STATUS OF THREATEN FISH SPECIES IN NARSUNDA RIVER

To identify the threatened fish species and focus on fish biodiversity conservation in the Narsunda River Kishoreganj Sadar, Kishoreganj district, the present study was conducted for a time period of 6 months (April-November, 2012). A total of 23 threatened fish species were identified in the river among them, 9 vulnerable, 11 endangered and 3 critically endangered species as well as 8 exotic fish species were also found in the River. The fishing gears used by the fishermen in Narsunda River includes 4 types of nets, 3 types of traps, 3 hooks and lines and 2 types of wounding gears whereas major fishing craft and gears were mainly wooden boat and seine net (locally called ‘ber jal’) respectively. Due to environmental degradation and manmade causes the biodiversity of this river decreasing day by day and it could be minimized by proper management and conservation techniques.Res. Agric., Livest. Fish.5(2): 259-268, August 2018


INTRODUCTION
The fish and fisheries sector play a very important role in national economy of Bangladesh.The principal sources of fish are inland fisheries and artisanal marine fisheries.Once these species were available in our water bodies but now the availability of the species declining day by day rapidly due to ecological degradation, indiscriminate fishing, use of pesticides, destruction of habitat, obstruction of breeding migration, use of restricted fishing gear and fishing pressure.Organochlorine pesticides are highly toxic to fish and other aquatic organisms.In sub-lethal doses, organochlorine pesticides affect the reproductive physiology of the fish (Mazid, 2002).Recent estimates suggest that worldwide 20% of all freshwater species are extinct, endangered or vulnerable (Moyle and leidy, 1999).Presently fish and fisheries sector contribute 58% of total protein intake, 4.43% to GDP, 22.21% to agricultural production and 2.73% to foreign export earning of the nation (DoF, 2012).Fisheries sector supplement not only the food and nutrition sector but also the job sector.IUCN Red List (2003) revealed 54 threatened species of fishes in Bangladesh, some of them are: Grey feather back (Notopterus notopterus), Freshwater eel (Anguilla bengalensis), Snakeheads (Channa marulius, C. barcaand C. orientalis), Darkina (Rasbora rasbora), Bhagna (Labeo boga), Olive barb (Puntius sarana), Mahashol (Tor tor), Baghair (Bagarius bagarius), Bacha (Eutropichthys vacha), Tara baim (Macrognathus aculeatus), Neptani (Ctenopis noblis), Napitkoi (Badis badis) and Bhanganbata (Labeo bata).No such endangered or threatened list of marine fish is not available in Bangladesh (Ahmed, 1995).

MATERIALS AND METHODS
Data and sample collection were carried out mainly in fishing spots, fish markets and landing centers in and around Narsunda River in Kishoreganj District.Ten study spots were selected under 6 villages in 5 Union in Kishoreganj District.This study was conducted for six months; from April to November, 2012.Frequent field visits (twice a month) were made during this time to collect necessary information.For questionnaire interviews, simple random sampling method was followed for 3 fishermen, 2 aratdars and 2 retailers in each study site per survey.

Collection of fish sample
To record the fish diversity of Narsunda River, fish species samples were collected and taking necessary information.The fish specimen samples were collected with the help of fishermen from fishing spot and from retailers of fish markets and landing centers.For this purpose, periodic visits were made in different spots of the study area.

Data collection
Data on overall availability of fishes from Narsunda River were collected according to questionnaire survey, field visit and fish market survey, fish 'arat' and fishing spots survey and from fishermen adjacent to river.Entries for different types of data were done using MS excel spreadsheet for the computational and statistical analyses of data.

RESULTS
As Narsunda River is one of the important and long river in the northern part of Bangladesh it serve as a nursery, breeding and feeding grounds of many of the threatened fish species.Waters are available for about 5-7 month (April-November) in this river and fishermen harvest fish mainly during April to November and January to February.A total of 23 threatened fish species under 7 orders were recorded during the investigation period.Out of 23 threatened fish species (Figure 1) 9 species belonged to orders Cypriniformes followed by Siluriformes (4), Perciformes (4), Channiformes (1), Mastacembeliformes (2), Osteoglossiformes (2) and Synbranchiformes (1).

Name of groups
Figure 1.Threatened fish species under different orders identified from Narsunda River.

Scientific name Local name
Critically endangered

Berilius bendelisis
JoiaTirulr/Tila  All of these fishes are cultured in ponds around the study area.

DISCUSSION
Among 23 threatened fish species found Narsunda River, there were 9 vulnerable, 11 endangered and 3 critically endangered species out of 54 threatened fish species of fresh and brackish-waters of Bangladesh (IUCN Bangladesh, 2003).In our study period, we have found a total of 8 exotic fish species in Narsunda River.The fish species were particularly available during high rainy season when the river was flooded.During our study we have recognized different types of fishing gears and methods used in Narsunda River to collect fish.A total of 5 types of nets (Jhaki jal, Dharma jal, Thela jal, Current jal, Berjal), 3 types of traps (Daudi, Charo, Hogra), 3 types of hooks and lines (Borshi, Nolborshi, Boalaborshi), 2 types of wounding gears (Koach, Achra) and 2 types of other fishing methods and different types of boats were recorded in Narsunda River.

CONCLUSION
It is concluded that the study was conducted to determine the threatened fish diversity from Narsunda river in Kishoreganj Sadar Upazilla under Kishoreganj district for a period of six months from April to November, 2012.The objectives of this study were set to observe the threatened fish diversity and status of fish in Narsunda River.Regarding the status of availability of endangered fish species in this study areas, 7 species were available, 4 rarely available and 17 not available (out of 28 reported by IUCN Bangladesh).Fishermen were found to be fishing during April to November and January to February.They used mainly traditional boat some fisherman may also use engine boat for fishing as fishing craft.During the study period it was also found that the fish biodiversity of Narsunda River is declining at an alarming rate.So, it is necessary to improve the habitat by following the national policy planning authorities should recognize the necessity for conservation of biodiversity, and ensure multi-sectoral coordination for it, Government agencies involved in biodiversity conservation should be strengthened, and new agencies should be created wherever necessary, Agencies for the survey of fauna and microorganism.

Figure 2 .
Figure 2. Availability of threatened species of Narsunda River

Figure 3 .
Figure 3. Availability of vulnerable fish species of Narsunda River

Figure 4 .
Figure 4. Availability of endangered fish species of Narsunda River

Figure 5 .
Figure 5. Threatened fish not available from Narsunda River

Table 1 .
List of threatened (critically endangered, endangered and vulnerable) fish species available from Narsunda river

Table 2 .
List of threatened fish species not available from Narsunda River

Table 3 .
Exotic fish species available from Narsunda River Ahmed et al. (2004)1).(2009)reported114fish species under 29 families from Chalan beel.Kostori et al. (2011)Found 82 SIS fish belonging to 10 orders, 22 families and 46 genera were recorded.The order Cypriniformes (42.68%) was the most dominant order comprising 35 species.The most dominant family of the order Cypiniformes was Cyprinidae (77.14%) comprising 27 species, which is similar to the present study.Ahmed et al. (2004)recorded a total of 52 fish species in Shakla beel (Brahmanbaria) of Bangladesh.