1.       Introduction

Catfish is one type of freshwater fish consumption that has important economic value and much in demand by local and international community. The potential of catfish exports to the European market is increasing with the issuance of policies to limit the hunting of cod. Instead, the European community began to turn to white catfish and had a texture similar to cod. Currently 80% market share of catfish in the world and 25% market share of catfish in the European market is dominated by Vietnamese patin [1].

 According to Gustiano et al. (2003) [2], in the world there are 25 species of catfish and 14 species of which are found in Indonesia. One of the most widely known catfish species and dominates domestic catfish products is Siamese catfish (Pangasianodon hypophthalmus). Siam catfish can grow rapidly in the community because it has many advantages, including easy cultivation process, fast growth, relatively more resistant to disease and environmental stress. However, according to the Directorate General of Aquaculture Fishery (2005) [3], the lack of Siamese catfish is a character of yellowish meat that is less attractive to consumers from developed countries who prefer white fish meat. Indonesia also has several types of white fleshy catfish, one of which is jelly catfish (Pangasius djambal). Jambal catfish are found in the Kahayan river of Palangkaraya, Kapuas Sanggau, Barito Muara Tewe, Batang Hari Jambi, Musi Palembang and Indragiri Rengat (Pouyaud, et al., 1998) [4]. According to Gustiano et al. (2003) [2], jambal catfish has white meat character and is a potential species to be developed as one of the mainstay commodity of aquacultureGermination has an important role in the development of catfish jambal, because the availability of seeds continuously in sufficient quantities is one of the key factors in the continuation of the catfish jambal cultivation activities. Although it has been released since 2000 based on the Decree of the Minister of Agriculture No. 265/Kpts/IK.240/5/2000, the development of cat fish cat fish in the community is still very limited. This is due to the lack of information about technical cultivation of catfish jambal, especially aspects of biology such as growth and survival. Bachiel & Le Cren in Nurlaela et al. (2010) [5], said that one of the most influential aspects in the success of fish farming is the density of stocking of fish that is kept. Hepher & Pruginin (1981) [6], adding that increased density will be followed by a decrease in growth rate and at certain density levels growth will stop. However, the obstacles that still occur in the community is the absence of information about the optimum density level for the maintenance activities of larvae/catfish cat fish jambal. Therefore, a study was conducted to investigate the effect of solid stocking on growth performance and survival rate of larvae of jet fish.

 2.       Materials and Methods

This research was conducted at Testing Laboratory of Patin Hatchery of Fish Breeding Research Institute (BPPI), Sukamandi in February - March 2016. The study was conducted using Completely Randomized Design with three density treatments, ie 30, 60 and 90 head/liter, each repeated as many three times. The tested fish were larvae of artificial spawning result of selected catfish jambal with total length 0,50 cm and average weight equal to 0.0005 gram. The test fish are maintained using a 60 x 30 x 40 cm3 aquarium with 25-liter water maintenance volume equipped with aeration installation. The study was conducted for 28 days of maintenance.

The larval catfish larvae begin to feed 36 hours after hatching, because during that time the larvae still have egg yolks that stick to the body and are absorbed for food. Feeding of naupli Artemia sp. Given for 5 days until maintenance day 7. Nauplii Artemia sp. Given every 2 hours on the first day of feeding and every 3 hours on the second day until the fifth day of feeding. Then continued with natural feeding using a silk worm smoothed to day 12, with feeding frequency every 3 hours. After the larvae were 14 days old, pellet meal was given in the form of powder with 38-40% protein content, with feeding frequency every 4 hours.

The parameters observed included daily growth rate, daily weight growth, specific weight growth rate and seed survival rate. Water quality parameters such as dissolved oxygen, temperature, pH, and turbidity were observed every 10 days using the Water Quality Checker (WQC) tool, while the nitrite and total ammonia parameters were observed by titrimetry in the laboratory. To know the growth of the daily length is calculated based on the formula [7]:

                                                                                                                       PLH=  (Lt-Lo)/t

Where: PBH= Daily weight gain (grams / day)

Wt= The average weight of seed end (gram)

Wo= The mean initial weight of larvae (grams)

T = Maintenance time

The growth of daily weight is calculated based on the formula [7]:

                                                                                                                          PBH=  (Wt-Wo)/t

Where: PBH= Daily weight gain (grams / day)

Wt= The average weight of seed end (gram)

Wo= The mean initial weight of larvae (grams)

T = Maintenance time

Specific seed growth rates of test fish were calculated using the formula [8]:

                                                                                                                        SGR=√(t&Wt/Wo)- 1 x 100%

                     Where: SGR= Specific Growth Rate (%)

T = Maintenance time (day)

Wt = The final weight of the seed (gram)

Wo= The initial weight of seed stocking (gram)

Seed test seeds were calculated using the formula [7]:

                                                                                                                          SR=  Nt/No  x 100%

Where: SR= Sintasan (%)

Nt= Number of seed harvest (tail)

No= The initial number of seed stock (tail)

Data of weight growth, standard length, total length and seed survival were analyzed using variance analysis. To know the more specific difference between the treatments, the smallest difference was done using the SPSS 19 program.

 3.       Results and Discussion

 The results of observation on jetal catfish seeds that were kept with different density showed the final weight, daily weight gain and specific growth rate significantly different between treatments (P <0.05). The result of the research shows that the higher the stocking density the slower the growth of weight will decrease. The best growth profile was demonstrated by treatment of 30 head / L with daily growth rate of 0.0416±0.0033g/day and a specific growth rate of 31.58±0.36%. The lowest growth rate was demonstrated by the treatment of 90 heads/L with a daily growth rate of 0.0261±0.0049g/day and a specific growth rate of 29.36 ± 0.91%, whereas the treatment of 60 heads/L indicated a non- Was significantly different from the treatment of 30 tail / L and 90 head / L (Table 1).

Description: The value followed by different superscript letters in the same column shows a significantly different value (p <0.05).

 The observation of jambal catfish seeds which were kept with different density of stock showed the total final length and the daily length increase which was significantly different between treatments (P <0.05). In line with the rate of growth of weight, the results of a solid study of the distribution of jawal catfish seeds showed that the higher the density of the spreading the longer the growth rate will be slowed down. The highest daily growth rate was shown by the treatment of 30 tail / L of 0.16±0.01 cm / day, followed by the treatment of 60 heads / L giving no significant difference with the treatment of 90 heads / L of 0.14±0.01 and 0.13±0.01 cm / day (Table 2). Rochdianto in Nurlaela et al. (2010) [5], explains that fish will experience a decrease in growth rate not even grow as a result of space competition. Kadarini et al. (2010) [9] adds that the density of the spreading at some point can lead to competition of space and the seizure of oxygen dissolved in fish, can also cause fish to experience stress, thus inhibiting metabolism and decreasing fish appetite.

 The survival rate of jambal catfish seeds on maintenance with a density of stocking of 30, 60 and 90 heads/L gave no significant difference (P> 0.05). Nevertheless, the highest survival rate was achieved by treatment with highest density of 39.96%, followed by treatment of 30 tail/L and 60 tail/L of 35.33% and 33.33%. According to Budiardi et al. (2007) [10], fish that are kept with too low density tend to be less aggressive in the absence of competition in obtaining space and search for feed.

Description: The value followed by different superscript letters in the same column shows a significantly different value (p <0.05).

 The results of observation of water quality parameters during the study showed that the values ​​of temperature range, dissolved oxygen, pH, turbidity, ammonia and nitrite among treatments showed no significant difference. At the parameters of temperature, pH, dissolved oxygen and turbidity are within the optimum range and are still within the tolerant tolerance limits for survival and optimum growth, but on the parameters of ammonia and nitrite have exceeded the optimum limits for growth and survival of jetal catfish seed (Table 3)

4.       Conclusion

 Different density had a significant effect on larvae growth of jetal catfish (p<0.05) but did not have a significant effect on larval larvae (p>0,05). The optimal distribution density for indoor catfish jambal induction by 30 tail/L, but still can be maximized up to 90 head/L with relatively slower growth consequences.

Table 1: The performance of jawal catfish seed weight growth on different dispersing density.

Table 2: Horizontal growth and survival rate of jugal catfish seeds at different dispersing densities.

Temperature

Table 3: Water quality of Patine jambal seed maintenance at different dispersing densities.

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