MASS REARING OF GOLDFISH LARVAE AND JUVENILES UNDER CONTROLLED CONDITIONS

Sławomir Krejszeff¹, Paweł Stępniak², Dariusz Kucharczyk¹, Andrzej Mamcarz¹, Roman Kujawa¹, Katarzyna Targońska^1
1 Department of Lake and River Fisheries, University of Warmia and Mazury in Olsztyn, Poland
² Gosławice Fish Farm, Poland

ABSTRACT

The mass rearing of goldfish larvae and juveniles was carried out under controlled conditions. Two of main aquacultural factors: food regime and stocking densities were studied. During rearing larvae and juvenile goldfish in captivity, dry food can not be used as only one kind of offered food. Initially, fish fed only with this food grew slower and during rearing the mortality significantly increased. After few weeks of rearing, all fish from these groups were died. It was in contrast with fish survival in groups fed with mixed food. As an optimal stocking density from tested in this work, the 1700 specimen per m³ was chosen, with fish survival over 85%. After six weeks of main rearing, the goldfish were in market size.

Key words: goldfish, juvenile, larvae, mass rearing.

INTRODUCTION

Goldfish (Carassius auratus auratus L.) is one the most popular and economically important of non-consumed fish in the world [5,3,4]. Also in Poland, the economical changes and western-Europe life style developed a new need – building beautiful water gardens with colourful fishes. Koi carp is appropriate for bigger ponds, whereas goldfish can live in smaller ones, and domestic aquariums. A lot of beautiful specimens of goldfish are imported to Poland from China, Thailand and other countries. However, a lot of them are not accustomed to Polish climate conditions. It causes a high mortality of these fishes, especially during winter [9]. On the other hand it opens a way for the next transports or production goldfish in Poland.

In many countries there are developed farm, in which only goldfishes are reared. Global production of these fishes is very high. Annual production is being estimated as over 22 millions commercially size specimens only in Italy [2]. In Poland these fishes are reared mainly in ponds together with common carp as additional fish on in the cages using heated water from power plants. There is no existing farm, which would aim in mass rearing of goldfish under controlled conditions. A lot of goldfish forms, especially most expensive, can be reared only in closed systems. From this reason, the production technology of rearing material must be done out of necessity. There are a lot of problems connected with rearing during first few weeks, which influenced on fish survival and growth rate.

The aim of this study was to carry out the mass rearing of goldfish larvae and juveniles under controlled conditions and to define the influence of fish density and food regime on survival and growth rates.

MATERIAL AND METHODS

Spawners
Goldfish spawners, about 50 specimens, were collected from two hatcheries: Department of Lake and River Fisheries in Olsztyn and Polish Academy of Science in Gołysz. Fish were from ornamental: “oranda”, “telescope” (broadtail) and “veiltail” forms, all very similar in body shape.

Spawning and egg incubation
Larvae were obtained after semi-artificial spawning. The broodstock was kept in special 1000-l tank equipped with regulation of temperature and photoperiod [8]. The spawners were stimulated using hCG (human chorionic gonadotropin) at dose 1000 IU kg^-1. It was a single dose, the same for male and female. After the injection spawners were transferred into the spawning tanks. There was 200 dm³ aquariums placed inside with mesh substrate (plastic screen, with the length of eyes – 5mm), on which fishes laid eggs. The spawners were released into the each spawning set – one female and two males. The water temperature after the injection was gradually raised from 22 to 27°C. After 10 – 12 hrs of the hormonal injection the spawning ensued. The incubation of the eggs in all the aquariums lasted for 48 hrs. Fish started to swim after next 48–72 hrs.

Fry rearing
The hatch was taken care for the next two weeks in aquariums, in which the spawning had been held. When the fishes had started to swim, the plastic screen was removed from the tanks. The fishes were feed with artemia naupli twice daily. Temperature was still constant 27°C. The light was switch on 18 hrs per day. Tanks were cleaned twice daily and dead fish were removed. Some water parameters, such oxygen and ammonia level, pH and temperature were daily noted.The fry rearing was ended after two weeks when fish had mean weight 0.15 g.

Initial rearing
Initial rearing was performed for chosen the best feeding regime. Goldfish larvae after two-weeks of fry rearing were moved to 200 dm³ aquaria at stocking density 500 specimens per tank. Fish were divided into three groups: A – feeding with natural food (frozen zooplankton), B – feeding with mixed (dry and natural) food, and C – feeding with commercial dry carp pellets (Aller Moller). The rearing was carried out 4-weeks. All rearing procedures were the same as in fry rearing. Experiment was made in duplicate.

Mass rearing
The two-weeks-old larvae were moved into 1000-l tanks. Each tank was equipped with devices for aeration, water temperature and daylight period regulation [8]. The temperature of tank-water was 26°C, tributary of the water was 3 dm³ min^-1. The tanks were lighted for 24 hours per day. There were automatic feeders over the tanks used for offer food. Fish were fed ad libitum. All rearing procedures were the same as during fry rearing.

The fishes were divided into four groups:

Group 0 – (negative control) 1200 items per tank, fed with dry commercial pellet (mixed carp and trout starters),
Group 1 – 1200 items per tank,
Group 2 – 1700 items per tank,
Group 3 – 3700 items per tank.

The fishes from the control group (“0”) were feed only with dry commercial diet. The fishes from the rest groups were feed with mixed food: commercial diet, frozen plankton and in the end of rearing period also frozen chironomid larvae was offered. Total time of breeding fish in this experiment was 6 weeks. Experiment was made in duplicate.

Statistics
Statistical differences between the groups (length and weight) were analyzed using the Duncan’s multiple range test with the significance level 5% (p < 0.05).

RESULTS

Water parameters during fish rearing were excellent. Dissolved oxygen level was over 6 ppm; ammonia was not detected (< 0.1 ppm); pH was between 7.3–7.7.

Initial rearing
During first two weeks of rearing goldfish larvae, the survival was excellent (over 98%). Fish fed mainly with Artemia sp. naupli grew fast. The mean fish weight of the two-weeks rearing period was 0.15 g. Much differ results were obtained after four-weeks initial rearing, where different food regimes were tested (Table 1). The best culture results: weight growth rate and survival was observed in groups fed with mixed food. The worst result, especially in the case of survival was noted when only dry food was offered to fish. Fish fed with natural food showed excellent survival but growth rate was much slower than in groups fed with mixed food. For this reason for mass rearing this last kind of food was chosen.

Table 1. The results (mean± SD) of initial, 4-weeks, rearing prepared for chosen best feeding conditions for goldfish larvae

Parameter/group	A – natural food	B – mixed food	C – dry pellet
Initial weight (g)	0.15 ± 0.1	0.15 ± 0.1	0.15 ± 0.1
Initial total length (cm)	1.6 ± 0.1	1.6 ± 0.1	1.6 ± 0.1
Final weight (g)	0.89 ± 0.22 b	1.32 ± 0.27 a	0.67 ± 0.19 c
Final length (cm)	3.2 ± 2.7 b	3.8 ± 3.3 a	2.9 ± 2.2 c
Survival (%)	98.5	98.2	3.6

Data in rows marked with the same letter did not differ statistically.

Mass rearing
After three weeks of breeding high mortality (30 ÷ 40% of the initial stocking density) was observed in groups “0”. During next week all the fishes died. After the section, the big amount of a fat discovered in the bodies all around the inner organs were observed. The highest survival rate was noted in group 1 – 88.0%. A little lower rate, but without statistical difference, was observed in group 2 (86.5%). Much higher mortality was observed in group 3, where only 63.2% of fish were survived. Also the growth rates (length and weight) are quite similar in groups 1 and 2 (Fig. 1 and 2). Lower density in group 1 caused more even growth without delayed specimens, but also without statistically significant differences. The growth rate was the slowest in the group 3. In this group the fish mass was getting worse in the last three weeks of rearing. It was not hard to notice a significant difference in fish’s size, what was decreasing a total mass in measuring. The decay of size was shown in the Fig 3. Also in fish from group 3 the cannibalistic attacks were observed in the last two weeks of the experiment.

Fig. 1. The growth rate of goldfish mass (mean ± SD) during intensive rearing in different densities

Fig. 2. The growth rate of goldfish length (mean ± SD) during intensive rearing in different densities

Fig. 3. The size schedule of goldfish from two stocking densities

DISCUSSION

During fast developing of intensive finfish culture in last years some bottleneck are visible. One of them is successful spawning in captivity. Second one, although important, is first few weeks of rearing larvae and juveniles. The presented last might be prepared under different conditions, i.e. ponds, cages, water-closed systems. The rearing the larvae and the juveniles under controlled conditions is the main method, and one of more important, of get the fish-stocking material of many species of fishes. During this process two problems usually occurred. The solution to these problems guarantees the success. The first of them is fish feeding. Natural environment gives food to the larval stadium. Controlled rearing requires hard finding natural food, or replacing it with commercial food. Hutchings of many cyprinids, i.e.: common carp, common tench and asp during first days of intensive feeding require natural food. These were described by Wolnicki and Górny [11], Kujawa et al. [7], Kujawa [6]. During feeding this fishes with commercial food there is a notice lack of appetite, grow stopping, lowering of immune to diseases and high mortality. The barb and the salmon are the only fishes, with can be feed with commercial food [12,10,6] . This problem was solved by popular artemia [1]. For the sake of the naupli size there is a need to apply this food only during first weeks of breeding. The size of fishes, which are getting bigger, requires using suitable for rates. It could be commercial food, but in case of goldfish it occurred that feeding those fishes with this food is usually unsuccessful. Supply the diet based on commercial and natural food it wills good effects. It happens in case of goldfish as well as in case of many others species [7,13,6].

Another problem is to give the optimal size of density during mass rearing. The target of every fish-farmer is to achieve fisches in similar sizes and low mortality during rearing. This problem was solved in case of many commercial species (salmon, common carp) as well as uncommercial species (burbot, dace, ide, asp, vimba bream) [6]. This study explains this matter in accordance to goldfish. It occurred that size of density is connected with the grow rate and mortality of fishes. The optimal density is about 1200÷1700 items of about 1.5 cm TL per cubic meter. The fishes should be fed with mixed food (commercial food with frozen plankton).

CONCLUSIONS

1. The best growth rate of goldfish was noted when mixed food was offered.

2. The highest growth rate was observed at lower tested stocking density.

3. During rearing of goldfish juveniles the cannibalism phenomena was noted.

REFERENCES

1. Bryant P., Matty A. J., 1980. Optimisation of Artemia feeding rate for carp larvae (Cyprinus carpio L.). Aquaculture 21, 203-212.

2. Czaplicka M., 2003. Rozród i gynogeneza karasia ozdobnego (Carassius auratus auratus) [Reproduction and gynogenesis in goldfish (Carassius auratus auratus)]. MSc Thesis, UWM, Olsztyn [in Polish].

3. Gouveia L., Rema P., Pereira O., Empis J., 2003. Colouring ornamental fish (Cyprinus carpio and Carassius auratus) with microalgal biomass. Aquaculture Nutrition 9, 123-129.

4. Kaiser H., Endemann F., Paulet T.G., 2003. A comparison of artificial and natural foods and their combinations in the rearing of goldfish, Carassius auratus (L.). Aquacult. Res. 34, 943-950.

5. Kestemont P., 1995. Influence of feed supply, temperature and body size on growth of goldfish Carassius auratus larvae. Aquaculture 136, 341-349.

6. Kujawa R., 2004. Biologiczne podstawy podchowu larw reofilnych ryb karpiowatych w warunkach kontrolowanych [Biological background for rearing reophylic cyprinid larvae under controlled conditions.]. Rozpr. Monogr. UWM, Olsztyn [in Polish].

7. Kujawa R., Kucharczyk D., Mamcarz A., 1998. Podchów wylęgu bolenia (Aspius aspius L.) i jazia (Leuciscus idus L.) w warunkach kontrolowanych na pokarm naturalnym i paszy granulowanej (w: Karpiowate ryby reofilne) [Rearing fry of asp (Aspius aspius L.) and ide (Leuciscus idus L.) using natural and artificial food under controlled conditio (in: Rheophilic cyprinid fishes)]. Eds. H. Jakucewicz, R. Wojda. Wydaw. PZW, Warszawa, 71-77 [in Polish].

8. Kujawa R., Kucharczyk D., Mamczarz A., 1999. A model system for keeping spawners of wild and domestic fish before artificial spawning. Aqacult. Engineering 20, 85-89.

9. Stępniak P., 2001. Masowy rozród i podchów narybku karasia ozdobnego (Carassiu auratus auratus) [Mass reproduction and rearing of goldfish juveniles (Carassiu auratus auratus)]. MSc Thesis, UWM, Olsztyn [in Polish].

10. Wolnicki J., 1997. Intensywny podchów larwalny i młodocianych stadiów brzany Barbus barbus (L.) na suchych dietach komercyjnych [Intensive rearing of larvae and juveniles of barbel Barbus barbus (L.) using dry artificial diets]. Rocz. Nauk. PZW 10, 19-21 [in Polish].

11. Wolnicki J., Górny W., 1993. Temperatura optymalna dla wzrostu młodocianego bolenia Aspius aspius L. oraz brzany Barbus barbus L. [Optimal temperature for growth of young asp Aspius aspius L. and barbel Barbus barbus (L.)] Kom. Ryb. 2, 9-10 [in Polish].

12. Wolnicki J., Górny W., 1995. Survival and growth of larval and juvenile barbel (Barbus barbus L.) reared under controled conditions. Aquaculture 129, 258-259.

13. Wolnicki J., Myszkowski L., 1998. Kontrolowany podchów wylęgu klenia i swinki na paszy – wylęg podchowany jako materiał obsadowy (w: Karpiowate ryby reofilne) [Rearing fry of chub and nase under controlled conditions – reared fry as stocking material. (in: Rheophilic cyprinid fishes)]. Eds. H. Jakucewicz, R. Wojda. Wydaw. PZW, Warszawa, 79-84 [in Polish].

 

Accepted for print: 07.01.2008

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Sławomir Krejszeff
Department of Lake and River Fisheries,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-718 Olsztyn-Kortowo, Poland
email: s.krejszeff@wp.pl

Paweł Stępniak
Gosławice Fish Farm, Poland
Rybacka 2, 62-505 Konin, Poland
Phone: +48 89 523 44 36

Dariusz Kucharczyk
Department of Lake and River Fisheries,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-718 Olsztyn-Kortowo, Poland

Andrzej Mamcarz
Department of Lake and River Fisheries,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-957 Olsztyn, Poland
phone +48 89 523 33 88,
fax +48 89 523 39 69
email: mamcarz@uwm.edu.pl

Roman Kujawa
Department of Lake and River Fisheries,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-718 Olsztyn-Kortowo, Poland

Katarzyna Targońska
Department of Lake and River Fisheries,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-718 Olsztyn-Kortowo, Poland

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