Study of fishing gear selectivity of Chanda beel, a floodplain in Bangladesh.
Floodplains, which are seasonal and may or may not have beels or low-lying depressed area carrying some perennial water, spread over almost all over the country. The floodplains are also used, as the seasonal abode, by a large number of fish, prawn, turtle, mussel and other aquatic animals. Of these, fish and prawn are the most important aquatic living resources essential for the people residing in an around floodplains (Alam et al., 1997). But in recent years the fish production of floodplains has decreased (DOF, 1995). Yadava and Sugunan (1992) stated that, the beel (floodplain) was subjected to indiscriminate fishing throughout the year. So regular stocking of Indian and exotic carps would necessitate a well planned fish capture schedule and deployment of optimum effort. This would also entail strict enforcement of mesh size, besides a calendar of fishing practices to be employed in different times of the year by the fishermen. In order to arrest the continuous decline in fish production in floodplains, government had undertaken a massive pilot stocking program with credit from the World Bank under Third Fisheries Project (TFP) which included Chanda beel (Figure 1) in Gopalgonj (DOF, 1990). Local and Chinese carp fingerlings were stocked in Chanda beel, in July 1992. Bangladesh Fisheries Research Institute (BFRI) had been associated with the TFP to support its research activities in the floodplains. Safeguarding the early growth stage of stocked fingerlings from exploitation is one of the key elements for the success of any stocking program. BFRI had, therefore, initiated gear selectivity study research in connection with the implementation of TFP project with the following objectives: 1) to describe types and characteristics of fishing gear used in the floodplains, 2) to determine their species and size (length) selectivity, and 3) to recommend fishing gear regulation, that protect the stocked fingerlings from exploitation. This gear selectivity study started in late June 1992. The results obtained during the monsoon season from June to October 1992 are summarized here.
No gear selectivity study on floodplains fishery has been under taken in Bangladesh before and published paper on this subject is also very scanty. However, many researchers have studied gear selectivity abroad. For example, Siddeek (1986) reported his mesh selectivity and biological impact studies on a new fish-cum-shrimp trawl in Palk Bay and El Musa (1982) published the mesh selectivity study in Kuwait. The "covered cod end method" has been described, among others, by Pope et al. (1975) and Jones (1976). According to Sparre and Venema (1992) most fishing gear, for example trawl gears, are selective for the larger sizes, while some gears (gill net) are selective for a certain length range only, thus excluding the capture of very small and very large fish. This property of fishing gear is called "gear selectivity".
[FIGURE 1 OMITTED]
Materials and Methods
For this study, a monthly data collection program was conducted at fish landing centers (para and bazar) and at fishing grounds. Fishermen who came to the centers with fishing gear were sampled for gear information and catch data collection. From cast net and push net, of which catches were rarely landed at the centers, the data were collected in the fishing grounds.
For each type of fishing, the gear characteristics (mesh size, length, width, structure etc.) were observed. The fishing practices (location and time of fishing, and fishing method) were observed in the field. The catches were sorted into species and total lengths of individual fish were measured in mm. For each type of gear, a number of collections (collection is the number of catches of a fishing unit with a type of gear) were made to obtain the desired size of sample population (the number of fish those have been measured), i.e. at least 250 fish for a dominant species in a given gear. But in certain cases, less then 250 fish were considered as dominant species due to their less availability.
For each type of gear, the species composition of the catches was studied to determine the species selectivity. To estimate size (length) selectivity of the species caught in gear, the [L.sub.50%] value and selection range ([L.sub.25%] - [L.sub.75%]) were calculated for each dominant species with the help of probit and linear regression. The [L.sub.50%] is the length at which 50% of the fish entering the gear are retained and 50% escape. It is also called "length at first capture". The selection range is the range of lengths between [L.sub.25%] (the length at which 25% of fish entering the gear are retained) and [L.sub.75%] (the length at which 75% of fish entering the gear are retained). The 50% retention length and the selection ranges (25% and 75%) were evaluated according to Pope et al. (1975).
The following procedures were followed to estimate [L.sub.50%] and selection range in each month
The range of lengths of the sampled population was divided in to about 9 to 13 length intervals, depending on the sample size. According to the intervals, the normal frequencies were established. The normal frequency were transformed to cumulative frequencies, and then to percentage (relative) cumulative frequencies. The percentage cumulative frequencies were then transformed to probits by using Table 1 Transformation of percentage to probit from the book of "Statistical Tables for Biological, Agricultural and Medical research" written by Professor R. A. Fisher and Dr. Yatos. A linear regression analysis was conducted between the length intervals (independent variable) and the probits (dependent variables). Using the length-probit regression equation, the lengths at probits of 4.32, 5.00 and 5.67 which correspond, respectively to 25%, 50% and 75% of the percentage cumulative frequencies were calculated as [L.sub.25%], [L.sub.50%] and [L.sub.75%].
Results and Discussion
During June to October, 1992 (monsoon season), a total of 125 collections (catches) were examined in Chanda beel. The fishermen use 17 types of fishing gear (Table 1 and Figure 2). The gears were classified into four groups; 1) fish net, 2) fish trap, 3) Hook and line and 4) Spear/ Harpoon.
According to Choudhury (1989), two categories of nets are mainly used for fishing in the beels I) Moving nets and ii) Stationary nets. The moving net was divided into three types: drag nets, dip nets, and cast nets. He also classified stationary nets into gill nets, hook and line, traps, katal fishing, bana fishing, and dewatering. A total of 40 species of fish were identified in the catches of different gears used by the fishermen in Chanda beel. The local name, common name, scientific name and family name of each species are shown in Table 2 and Figure 2.
Data of the above 17 types of gear were analyzed and the results described below:
Gill Net (Local name: Puti jal/ koi jal):
Material and structure
The gill net is made of monofilament nylon twine or double cotton twines, rectangular in shape, 45 -70 m long and 0.9 m wide. Usually floats are put on the upper edge of the net and weights on the lower edge. There are three mesh sizes; 2.54, 3.18 and 3.81 cm.
The net is usually set near surface water or mid water along the edge of aman paddy fields or of areas infested with water hyacinth or rooted vegetation. It is set in the evening and harvested in the morning or viseversa. The gill net is the primary fishing gear in Chanda beel during the monsoon season.
A total of 69 collections were examined. Table 3 shows the species and number in the catches of gill net. Twenty species of fish were found in the gill nets catches of the three mesh sizes. Almost all were the floodplain resident species, which begins breeding at the onset of inundation and grows during the monsoon flood season. Puti Puntius stigma, kholisha Colisa fasciata, shing Heteropneustes fossilis koi Anabas testudineus, tengra Mystus vittatus, taki Channa punctatus and baila Glossogobius giuris were dominant species while bheda Nandus nandus, baim, Mastacembelus armatus shoal Channa striata, magur Clarias batrachus, kakila, Xenentodon cancila were common. Pabda Ompok pabda, chanda Ambassis nama, tatkini/ raikhor Cirrhina reba, pholi Notopterus notopterus, gutum Lepidocepalus guntia, boal Wallago attu, boicha Colisa channa and darkina Esomus danricus were the minor species.
There was apparently a seasonal shift in the use of three different mesh sizes. The 2.54 cm mesh net was commonly used in June/ July (beginning of monsoon season), the 3.18 cm mesh from June to August and the 3.81 cm mesh net from August to September. The seasonal shift in mesh size from small to large from June to September corresponded to the growth of the target species. Also, there were more species caught by 2.54 cm and 3.18 cm mesh net in June/ July and August than in September, whereas the 3.81 cm mesh net caught more species in August and September than June/July.
[FIGURE 2 OMITTED]
Stocked carps were not found in the catches of gill nets. Fishermen also informed that gill nets (koi jal /puti jal) did not allow carp fingerlings to be caught. Apparently, the location and way of setting of net do not catch carp fingerlings, or the fish might be able to avoid the nets. According to Sparre and Venema (1992), gill net is "passive gears" i.e., the fish has to swim into the net to get caught. This implies that fish which moves fast, has a larger probability of encounter with the gear than slow moving fish. It is known that large fish move faster than small fish of the same species.
Table 4 shows the monthly [L.sub.50%] values and selectivity ranges ([L.sub.25%]- [L.sub.75%]) of dominant species. Puti Puntius stigma, kholisha Colisa fasciata, shing Heteropneustes fossilis, taki Channa punctatus, tengra Mystus vittatus, koi Anabas testudineus and baila Glossogobius giuris were caught by gill nets of three different mesh sizes from June to October. Puti Puntius stigma a small fish, the [L.sub.50%] values during the four month's period ranged between 7.66-7.92 cm for the 2.54 cm mesh net, between 7.10-8.06 cm for the 3.18 cm mesh and between 8.07- 9.61 cm for the 3.81 cm mesh net. The [L.sub.50%] values increased as mesh size increased, but only for August, September and October. There was no difference in the [L.sub.50%] values from June/ July to October for the 2.54 cm mesh net. This may suggest that puti Puntius stigma has a long spawning season to sustain continuous supply of recruits of same size ([L.sub.50%] from 7.66-7.92 cm) for 2.54 cm mesh net fishery during the monsoon season. No fish was caught by 3.81 cm mesh net in June/ July, indicating that mesh size was too large to catch this species in the early monsoon, when the fish was small. The selection of larger fish by larger mesh sizes were obvious in September and October and less so or absent in June/ July and August. The above differences in the size selection among the three meshes sizes and among months were for the change in the size composition of the fish population due to the continuous recruitment and growth of fish.
Kholisha Colisa fasciata is another small annual fish. The [L.sub.50%] values ranged between 6.44- 8.57 cm for the 2.54 cm mesh net, between 6.46-8.19 cm for the 3.18 cm mesh and 7.96- 8.57 cm for the 3.81 cm mesh net. The [L.sub.50%] increased as the mesh size increased in of August and September. It also increased from August to October for the 2.54 cm mesh net and from June/July to October for the 3.18 cm mesh and from August to September for the 3.81 cm mesh net. Very few fish were caught by 3.81 cm mesh net in June/July. There was a similar pattern in changes of [L.sub.50%] among the three mesh size nets and among the months for kholisha Colisa fasciata and puti. Puntius stigma These two small annual floodplain resident species perhaps with very similar life-cycle well corresponding to the hydrologic cycle. Similarly was observed in case of shing, Heteropneustes fossilis koi Anabas testudineus, taki, Channa punctatus and baila Glossogobius giuris.
Cast Net (Local name: Jhaki jal/ khepla jal):
Materials and structure
The cast net is circular net with a radius of about 3.7 m. It is usually made of cotton twines with weights around its edge. The center of the net has a rope of about 9.1 m. It has four different mesh size; 1.0, 1.5, 2.0 and 2.5 cm.
Fisherman ties the rope on one of his wrists and holds the net on his opposite shoulder and arm in a way that when the net is cast, it opens into a circular shape and falls on the water surface. Thereafter, the net reaches the bottom, and then fisherman pulls it up to shore to pick up the fish caught. Uually, the net is cast from river bank or fishing boat. It is commonly used in khal (canal), where water is clear of water hyacinth or submerged rooted vegetation. Because the fishing is more effective in shallow water, the cast net fishing are practiced more intensively in Chanda beel during the water ascending season (June/July) and receding season (October onwards).
Twenty five collections were examined in the fishing grounds. A total of 18 species of fin fish and prawns were found in the cast net catches of four different mesh sizes (Table 5). Of them, prawns were most dominant. The dominant fin fish species were variousmall species such as puti Puntius stigma, baila, Glossogobius giuris kholisha Colisa fasciata cancila a, chanda Ambassis nama and tengra Mystus vittatus. Minor species were taki Channa punctatus, baim Mastacembelus armatus, boal Wallago attu, mola Amblypharyngodon mola, gutum Lepidocepalus guntia, khorsola Rhinomugil corsula, kakila Xenentodon cancila, banshpata Danio devario, dhela Rohtee cotio, ghunia Labeo gonius, buguri, Mystus tengra cheng Channa gachua and gaura tengra Leiocassis rama. Major carps and common carps were not found in the catches. The fishing grounds of cast net in the Chanda beel were located primarily in big canal near inlets and outlets of the beel. It seems that it is not an effective gear for carps in Chanda beel.
Thirteen samples were used for estimating [L.sub.50%] and selective range for five dominant species chanda A.nama., baila G. giuris puti P. stigma, kholisha C. fasciata.and tengra M. vittatus. Their [L.sub.50%] values and selective ranges are shown in Table 6. The [L.sub.50%] value of chanda A. nama was 5.28 cm for the 1.0 cm mesh cast net, 5.99 cm for 1.5 cm mesh and 6.17 cm for 2.0 cm mesh net. The value increased as the mesh size increased which was seen for baila G. guris, kholisha C. fasciata , and puti P. stigma too. Also, as compared to the [L.sub.50%] obtained by the gill net, the values of baila G. giuris , puti P. stigma and kholisha C. fasciata caught by cast nets were much smaller than those caught by gill nets, due to the much smaller mesh sizes of cast nets (Tables 4 and 6).
Seine Net (Local Name: Ber jal):
Material and structure
Seine net is rectangular in shape, 61-91 m long and 1.5 m wide, made of cotton twines with floats on the upper edge and weights on the lower edge. Its mesh size varies from 0.5 to 2.54 cm.
The net is usually operated by a team of fishermen in shallow water area of beel proper where aquatic vegetation is scarce. The net surrounds the area and the vegetation inside is then cleared. Some water hyacinths are often kept on one side of the net as shelter for the fish. The fishermen pull the other side of net towards water hyacinth to reduce the surrounding area. When the area becomes small enough, water hyacinth is removed and lower edge of the net is pulled up to catch fish. The fishery is usually operated during the water ascending season and receding season, when the water level in the beel proper is low.
The seine net is more or less a species non-selective gear. The species and size composition in catches depends on fish species that are present while fishing, and thus they differ in location, time and season.
Only five collections were obtained in September and October. Puti Puntius stigma, chanda Ambassis nama, bheda Nandus nandus, banshpata Danio devario and kholisha C. fasciata and gutum Lepidocepalus guntia were the collections in October (Table 7). Rui Labeo rohita, catla Catla catla, and mrigal Cirrhina mrigala were present in the above months, and common carp was found in September and silver carp Hypophthalmichthys molitrix in October. The carps contributed 4.9% in September and 13.42% in October of the total number of fish in the catches. Due to drought, water quality deteriorated badly in the beel in these two months, particularly in the areas heavily infested by water hyacinths, rooted vegetation and aman paddy. In these areas dissolved oxygen (DO) contents at the depth of 1.5 m in the day time were often less than 2 ppm. Less than 1.0 ppm DO was recorded in heavily infested water hyacinth area (FRI, 1992). It is suspected that in the night, DO might drop down further to reach zero ppm in most part of the beel. Hence the carps in the beel gathered to open area (less vegetation) where DO was comparatively high, resulting in higher catches of carps in the seine fishery. Also, the mode of operation of this gear destroys the normal habitat of resident species possibly of stocked carp as well.
For the dominant small fish, the [L.sub.50%] value and selectivity range ([L.sub.25%] - [L.sub.75%]) were 5.0 cm (4.32 cm - 5.67 cm) for kholisha C. fasciata. in October, and 17.74 cm (12.29 cm - 23.17 cm) for kakila X. cancila , 6.31 cm (5.79 cm - 6.83 cm) for chanda A. nama. and 12.05 cm (10.78 cm -13.32 cm) for baim M. armatus in September (Table 7).
Because of few collections the sample sizes of carps in catches were insufficient to estimate [L.sub.50%] and selection range. The total length ranged between 16.0-29.0 cm for catla C. catla and 18.0-32.0 cm for silver carp H. molitrix in October.
Lift Net (Local name: Veshal jal/ khora jal):
Material and structure
Lift net is a type of fixed gear. It consists of two parts bamboo frame and net. The bamboo frame is triangular in shape. Its two arms are bamboo poles where the net is tighten. The frame is fixed on the bottom by several vertical bamboo poles. The net, made of cotton twines is also triangular in shape. It is about 9.0 m long on each side. Its mesh size usually differs in different parts of the net. It is 0.5- 1.0 cm in the central portion, 2.0- 2.5 cm near the two arms, and 1.0- 1.5 cm at the front side of the net.
Lift net is usually used in canal in an area that is free from water hyacinth. The front edge of net is faced against water flow. The net is lowered into water keeping on the bottom for a few minutes, and then pulled it up by the weight of fisherman who stands at the angle of the frame as a level. Then he picks up fish in the net by a dip net. The catchability of fish by the net depends on the movement of fish in water. It is operated mostly during the water ascending season and receding season when fish migrate in and out the beel.
The lift net is more or less non-selective gear, but it catches mostly those migratory species or highly mobile fish in the canal. A total of 27 species were identified in the 14 collections from June/ July to October (Table 6). The dominant species in the catches were small miscellaneous fish such as puti P.stigma, kakila X. cancila, kholisha C. fasciata chanda A. nama, baila G. guris and gutum L. guntia. The species, which are resident in the beel proper and less mobile such as koi A. testudineus, shing, H. fossilis taki C. punctatus, shol C. striata and magur C. batrachus, were rarely caught by the lift net.
Carps including catla C. catla, rui L. rohita, mrigal C. mrigala, silver carp H. molitrix common carp Cyprinus carpio var. Communis, mirror carp Cyprinus carpio var. specularis, grass carp Ctenopharyngodon idella and kalibaous Labeo calbasu were found in the catches in September and October, but not in June/ July. Except a few from natural sources, most of carps were from stocked fingerlings. Grass carps C. idella were from stocked fingerlings as a mix species. The carps in terms of number contributed 7.29% of the catches in September and 28.37% in October. Of them C. catla, rui L. rohita, mrigal C. mrigalal were dominant.
Due to limited number of collection, few species had enough samples for estimating [L.sub.50%] and selective range (Table 8). Puti P. stigma had the [L.sub.50%] value of 5.74 cm in June/ July, and increased to 7.52 cm in September and to 8.11 cm in October. The increments of the monthly [L.sub.50%] was faster for the lift net than that for the gill net (Tables 3 and 8), suggesting less size selectivity is lift net for this species. Chanda A. nama had the [L.sub.50%] of 5.58 cm in June/ July and 6.47 cm in September. For the remaining species, the [L.sub.50%] value was 5.95 cm for kholisha C. fasciata, 14.76 cm for kakila X. cancila, 25 cm for catla C. catla, 27.97 cm for rui L. rohita and 21.68 cm for mrigal C. mrigala.
Push Net (Local Name: Thela jal):
Material and structure
The push net is triangular in shape and consists of two parts, bamboo frame and net. The triangular frame is constructed with three pieces of bamboo poles. One of them is longer to use as a handle. The net which is conic shape is tied on the frame. The mesh size is 1.0 cm.
Push net is used by subsistent fishermen. One man can operate walking in shallow water and pushing the net along the shore, particularly in the area infested by water hyacinth or rooted vegetation.
Push net only catches small prawns and miscellaneous fish (Table 6). In this study only one collection was obtained in August. The catches were puti P. stigma (2 fish), kholisha C. fasciata (93) taki C. punctatus (3), baim M. armatus (1) and boicha C. channa (49).
Kholisha C. fasciata had sufficient sample size for the length selectivity analysis. It had the [L.sub.50%] value of 6.81 cm and selectivity range of 6.18 cm-7.24 cm (Table 8).
Tubular Trap (Local name: Dughair):
Materials and structure
Dughair is a tubular shaped bamboo trap. Its length is about 60 cm. The mouth is located at one end of the trap and has a diameter of 40.0 cm bearing a tongue, a small bamboo fence of about 20.0 cm long extending out from mouth. The tongue divides the mouth vertically into two equal size entrances. There are two uni-directive valves in the trap, one at the mouth and rest one in the middle portion to prevent the escape of fish and prawn. The tail of the trap is 53.0 cm high and has a small door to get the catch. The space between bamboo sticks (mesh) of the trap is about 0.8 cm.
The trap is usually set on the bottom of canal perpendicularly to the shore with its mouth facing towards canal and tail placing the shore line. A short bamboo fence (about 61.0- 91.0 cm long) is connected with tongue to increase the entrance of fish and prawn into the trap. There are about 20- 40 traps for each fishing unit. They are set in the evening and harvested in the morning or vise-versa.
Seventeen collections of Tubuler trap were obtained. They consisted of 12 species of fish and prawns (Table 6). Of them, prawns were the most dominant followed by baila G. guris. Prawn contributed 93.25% of the total catches in June/ July, and 46.42% in September. The catches of this species increased greatly from June to September. Prawns and baila occurred mainly in khals near the outlets of the beel, where the dughair fishery was intensive. The remaining species such as taki C. punctatus, shing H. fossilis, tengra M. vittatus, aire Mystus aor, koi, gaura, raikhor, kholisha, mola and boicha were minor species.
The [L.sub.50%] and selectivity range ([L.sub.25%] - [L.sub.75%]) of baila 18.20 cm and 14.86- 21.33 cm in August and 20.32 cm and 17.66- 22.94 cm in September (Table 7).
People use all possible types of fishing gear, ranging from bare hand to sophisticated seine and gill nets to catch fish and prawn from floodplains for decades. But they are not concerned about the productivity of this area. They fish indiscriminately which declines the fish production alarmingly. So, the guideline of using fishing gear is a crying need to pass legislation banning the use of harmful gear. This will help to grow of stocked carp and increase fish production through safe recruitment. Besides, extension program is necessary for the fishermen which will enhance the fish production. Seine and lift nets are identified as highly detrimental to the floodplain fish and hence those are to be restricted from June to October.
Alam, S.S., M.Y. Ali and C. Tsai, 1997. Open water fisheries of Bangladesh. In Bangladesh Centre for Advanced Studies, Eds., Tsai, C. and M. Y. Ali, Dhaka: Bangladesh Center for Advanced Studies and University Press Limited, pp: 137-152.
Choudhury, M., 1989. Resource Exploitation in Beels: Training in management of Beel (Ox-Bow Lake) Fisheries. Central Inland Capture Fisheries Research Institute, Barackpore, India. Associate Press Limited. DOF, 1995. Project Performa, Third Fisheries Project (Revised). Department of Fisheries, Government of the Peoples Republic of Bangladesh.
El Musa, M., 1982. Mesh Selectivity experiments in Kuwait. Report on the workshop on assessment of the shrimp stocks of the west coast of the Gulf between Iran and Arabian Peninsula, Kuwait, 17-22 October, 1981. FAO, Regional Fishery Survey and Development Project, Doha, Qatar. DP/RAB/0015.
FRI., 1992. Fish food study of the floodplains under the third fisheries project. Progress report, Fisheries Research Institute, Santahar, Bogra, Bangladdesh..
Jones, R., 1976. Mesh regulation in the demersal fisheries of the South China Sea area. Manila, South China Sea Fisheries Development and Coordinating programme. SCS/76/WP/34, pp: 75.
Pope, J., A. Margetts and J.M. Hamely, 1975. Manual of methods for fish stock assessment. Part 111. Selectivity of fishing gear. FAO Fisheries Tecnical Paper, 41( Rev. 1): 65.
Sparre, P. and S.C. Venema, 1992. Introduction to tropical fish stock assessment. Part 1. Manual. FAO Fisheries Technical Paper No. 306.1, Rev. 1. Rome, FAO, pp: 376.
Siddeek, M.S.M., 1986. Mesh selectivity and biological impact studies on a new fish-cum-shrimp trawl in Palk Bay, Srilanka. In The First Asian Fisheries Forum, Asian Fisheries Society, Manila, Philippines. Eds.,
Maclean, J.L., L.B. Dizon and L.V. Hosillos, Srilanka: Associate Press. pp: 417-420.
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(1) Shafiqur Rahman, (2) Abdur Razzaaque and (3) A.K.M. Saiful Islam
Bangladesh Fisheries Research Institute, Mymensingh-2201, Bangladesh.
Corresponding Author: Shafiqur Rahman, Bangladesh Fisheries Research Institute, Mymensingh-2201, Bangladesh. H/P: +8801730302661, email: email@example.com
Table 1: List of fishing gear found to use in Chanda beel during June/ July to October. Sl. Types of gear (Figure 2) No. 1 Fish Net i) Gill net (puti/ koi jal) ii) Cast net (jhaki jal) iii) Seine net (ber jal) iv) Lift net (veshal jal) v) Push net (thela jal) vi) Clap net (buri/ bhuti jal) 2 Fish Trap i) Tubular trap (ichar dughair) ii) Tubular trap (koi dughair) iii) Box trap (ghuni) 3 Hook and Line i) Regular long line (dhawn borshi) ii) Hook and line with water hyacinth as float (dhap/nol borshi) iii) Hook and line with bamboo stick (borshi) iv) Bamboo made hook (chasra) 4 Spear/ Harpoon i) Tuft of sharp-pointed steel wires (umbrella stick-rickshaw spoke) without barb (full-kuchi) ii) Tuft of rods with/without barb (jhupi) iii) Tuft of split-bamboo pieces with barbed iron point, which attached to the shaft by cords (jhuti) iv) Tuft of split-bamboo pieces, pointed end covered with iron cap (koach) Table 2: Species composition of catches of different mesh gill nets, Chanda beel, June/ July to September. Species 2.54 cm mesh 3.18 cm mesh Jun/Jul Aug Sep Jun/Jul Aug Sep Baila 38 14 7 258 57 117 Baim 10 1 3 46 97 35 Bheda -- 14 8 -- 68 72 Boal -- -- -- 10 2 -- Boicha -- 14 -- -- 22 -- Chanda 5 -- -- 10 -- 2 Darkina -- -- -- 3 -- -- Gutum -- -- -- 16 -- -- Kakila 8 1 - 7 6 41 Kholisha 348 88 191 422 286 242 Koi 238 8 -- 273 105 23 Magur -- -- -- 6 13 -- Pabda -- -- 2 -- 4 4 Pholi -- -- -- 8 3 -- Puti 275 251 308 389 284 435 Shol 13 -- -- 94 16 2 Shing 407 16 88 460 277 52 Taki 195 1 -- 380 66 18 Tatkini -- 1 -- -- -- -- Tengra 240 11 -- 268 108 34 Number Species 12 13 9 17 17 14 Fish 1777 420 607 2650 1414 1077 Collection 11 3 4 16 11 8 Species 3.81 cm mesh Jun/Jul Aug Sep Baila -- 68 62 Baim 3 2 5 Bheda -- 24 23 Boal -- 2 -- Boicha -- -- -- Chanda -- -- 1 Darkina -- -- -- Gutum -- 8 -- Kakila -- -- -- Kholisha 2 74 182 Koi 30 24 175 Magur -- 4 1 Pabda -- 1 8 Pholi -- -- -- Puti -- 87 287 Shol 2 1 18 Shing 65 72 114 Taki 33 23 -- Tatkini -- -- -- Tengra 14 19 29 Number Species 8 15 13 Fish 149 409 905 Collection 2 6 8 Table 3: Monthly [L.sub.50%] (cm) and selective range ([L.sub.25%] [L.sub.75%], cm) of different mesh gill nets for dominant species, Chanda Beel, June/July to September. Species Month 2.54 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Puti June/July 7.90 6.66 9.16 August 7.83 7.46 8.20 September 7.66 7.17 8.14 October 7.92 7.45 8.39 Kholisa June/July 6.56 5.62 6.86 August 6.44 6.02 6.86 September 7.06 6.63 7.49 October 8.57 8.00 9.13 Shing June/July 15.51 14.45 16.57 August -- -- -- October 17.89 15.30 20.49 Koi Jun/Jul 7.64 7.05 8.22 September -- -- -- Baila June/July -- -- -- September -- -- -- Taki June/July 12.34 11.13 13.55 Tengra June/July 12.77 10.62 14.90 Species Month 3.18 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Puti June/July 7.10 6.36 7.84 August 7.81 7.22 8.41 September 8.17 7.68 8.66 October 8.06 7.55 8.57 Kholisa June/July 6.46 5.87 6.97 August 6.88 6.33 7.43 September 7.45 6.99 7.93 October 8.19 7.72 8.65 Shing June/July 16.16 15.00 17.32 August 15.85 14.85 16.86 October -- -- Koi Jun/Jul 7.53 6.77 8.28 September Baila June/July 15.95 14.26 17.63 September 16.94 14.76 19.12 Taki June/July 13.40 12.66 14.17 Tengra June/July 11.45 10.49 12.40 Species Month 3.81 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Puti June/July August 8.07 7.45 8.69 September 8.22 7.65 8.80 October 9.61 9.01 10.29 Kholisa June/July -- -- -- August 7.96 7.42 8.51 September 8.57 8.10 9.02 October -- -- -- Shing June/July -- -- -- August 17.06 15.64 18.48 October 18.28 17.14 19.42 Koi Jun/Jul -- -- -- September 10.10 9.39 10.80 Baila June/July -- -- -- September -- -- -- Taki June/July -- -- -- Tengra June/July -- -- -- Table 4: Species composition of catches of different mesh cast net, Chanda Beel, June/ July to October. Species 1.0 cm mesh 1.5 cm mesh Jun/Jul Sep Jun/Jul Oct Baila 40 -- -- 2 Baim 11 -- -- -- Banshpata -- -- -- 5 Boal 3 -- -- -- Bugury -- -- -- -- Chanda 49 -- -- 11 Cheng 5 -- -- Dhela -- -- -- -- Gaura tengra -- 27 -- -- Ghunia -- -- -- 1 Gutum 7 -- -- -- Kakila - -- -- 1 Kholisha 34 - 127 -- Khorsola -- -- -- -- Mola -- Prawn (gura chingri) 261 -- -- -- Puti 34 -- -- 4 Taki 12 -- -- -- Tengra 14 -- 119 -- Number Species 11 1 2 6 Fish 470 27 246 24 Collection no. 3 1 1 2 Species 2.0 cm mesh Jun/Jul Aug Sep Baila -- -- 80 Baim -- -- -- Banshpata -- -- -- Boal -- -- -- Bugury -- -- -- Chanda 43 43 -- Cheng 1 1 -- Dhela -- -- -- Gaura tengra -- -- -- Ghunia -- -- -- Gutum -- -- -- Kakila -- -- -- Kholisha 91 -- -- Khorsola -- Mola -- -- 55 Prawn (gura chingri) 185 -- -- Puti 13 -- -- Taki 2 -- -- Tengra 14 14 -- Number Species 7 3 2 Fish 349 58 135 Collection no. 4 1 4 Species 2.5 cm mesh Jun/Jul Sep Oct Baila 22 44 21 Baim -- -- 3 Banshpata -- -- -- Boal -- -1 Bugury -- -- 8 Chanda 6 -- 24 Cheng -- -- -- Dhela -- -- 23 Gaura tengra -- -- 2 Ghunia -- -- 1 Gutum -- -- -- Kakila -- -- -- Kholisha 94 -- 2 Khorsola 1 -- -- Mola -- -- 2 Prawn (gura chingri) 69 -- -- Puti 1 31 14 Taki 1 -- -- Tengra 6 -- 11 Number Species 88 2 13 Fish 200 75 112 Collection no. 2 5 2 Table 5: Monthly [L.sub.50%] (cm) and selective range ([L.sub.25%]/[L.sub.75]%cm) of different mesh cast net for dominant species, Chanda beel, June/July to October. Species Month 1.0 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Chanda June/July 5.28 4.60-5.95 Baila June/July 10.91 9.62-12.2 September -- -- Puti June/July 5.08 4.46-5.7 September -- -- Kholisha June/July 4.80 4.24-5.38 Tengra June/July -- -- Species Month 1.5 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Chanda June/July 5.99 5.49-6.49 Baila June/July -- -- September -- -- Puti June/July -- -- September -- -- Kholisha June/July 5.48 4.96-6.0 Tengra June/July 13.8 8.98-18.6 Species Month 2.0 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Chanda June/July 6.17 5.72-6.62 Baila June/July -- -- September 12.84 5.73-19.19 Puti June/July -- -- September -- -- Kholisha June/July 6.16 5.68-6.63 Tengra June/July -- -- Species Month 2.5 cm mesh [L.sub.50%] [L.sub.25%]- [L.sub.75%] Chanda June/July -- Baila June/July 15.76 13.74-25.7 September 13.94 12.36-15.5 Puti June/July -- -- September 10.28 8.81-11.7 Kholisha June/July 6.79 5.60-7.98 Tengra June/July -- -- Table 6 Species composition of catches of seine net, lift net and tubular trap (ichar dughair), Chanda beel, June/July to October. Species Seine net Lift net Sep Oct Jun/Jul Sep Oct Aire -- -- -- -- -- Baila -- -- 18 13 2 Baim 91 -- 10 1 5 Banshpata 64 -- Bheda 78 -- -- -- 2 Boal -- -- -- -- 3 Boicha -- -- -- -- -- Catla 3 44 -- 20 79 Chanda 92 -- 30 198 2 Common carp 2 -- -- 1 10 Gaura -- -- -- -- 4 Grass carp -- -- -- -- 12 Gutum -- 147 102 -- -- Kakila 4 145 -- 250 352 Kaliboush -- -- -- -- 1 Kholisha 5 242 124 -- 152 Koi -- -- 1 -- -1 Magur -- -- -- -- 1 Mirror carp -- -- -- -- 5 Mrigal 2 5 -- 34 66 Mola -- -- 17 75 -- Pabda -- -- -- -- 15 Pholi -- -- 5 6 7 Galda chingri -- -- -- -- -- Puti 37 -- 369 253 216 Raikhor/tatkini -- -- -- 3 -- Rui 12 9 -- 7 72 Shol -- -- -- -- 1 Shing -- -- -- -- -- Silver carp -- 33 -- 1 18 Taki -- -- 10 -- 2 Tengra -- -- 6 1 -- Number Species 11 6 12 15 22 Fish 390 625 692 863 1027 Collection No. 2 3 2 3 9 Species Tubular trap (ichar dugair) Jun/Jul Aug Sep Aire -- 9 2 Baila 16 226 329 Baim -- -- -- Banshpata -- -- -- Bheda -- -- -- Boal -- -- -- Boicha 1 -- -- Catla -- -- -- Chanda -- -- -- Common carp 1 -- -- Gaura -- -- -- Grass carp -- -- -- Gutum -- -- -- Kakila -- -- -- Kaliboush -- -- -- Kholisha 1 -- -- Koi -- -- Magur -- -- -- Mirror carp -- -- -- Mrigal -- -- -- Mola 1 -- -- Pabda -- -- -- Pholi -- -- -- Galda chingri 594 260 -- Puti -- -- -- Raikhor/tatkini 1 -- -- Rui -- -- -- Shol -- -- -- Shing -- 17 -- Silver carp -- - -- Taki 17 15 -- Tengra -- 33 -- Number Species 9 6 2 Fish 637 560 331 Collection No. 4 4 4 Table 7: Monthly [L.sub.50%] (cm) and selective range ([L.sub.25%] and [L.sub.75%], cm) of push net, seine net, lift net and tubular trap (ichar dughair) for dominant species, Chanda beel, June/July to October. Species Month Push net [L.sub.50%] [L.sub.25%]- [L.sub.50%] Puti June/July September October Kholisha June/July August 6.18 6.18 October Chanda June/July September Kakila September Catla October Rui October Mrigal October Baila August September Baim September Species Month Seine net [L.sub.50%] [L.sub.25%]- [L.sub.50%] Puti June/July September October Kholisha June/July August 7.24 October 5.0 4.32-5.67 Chanda June/July September 6.31 5.79-6.83 Kakila September 17.74 12.29-23.17 Catla October Rui October Mrigal October Baila August September Baim September 12.05 10.78-13.32 Species Month Lift net [L.sub.50%] [L.sub.25%]- [L.sub.50%] Puti June/July 5.74 4.24-7.23 September 7.52 6.97-8.08 October 8.11 7.60-8.61 Kholisha June/July 5.95 5.45-6.45 August October Chanda June/July 5.58 5.03-6.12 September 6.47 5.77-7.07 Kakila September 14.76 11.73-17.78 Catla October 25.0 23.0-27.17 Rui October 27.97 24.37-31.55 Mrigal October 21.68 19.29-24.07 Baila August September Baim September Species Month Tubular trap (ichar dughair) [L.sub.50%] [L.sub.25%]- [L.sub.50%] Puti June/July September October Kholisha June/July August October Chanda June/July September Kakila September Catla October Rui October Mrigal October Baila August 18.20 14.86-21.33 September 20.32 17.66-22.94 Baim September Table 8: List of fish and prawn species caught by different gear, Chanda beel, June/ July to October. Sl. No. Local Name Common Name (Scientific Name, Family Name) 1 Aire Bagrid Cat fish (Mystus aor, Bagridae) 2 Baila Gobies (Glossogobius giuris, Gobidae) 3 Baim Mastacembelid eel (Mastacembelus armatus, Mastacembelidae) 4 Banshpata Minor carp (Danio devario, Cyprinidae) 5 Bheda Leaf fish (Nandus nandus, Nandidae) 6 Boal Eurasian catfish (Wallago attu, Siluridae) 7 Boicha/chuna Climbing perches (Colisa channa, Anabantidae) 8 Buzury Bagrid Catfish (Mystus tengra, Bagridae) 9 Chanda Snooks (Ambassis nama, Centropomidae) 10 Catla Indian major carp (Catla catla, Cyprinidae) 11 Cheng Snakehead (Channa gachua, Channidae) 12 Common carp Common carp (Cyprinus carpio var. Communis, Cyprinidae) 13 Darkina Minor carp (Esomus danricus, Cyprinidae) 14 Dhela Minor carp (Rohtee cotio, Cyprinidae) 15 Galda chingri Giant prawn (Macrobrachium rossenbergii, Palaemonidae) 16 Gaura tengra Bagrid Catfish (Leiocassis rama, Bagridae) 17 Gaura Schilbeid catfish (Clupisoma gaura, Schilbeidae) 18 Ghunia Carp (Labeo gonius, Cyprinidae) 19 Grass carp Chinese major Carp (Ctenopharyngodon idella, Cyprinidae) 20 Gutum Loaches (Lepidocepalus guntia, Cobitidae) 21 Kakila Needle fish (Xenentodon cancila, Belonidae) 22 Kaliboush Indian major carp (Labeo calbasu, Cyprinidae) 23 Kholisha Climbing perches (Colisa fasciata, Anabantidae) 24 Khorsola Mullet (Rhinomugil corsula, Muglidae) 25 Koi Climbing perches(Anabas testudineus, Anabantidae) 26 Magur Air breathing catfish (Clarias batrachus, Claridae) 27 Mirror carp Common carp (Cyprinus carpio var. specularis, Cyprinidae) 28 Mrigal Indian major carp (Cirrhina mrigala, Cyprinidae) 29 Mola Minor carp (Amblypharyngodon mola, Cyprinidae) 30 Pabda Eurasian catfish (Ompok pabda,Siluridae) 31 Pholi Featherback (Notopterus notopterus, Notopteridae) 32 Prawn (gura Freshwater small shrimp (Macrobrachium chingri) lomarrei, M. Dayanus, M. Dolichodactylus etc. & Leander styliferus, Palaemonidae) 33 Puti Minor carp (Puntius stigma, Cyprinidae) 34 Rui Indian major carp (Labeo rohita, Cyprinidae) 35 Shol Snakehead (Channa striata, Channidae) 36 Shing Stinging catfish (Heteropneustes fossilis, Heteropneustidae) 37 Silver carp Chinese major carp (Hypophthalmichthys molitrix, Cyprinidae) 38 Taki Snakehead (Channa punctatus, Channidae) 39 Tatkini/Rikhor Carp (Cirrhina reba, Cyprinidae) 40 Tengra Bagrid cat fish (Mystus vittatus, Bagridae)
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|Title Annotation:||Original Articles|
|Author:||Rahman, Shafiqur; Razzaaque, Abdur; Islam, A.K.M. Saiful|
|Publication:||American-Eurasian Journal of Sustainable Agriculture|
|Date:||Dec 1, 2009|
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