SL and 683.6 mm TL for the first individual, and 574.0 mm SL and 741.1 mm TL for the second, exceeding the previously recorded maximum lengths. Molecular sequencing further validated the species' identity. Although seldom observed in the markets, the species are caught in deep trenches of the Sulu and West Philippine seas. In total, eight pomfret species are recorded in the Philippines, however, comprehensive information on the catch volume, fishing grounds, and other biological attributes of these species are needed to promote sustainable utilization and management.

La réussite d'une thèse est le fruit de la contribution de plusieurs personnes et entités. C'est avec une grande sincérité que j'adresse mes plus vifs remerciements et toute ma gratitude envers tous ceux que j'ai croisé le long de ces quatre années de thèse entre Madagascar, La Réunion, France, et Vietnam. Je tiens tout d'abord à adresser mes plus sincères remerciements à mes directeurs de thèse. Dr Dominique PONTON, il me manque le mot pour te remercier. Tu as été plus qu'un encadrant, tu n'as pas compté ton temps, même les week-ends ou jours fériés, pour m'accorder ton soutien sans faille et m'épauler dans les dures épreuves que j'ai vécu au cours de cette thèse. Tes judicieux conseils aussi bien scientifiques que personnels m'ont été d'une grande aide le long de ces quatre années. Tes pertinentes remarques et ta relecture méticuleuse de chacun des chapitres m'ont sans aucun doute permis de préciser mon propos. Merci du fond du coeur pour ta patience, ton écoute, ta disponibilité, et surtout ta réactivité. Dr Jamal MAHAFINA qui m'a non seulement initié à la recherche en tant qu'encadrant lors de mon DEA, mais également m'a encouragé pour que je continue jusqu'au bout cette passionnante recherche dont cette thèse en est l'aboutissement. De plus, malgré ses lourdes occupations, il s'est toujours montré disponible pour me prodiguer ses nombreux conseils de qualité, et m'apporter son aide pour le bon déroulement de cette thèse. J'adresse également mes remerciements : au directeur de l'école doctorale de l'Université de Toliara, qui est aussi le Président du jury, et de l'Université de La Réunion, ainsi qu'aux présidents de ces deux Universités pour avoir donné leurs avis favorables pour que je m'y inscrive et que cette thèse soit en co-tutelle ; et aux membres de mon comité de thèse composé

Les écosystèmes marins qui fournissent de multiples services écosystémiques indispensables au bien-être de l’humanité sont actuellement menacés par la surexploitation des ressources et l’utilisation d’engins destructifs. Ceci conduit à une perte à l’échelle globale de 20% des mangroves, 19% des récifs coralliens et 110 km2 par an des herbiers. Les habitats côtiers qui soutiennent jusqu’à 20% de la production globale de la pêche sont les plus touchés, notamment dans les pays les moins avancés comme Madagascar. Dans ce pays, 87% des écosystèmes récifaux sont menacés, notamment dans le sud-ouest où les petits pêcheurs utilisent des engins prohibés capturant les juvéniles. Une meilleure connaissance de l’écologie des jeunes poissons est donc un point clé pour la mise en place des mesures de gestion efficaces et robustes. D’où l’objet de ce présent travail centré sur les jeunes stades de développement des poissons, identifiés en utilisant le barcoding ADN. Les identifications à l’espèce ...

La réussite d'une thèse est le fruit de la contribution de plusieurs personnes et entités. C'est avec une grande sincérité que j'adresse mes plus vifs remerciements et toute ma gratitude envers tous ceux que j'ai croisé le long de ces quatre années de thèse entre Madagascar, La Réunion, France, et Vietnam. Je tiens tout d'abord à adresser mes plus sincères remerciements à mes directeurs de thèse. Dr Dominique PONTON, il me manque le mot pour te remercier. Tu as été plus qu'un encadrant, tu n'as pas compté ton temps, même les week-ends ou jours fériés, pour m'accorder ton soutien sans faille et m'épauler dans les dures épreuves que j'ai vécu au cours de cette thèse. Tes judicieux conseils aussi bien scientifiques que personnels m'ont été d'une grande aide le long de ces quatre années. Tes pertinentes remarques et ta relecture méticuleuse de chacun des chapitres m'ont sans aucun doute permis de préciser mon propos. Merci du fond du coeur pour ta patience, ton écoute, ta disponibilité, et surtout ta réactivité. Dr Jamal MAHAFINA qui m'a non seulement initié à la recherche en tant qu'encadrant lors de mon DEA, mais également m'a encouragé pour que je continue jusqu'au bout cette passionnante recherche dont cette thèse en est l'aboutissement. De plus, malgré ses lourdes occupations, il s'est toujours montré disponible pour me prodiguer ses nombreux conseils de qualité, et m'apporter son aide pour le bon déroulement de cette thèse. J'adresse également mes remerciements : au directeur de l'école doctorale de l'Université de Toliara, qui est aussi le Président du jury, et de l'Université de La Réunion, ainsi qu'aux présidents de ces deux Universités pour avoir donné leurs avis favorables pour que je m'y inscrive et que cette thèse soit en co-tutelle ; et aux membres de mon comité de thèse composé

The Halda River of Bangladesh has immense importance as it is the only natural spawning ground of major carp fishes. In the present survey, the overall fish distribution and biodiversity from the upper portion of Halda River along with its two tributaries were studied. The sampling stations were Nazirhat Bridge, Sattarghat Bridge and Garduara. Fishes were collected directly from sampling stations two times in a month during the period of January to December, 2012. The species diversity was analyzed using the following diversity indices: Simpson dominance index (D); Simpson index of diversity (1-D); Shannon–Weiner index (H); Evenness index and Margalef index with the help of software PAST (Pale ontological Statistics Software Package for Education and Data Analysis). Totally 4,337 individuals of fish were counted. 63 species belongs to 24 families and 51 genera were recorded. The most abundant family was Cyprinidae, having 817 individuals (18.84%) followed by Gobiidae family with 629...

A new species of Corumbataia is described from Rio Maranhão, Rio Tocantins basin, central Brazil. The new species is distinguished from all congeners by the presence of a small, naked area on snout tip; by having the abdomen covered with small platelets forming a shield which reaches the lateral mid-ventral plates; by the anterior profile of the head rounded in dorsal view; by the lower lip not reaching the transversal line of the pectoral girdle; and by the presence of 28 or 29 vertebrae. High genetic divergence in mitochondrial cytochrome c oxidase subunit I (COI) further supports the validity of this new species. Our phylogenetic analysis shows a derived subclade in Corumbataia, herein named as the Corumbataia cuestae group, composed of the new species plus C. cuestae, C. tocantinensis, C. britskii, C. liliai, and C. lucianoi. This group is defined by having a conspicuous crest of hypertrophied odontodes on head; absence of the adipose fin or a single series of platelets at adipo...

A new species of Corumbataia is described from Rio Maranhão, Rio Tocantins basin, central Brazil. The new species is distinguished from all congeners by the presence of a small, naked area on snout tip; by having the abdomen covered with small platelets forming a shield which reaches the lateral mid-ventral plates; by the anterior profile of the head rounded in dorsal view; by the lower lip not reaching the transversal line of the pectoral girdle; and by the presence of 28 or 29 vertebrae. High genetic divergence in mitochondrial cytochrome c oxidase subunit I (COI) further supports the validity of this new species. Our phylogenetic analysis shows a derived subclade in Corumbataia, herein named as the Corumbataia cuestae group, composed of the new species plus C. cuestae, C. tocantinensis, C. britskii, C. liliai, and C. lucianoi. This group is defined by having a conspicuous crest of hypertrophied odontodes on head; absence of the adipose fin or a single series of platelets at adipo...

The ichthyofaunal diversity from Durgabai Doh Kumbhali Lake, Sakoli, Bhandara, the survey was done for fish diversity. Total of 18 species belonging to 9 orders and 11 families were identified. This was the systematic survey of the fish diversity of this lake. The ichthyofauna includes 18 species, 11 families, and 9 orders. Cypriniformes, with six species (33.3%), is the most prevalent order due to its hardiness and adaptability. Other orders include the Percifomrs and Ophiocephaliformes with two species (11.1%), and all remaining orders Cichliformes, Beloniformes, Mastacembeliformes, Osteoglossiformes, Angulaformes with one species (9.1%). It is proposed that the scientific information on ichthyofaunal diversity and distribution status will surely help in serving the future purposes of sustainable exploitation and concurrent conservation of fish resources. Fishing impacts not only exploited species but also biological and environmental connections to fished species and their habitats.

In order to estimate the diversity of fresh water fish fauna of Pakistan numerous studies have been undertaken. The data presented in this paper was collected at Head Qadirabad and Head Khanki situated at River Chenab, from 2007-09. The data collected in the present study have revealed that the population of carps is decreasing gradually in river Chenab. The Shannon-Weiner Diversity Indices (H&#39;) for carps was calculated and presented in this paper.

Kaptai Lake is the largest artificial reservoir in South-East Asia and very rich in inland open water capture fisheries of Bangladesh. A study was conducted in three different communities viz. Natun Jele Para (mostly Hindus and entirely depends on fishing at lake), Adar Pahar (mostly Muslim and involved in various occupation) and Mitingachori (mostly ethnic group called Chakma, not entirely dependent on the lake fishery) to understand the historic changes of lake fish biodiversity. PRA tools, well-being ranking of the community people, were used to collect data. It was obtained mixed livelihood profiles in three communities but almost similar views on about the biodiversity changes of fishes in lake. About 44 fish species were recorded and ranked in terms of their availability within the last few decades. Indigenous and coastal fish species were available before the embankment (1960). Then some exotic carp species like Chinese carp, Big Head Carp etc. were dominated in the catch com...