A total of 35 piscine species from 28 genera of 18 families and 11 orders were found in the Karingali wetland over the course of the current study. The prominent orders were Cypriniformes, Siluriformes, Perciformes, Anabantiformes, Cichliformes, Beloniformes, Elopiformes Synbranchiformes, Gobiiformes, Clupeiformes and Mugiliformes (Table 1). Horabagridae, Bagridae, Pangasiidae, Heteropneustidae and Siluridae are the families that belongs to the Order Siluriformes which represent more in number, whereas Channidae, Osphronemidae and Anabantidae are the three families recorded for the Order Anabantiformes. Ambassidae and Nandidae, two families in the Order Perciformes, were reported, with the remaining orders having one family each.
Whereas Elopiformes and Clupeiformes were the least frequently reported, the order Cypriniformes were the most numerous. There are more species in the Cyprinidae family. All five study regions reported identifying Channa striata, Anabas testudineus, Xenentodon cancila, Amblypharyngodon melettinus, Rasbora daniconius, Puntius mahecola, Heteropneustes fossilis and Dawkinsia filamentosa. Nevertheless, Nedumpadakam (site-1) were the only place in which
Channa diplogramme,
Pangasinodon hypothalamus,
Megalops cyorinoides and
Stolephorus indicus were identified. Among which,
Amblypharyngodon melettinus and the
Puntius species, which were found in substantial numbers in this wetland, were much more numerous than
Pangasinodon hypothalamus and
Channa micropeltes species.
The only family listed for the order Cypriniformes was Cyprinidae, which has 11 species within 8 genera. The species were
Amblypharyngodon melettinus, Rasbora daniconius, Tor khudree, Puntius euspilurus, Puntius mahecola, Puntius sophore, Dawkinsia filamentosa, Labeo dussumeri, Systomus chryseus, Systomus rufus, Hypselobarbus curmuca.
During the study period, seven species from genus and five families of the order Siluriformes were reported.
Horabagrus brachysoma, Mystus oculatus, Mystus armatus, Pangasinodon hypothalamus, Heteropneustes fossilis, Wallago attu and
Ompok malabaricus are among the species on the list. The least frequently observed species from the Karingali wetland is Pangasinodon hypothalamus, which belongs to this order.
Three species from two genus comprise the Order Perciformes. They were
Parambassis dayi and
Parambassis thomassi from Ambassidae family, Nandus from Nandidae, the order Anabantiformes was represented by 5 species that are members of 3 genera and 3 families.
Pseudosphromenus cupanus from the
Osphronemidae, Channa diplogramme, Channa micropeltes, Channa striata (Channidae),
Anabas testudineus (Anabantidae). The only family identified from the order Cichliformes is Cichlidae. The three species were
Etroplus suratensis, Pseudoentroplus maculatus and
Orechromus niloticus.
Only one species,
Xenentodon cancila of the Belonidae family, comprises the Order Beloniformes. Another solitary species was
Megalops cyorinoides of the Megalopidae family of the order Elopiformes. The other orders that had a single species represented them were (
Macrognathus fasciatus) Gobiiformes (
Glossogobius giuris) Clupeiformes (
Stolephorus indicus) and Mugiliformes (
Mugil cephalus)
.
The percentage composition among various orders reveals that the order Cypriniformes were represented by 42%, Siluriformes 15%, Perciformes 5%, Anabantiformes 12%, Cichliformes 12%, Beloniformes 5%, Elopiformes 1% Synbranchiformes 2%, Gobiiformes 2%, Mugiliformes 3% and Clupeiformes 1% (Fig 2).
Fisheries in India have great potential of contributing to the food security of the country. Reservoirs and lakes are the main resources exploited for inland fisheries and understanding of fish faunal diversity is a major aspect for its development and the sustainability management. Fisheries in India have great potential of contributing to the food security of the country. Reservoirs and lakes are the main resources exploited for inland fisheries and understanding of fish faunal diversity is a major aspect for its development and the sustainability management. Fisheries in India have great potential of contributing to the food security of the country. Reservoirs and lakes are the main resources exploited for inland fisheries and understanding of fish faunal diversity is a major aspect for its development and the sustainability management.
In Karingali wetland, cyprinids have been discovered to be dominant. Additionally,
Das and Nath (1966);
Tilak (1971);
Malhotra and Dutta (1975);
Dutta and Malhotra (1984);
Dutta and Kour (1999);
Dutta (2003);
Johnson and Arunachalam (2010);
Kantaraj et al., (2011); Hoque Rabiul (2023) have reported on the dominance of cyprinids. These three Orders Cypriniformes, Siluriformes are the most prevalent groups in the freshwater bodies hence the findings indicated above are typical
(Rahman, 2005). Due to their high adaptive behaviour and capacity to inhabit the various habitats that are available to them, cyprinids predominate in all research sites.
Nisa et al., 2021). The same point of view has been supported by several researchers
(Gandotra et al., 2015; Wani et al., 2015).
The diversity and abundance of the Karingali Wetland were determined using the Shannon-Weiner, Simpson’s, Margalf, Richness and Eveness indices. The Simpson’s dominance index ranges from 0.04284 to 0.08185 (Table 3). S3 recorded the greatest value and S1 reported the lowest value. The value demonstrates a peak in July and a slow decline in March. Whereas the range of the Shannon-Weiner index value is 2.632 to 3.212 (Table 2). The highest values were from S1 and the lowest values from S3. March marked the Shannon-Weiner index’s peak and July its low point. The lower dominance value suggests that individual species are not quantitatively significant. This trait once again supports the findings of
(Sharma and Sharma, 2008).
Wilhm and Dorris (1968) assert that clean water is specified if the Shannon’s index (H’) value is greater than three. A score between 1 and 3 indicates generally clean water. Because of anthropogenic activity and the discharge of domestic sewage, the study area were at the verge of pollution. The evenness value ranges from 0.7567 (S4)- 0.9818 (S5) (Table 4). Evenness levels peaked in February and declined in July. The Margalaf richness index was peak in S1 at 5.189 and least in S3 at 3.112. (Table 5). March had seen the greatest values, while February had seen the lowest values. In this study, January and February have seen highest number of freshwater fish recorded. Due to the absence of rainfall, the water depth has been lowered to the barest minimum, allowing fisherman to use their fishing gear more efficiently.
Rising water levels during the rainy season in tropical environments with seasonal flood pulses cause fish to travel laterally onto floodplains or longitudinally upstream to spawn and feed. Junk
et al. (1983)
Winemiller and Jepsen (1998). Seasonal rainfall may have had an impact on nutrient inputs, affecting the usage of fish habitat, the availability of food resources and reproductive effort.
Archis and Krik (2018) Overfishing, alien species invasion, uncontrolled water pollution from different sources causes and damaging fishing techniques are considered to be the main concerns to fisheries management in the fresh water (Dinesh
Kumar et al., 2020). The loss in fish variety is caused by habitat destruction, fishing pressure and foreign fish invasion
(Lakra et al., 2008; 2009). In rivers, lakes with river sources and reservoirs, fish populations’ abundance varies greatly from year to year and the relative frequency of various species varies in population. Floods and variations in rainfall have an impact on this change. Spawning, growth and survival rates are improved by the expanding area and flood flow time
(Hashemi, 2015).
Freshwater fish variety is decreasing as a result of the combined and interrelated effects of overfishing, contamination of aquatic environment, altered flow patterns, habitat degradation and exotic species invasion
(Dudgeon, 2006). The increase in polluting inputs, including as industrial effluents, pesticides and fertilisers from aquaculture, agriculture and home sewage, was caused by an expanding population and more intensive land use
(Adikari, 2009). The primary cause of freshwater declining water quality is because of entry of industrial effluents and other pollutants through inflowing drains
(Rao and Rao, 2000; Rao and Shekar, 2003). It has been proposed that foreign species introduced for various reasons could constitute a hazard to the local fish population. Recreational activities and other anthropogenic activities are frequent in this wetland. These techniques will affect the wetland and leads to habitat destruction of fish species. Previous researches about freshwater habitat concurs the same
(Raju and Simachalam, 2014).
According to
Nisa (2021), anthropogenic activities like as fishing pressure, pollution and destroying habitat all have a direct correlation to one another. It is critical to emphasize that sites 1 and 4 have the highest level of anthropogenic activity, such as habitat destruction, runoff from agricultural regions, garbage disposal and exploitation. The least diversity index is justified because fish habitat and water quality are being merely destroyed. The less diverse fish fauna in the wetland may be attributed to habitat degradation, over-exploitation, the random destruction of young fish due to unregulated fishing pressures and other factors. The findings from
(Siddiq et al., 2013; Galib et al., 2009 and
Chakraborty and Mirza, 2007), which found about the same causes for the loss in fish variety, support the conclusions from the present study.
