International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

Productivity of Bubu As Eel Trap Installed In Swamp Water Around University Of Bengkulu Dede Hartono, Eko Nofridiansyah, Randi Anoma Putra University of Bengkulu, Indonesia Jln. WR Supratman, Bengkulu 38371 Phone: (0736) 21170-Fax: 22105; email: [email protected]

ABSTRACT

Eel (Anguilla spp) is economically and valuable fish. This fish is important not only in national but also in international market. Eels are catadromous fish that grow in freshwater, such rivers and lakes. ells will migrate to the deep sea for spawn. Eel classified into predatory fish, its main food is fish. In Bengkulu province, eel usually caughted by fishermen that divided into two size classes which are fingerling and Yellow eel (adult eel). Fishermen catches eels using “bubu” traps. Bubu is a gear that has cage shaped, fish can enter easily, but fish will be blocked to go out. Bubu is a passive trap, can be made from bamboo, rattan, or wire. catch area of Eel in Bengkulu located at DAS Air Hitam around the University of Bengkulu. The results of this study are expected to provided additional insight and information on fishing eel in nature and can be a reference for further research. Primary data in this study were the number and weight of fish catches eel. Productivity of fishing gear are caught with a weight per unit effort of his arrest, where efforts to arrest here can be a form of fishing gear or trip. The use of fishing gear traps do as much as twenty-trip, with a productivity level of 468.64 grams / trip. Keywords : eel, bubu trap, productifity, swamp

INTRODUCTION Eels (Anguilla spp) are economically and valuable fish. This fish is important not only in national but also in international market, both in size elver, fingerling and adult size. Eels are catadromous fish that grow in freshwater, such rivers and lakes. ells will migrate to the deep sea for spawn (Kottelat et al., 1993). . Eel classified into predatory fish, its main food is fish (Samuel et al., 1998). Eels distributed in several regions in Indonesia, also at Bengkulu province. Bengkulu province is located at 20 16’ LU, 30 31’LS and 1010 01-03 41’ BT, Bengkulu province also located infront of Indian Ocean. Bengkulu has the potential of marine fisheries resources, including eels fisheries (Sugeha and suharti, 2008). Eels fishing areas in Bengkulu province spreaded in several swamps, rivers, and estuaries. Catch area of Eel in Bengkulu located at DAS Air Hitam around the University of Bengkulu. Fishing gear that used to collect finggerling eels made from bamboo or rattan. Eel that catched in Bengkulu province classified into two sizes. Fingerling eels has size smaller than 30 cm, and yellow eels has size more than 30 cm (Putra, 2016). Bubu can be operated to cathce eel during a years, with various productivity every each day. Productivity of bubu influenced by several factors such as location, traps position, feeds and weather conditions. Productivity of fishing gear is an important

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International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

indicator that can be used as a yardstick to determine the variability of production and abundance of fish (Mc Cluskey and Lewison 2008). However, the information about how much productivity of bubu very limited. Therefore it is necessary to research on productivity of bubu, especially that operated at Air Hitam River around the campus of the University of Bengkulu. The aim of this study was to determined the productivity of bubu that operated at Air Hitam River around the campus of the University of Bengkulu. The results of this study are expected useful for sustainable of the uses of eels.

MATERIALS AND METHOD This research was conducted in marsh around the campus of the University of Bengkulu, included Air Hitam River Watershed of Bengkulu city. Data is collected on October 2015 until April 2016. This research used experimental fishing metod by 20 of bubu. Bubu traps are setted in multiple locations with water depths ranging from 0.5 to 1.0 meter, and the distance between the traps was 3 meters. Bubu traps laid by the position of the mouth facing towards the flow of water and may be fed in the form of snails (keong emas). Bubu traps installed in the late afternoon and lifted to harves in the next morning. Productivity of bubu was calculated using the formula from Sparre and Venema (1999): Productivity =

Total catches Total Effort (trip or Unit of traps)

RESULTS AND DISCUSSION Location Of The Research Location of this study is Air Hitam River watershed, around campus The University of Bengkulu. This location has characteristics such plants that can be live in swamp (ferns and shrubs). In addition, there are animals swamp such as fish, lizards, leeches, birds and eels. Conditions of the study area can be seen in the picture below.

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International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

Figure 1. Condition of reasearch location at Air Hitam River watershed, around campus The University of Bengkulu

The the Air Hitam River Watershed has slow flow of water, and muddy substrate. It is impacted on hight brightness of water. This is the goog condition for eels habitat. The result of measured water quality presented in Table 1. Tabel 1.

Water quality of location

No

Parameters

DAS Air Hitam Dry Seasson Rain Seasson 28.7 27.2 8.3 6.5

1. 2.

Temperature (0C) pH

3.

Brightness (%)

100

100

4.

Salinity (0/00)

3.4

1.7

5.

Disolved Oxygen

6.3

7.2

6.

Curent Flow

<10

<10

7.

Depth (cm)

50 – 80

70 – 90

8.

Substrate

Muddy

Muddy

Source: Primary Data, 2016 Water quality parameters was measuremented during rain sesson and dry sesson.

It can be figured the water quality condition of location during a years

accurately. Tabel 1 figured the condition of the water quality when rain and dry sessons. Furthermore, the range of water quality parameter was accordance for eels. According to Samsundari dan Wirawan, (2013) eels can be live on e clear water quality conditions with optimum temperature 29 ° C, pH 7-8, and the dissolved oxygen at least 5 mg/L.

Description of Bubu Traps Silindries bubu traps were used in this study and made from bamboo. The traps have gab arranged 0.5-1.0 cm, and two injab in inside. Injab has a function as door where fish can enter easily but they can not get away (Subani and Barus, 1989). The front side of bubu has a diameter 20 cm, while the behind side has diameter 30 cm. Total length of bubu was 75 cm. The shape and size of bubu traps based on targeted catches and location.

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International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

Figure 2.

Bubu traps for cathed ells

Bubu traps that used to catched eel fishing have several advantages, which are easily to made and cheap, simply to operated, high durability, and could catch ells in living conditions. Operation Method Operating of bubu basically same with the other traps.

Bubu traps laid in stagnant

waters, the bubu’s mouth should be faced toward river flow. The snails (keong mas) were used as bait to incrase cathces. Snails has a function as a stimulus for eel into the trap. Bubu trap setted in the afternoon, then soaked for one night. After one night, bubu has harvested in the tomorrow morning (Setiyanto at all.,

2003).

Cathes Result Bubu trap catched several species including eels, snackhead fish, betok, and belut from 20 trips. The catches were grouped into two categories e.g eels and non eels (snackhead fish, betok, and belut). Totally, there was 26.780 grams of catches during this research, which is 9.373 grams of eel (35%) and 17 407 grams of non eel (65%). Total catches of eels were 229 individual, and 9.373 grams. All catches off ells were fingerling size (31-53 gr/ individual), and has average of weight 41 gr/individual (Figure 3).

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International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

Figure 3. Fingerling ells that cathed from location of research The total catches of eels has variation amount and weight every each trips.

Data total

amount and weight of eels that catched every trip are presented in Table 2. Table 2. Data total amount and weight of eels that catched every each trip No trip 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

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Tanggal

18/10/2015 19/10/2015 26/10/2015 07/11/2015 08/11/2015 10/11/2015 13/11/2015 14/11/2015 25/11/2015 04/12/2015 13/12/2015 22/12/2015 24/12/2015 25/12/2015 03/02/2016 08/02/2016 11/02/2016 09/03/2016 18/03/2016 19/03/2016 Jumlah

Jumlah Hasil Tangkapan Sidat Ekor Gram 7 234 10 450 7 235 8 317 7 273 5 165 14 628 13 493 17 626 14 640 11 588 15 638 8 317 10 316 13 502 16 790 11 427 9 280 18 812 16 646 229 9377 Sumber: Data Penelitian, 2016

International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

Catches Productivity Catches productivity is ability of fishing gear to catches the fish. Productivity is calculated by divide total amount of catch with total trips or fishing gears that used (Sparre and Venema, 1999). In this research, productivity was calculated using 20 unit traps. Data productivity of eel that catched from 20 unit traps per trip are presented in figure 3. 45 40

Catch (gr/unit)

35

31.3 32

31.4

30 25

31.9 29.4

10

Rainy

25.1

24.65

22.5

32.3 9

21.35

20 15

40.6

39.5

15.85 13.65 11.7 11.75

15.85

15.8

13

14

Sunny

8.25

5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Number of Effort

Figure 3. Catches Productivity of bubu traps to catched ells every each trips The average of productivity was 23.4 g/unit trap, while the highest productivity was at 19th trip (40.6 g/unit) and the lowest was at 6th trip (8.25 g/unit).

The average of

productivity was compared with average of total catches of fingerlings eels (41 g/ individual), so 11 individuals of eels was catched by 22 bubu traps every each trips. In other words every two bubu traped one eel. The productivity of bubu that operated in the swamps around campus of the Bengkulu University was low.

Catches productivity

are influenced by several factors such as biological, technical and interactions between bubu and ells (Kenchington, 1996). Biological factors can be impacted on the value of catches productivity by stock of ells in the cathed area. If the fish stock is hight, the catches productivity value also high, and vice versa. Operation of bubu during this research used 20 trip, that have resulted 23.4 gr/unit trap of productivity value. This value was categorized into low. It might be suspected that stocks of eels in fishing location was low. It is normally, because every

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International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

each level trophik that created the community and ecosystem either more or less (Nybakken, 1982; Bakun, 1996). Therefore, to increase the catches productivity of eels need explored new eel fishing area, which has higher eels stocks. Design, construction, materials, and the selectivity of bubu were categorized

into

technical factors. Both technical and biology factors can be impacted on the value of catches productivity. If technical capabilities was good, than biological factor also would be good, and productivity will be increased (Hilborn, 1985). Catches data showed that most of the catch from non eel (65%). It is indicated that technical ability of bubu to catched eel was low, especially on technical efficiency and selectivity of bubu. There were several factors to increase the productivity of bubu, which are : 1. Minimize the injab to blocked other fish such as betok and snakehead fish; 2. Changed the feed that favored by eels; 3. Introduction the new fishing gear of eel that more effective and selective to catched eels fingerling. Interactions between bubu and eels stock is last factor that improve the productivity of bubu. If the interaction between bubu and eels stock is hight, than opportunity to get a high productivity will be increased. The meaning of interaction between bubu and ells is the abilities of ells to find the location that instaled the bubu traps. The best location to instaled the bubu were close from ells nest, ells migration track, and fiding ground of ells. those factores will be increased value of interaction. In this study, cathces area were swamp areas that have a lot of bushes that bordered between one location to another. At this location, the interactions between bubu and eel influenced by water volume. High water volume will be connected the locations that had been isolated to another location, it have been impacted on the abilities of eels to find bubu traps. This condition can be seen on Figure 3, Rain will incrase the water volume, than the productivity of ells also will be increased. Vice versa, when the water volume was small (no rain) will be declined the productivity. It means that effective time to cathed eels using bubu in the swamp area around campus the University of Bengkulu was on rain season or when the water volume increase.

CONGCLUSION Productivity of bubu as eel traps that operated at Swamp Water Around University Of Bengkulu were relatively low. Biological factors, technical factors and interactions 206

International Seminar sustainable utilization of coastal resources in tropical zone, 19-20 October,2016, Bengkulu, Indonesia

factors betwen bubu traps and eels are several factors that impacted on catch productivity

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