TEAM MEREA
Mr G. Le MOULAC
The reproduction of Penaeus japonicus has been studied for years. The Medterranean climatic conditions in France favours the rearing of this species.
The production of post-larvae in hatcheries is easy. The pathological problems (black branchiae disease) cause by maintaining brood-stuck in captivity, have been resolved. Survival rates for broodstook are good at the end of a nine month period (60 %). Maturation is obtained at 18° C. Spawning takes place when the température is raised abruptly to 25° C. Larvae rearing is carried out at 26° C while supplying mono specific algae cultivated in algae rooms and Artemia nauplii when these reach 23 stage. The final density is around 100 p3 per liter. Pre-fattening is carried out at 23°C. The feed comprises of Artemia nauplii and deep frozen feed. The initial density is 10 p3 per liter and there is a survival rate of 70 % at P23 stage.
These established facts permits the proposition of an intensive production model in hatcheries and the technico-economic study relative to this. The definition of the productive cost gives the opportunity of having an efficient programmation tool at disposal, to increase productivity. A 20 % increase on the production cost of post-larvae has been obtained, by modifying the feed sequence.
N/Ref: GLM/MPD
No 85.05.306
INTRODUCTION
The production of P. japonicus post-larvae is no longer a hidering factor to the development of shrimp culture in France.
The technico-economic study shows clearly that this production is profitable. The techniques employed show good results. The progress envisaged now is at the increase level of productivity which should cut down the production costs of post-larvae.
The first productivity increases quickly obtained concerned feed, by optimizing the output and by employing low cost feed.
DESCRIPTION OF THE PRODUCTION CHANNEL
1) Stocking in tanks
Brood fish stocking during winter demands the abidance of a certain number of rules.
1.1. The origin of the brood fish (lagoons):
To have at disposal fish which do not need to be fattened during winter.
1.2. The temperature to be kept is 180° C which limits the growth of the animals.
1.3. Survival depends on the regular drainage of the tanks.
1.4. Fresh feed : mussels, crab, calmar.
1.5. dividing up of animal stock :
2 females for 1 spawning with a ratio of 7 females for 3 males and a density of 15 animals/m2.
2) Spawing
Mature animals at 18° C are placed into a tank at 25° C without having the peduncle oblated.
- Sand bottom, important renewal, 180000 nauplii spawned per female.
- Spawning all year round.
3) Larvae rearing
At high density, starting 220 nauplii per liter which show a70 % survival rate at P3 stage.
3.1. The feed consists of unicellular algae :
- Chaetoceros calcitrans
- Phaeotachylum tricornitum
- Monochrisys lutherii, through out the whole period of rearing and Artemia nauplii from 23 stage onwards.
3.2. Feeble renewals of 10 to 20% per day until P3 stage is reached.
3.3. A constant 1000 lux light on the cylindro-conical tank of m3 by means of a 150 w spot light.
3.4. Anti-fungic control - Constant drip of treflan. Anti-bacterial control-Furazolidone from Z1 stage, every 48 hours until Mysis 1 stage is reached.
4) Nursery-Prefattening
4.1. Having 10 P3 per liter during 20 days. Survival is 70 %
4.2. The food consist of Artemia nauplii until P10 stage and from then deep frozen adult Artemia.
4.3. A 100% renewal per day
4.4. a temperature of 23–24° C.
5) Technico-economic study of the channel;
| Brood fish | Nauplii | P3 | P23 | |
| Animals | 11% | 75% | 36% | 26,5% |
| Heating | 27,5% | 10% | 6,5% | 11,5% |
| Pumping | 2,7% | 0,6% | / | 1,2% |
| Air | 0, 3% | / | / | 0,6% |
| Feed | 5,% | 15,5% | 16,% | 3,5% |
| Manual labour | 53,2% | 15,5% | 16,4% | 3,5% |
| Unitary price Tax free | 120,9 F/0 | 1,62/100 N | 9/1 000 P3 | 48/1000 P23 |
Table - Analysis of the production cost (1)
The facts established permit the economic study of the reproduction channel. The most important points in feeding are at larvae rearing and prefattening stages. Increases should be quickly remarked at these points.
6) Productivity increases
6.1. Prefattening
In substituting deep frozen Artemia by Daphnie which costs 11F/kg while the former costs 48 F/kg.
20% gain on the cost of p23.
| Brood fish | Neuplii | p3 | p23 | |
| Animale | 11% | 75% | 36% | 34% |
| Heating | 27,7% | 105 | 0,5% | 15,2% |
| Pumping | 2,7% | 0,6% | / | 1,5% |
| Air | 0,3% | / | / | 0,7% |
| Feed | 5,1% | / | 41% | 43,9% |
| Manual labour | 53,2% | 15,5% | 16,4% | 4,5% |
| Unitary price Tax free | 12o,9 F/o | 1,62/1 000 N | 9/1 000 P3 | 38/1 P23 |
Table 2 - Analysis of the production costs productivity improvements in prefattening
6.2. Larvae rearing
Survival of 60 – 70% (mixed algae in larvae rearing.)
30% gain on the cost of a P3
10% gain on the cost of a P23
| Broodfish | Nauplii | P 3 | P 23 | |
| Animal | 11% | 755 | 36% | 25,3% |
| Heating | 27,5% | 10% | 6,5 | 16,8% |
| Pumping | 2,7% | 0,6% | / | 1,8% |
| Air | 0,3% | / | / | 0,9% |
| Feed | 5,1% | / | 41*% | 50,3* ½ |
| Manual labour | 53,2% | 15,5% | 16,4% | 5% |
| Unitary Price Tax free | 120,9 F/O | 1,62/1 000 N | 6/1 000 P3 | 34/1 000 P23 |
Table 3 - Analysis of production costs improvement of productivity in larvae rearing
6.3. Prefattening
Compound dry feed. Conversion index = 3 unitary price = 30 F/kg
40% gain on the production cost
| Broodfish | Nauplii | P3 | P23 | |
| Animals | 115 | 75% | 36% | 46,1% |
| Heating | 27,55 | 10% | 6,5% | 30,8% |
| Pumping | 2,75 | 0,6% | / | 3% |
| Air | 0,3% | / | / | 1,5% |
| Feed | 5.,1% | / | 41% | 9,2% |
| Manual labour | 53,2% | 15,5% | 16,4% | 9,2% |
| Unitary Price Tax free | 120,9 F/O | 1,62/1 000 N | 6/1 000 P3 | 20/1 000 P23 |
Table 4 - Analysis of production costs improvement of productivity in prefattening
6.4. Evolution of gain on the production costs of post larvae.
A gain of 20% is remarked on the production cost of p23 post-larvae when deep frozen Artemia are subtituted by Daphnies.
A 10% gain follows with the use of an algae cocktail in larvae rearing.
A 40% gain can be scheduled in prefattening when granulars are employed.
| 1 | 2 | 3 | 4 | |
| Animals | 26,5 | 34 | 25,3 | 46,1 |
| Heating | 14,8 | 15,2 | 16,8 | 30,8 |
| Pumping | 1,2 | 1,5 | 1,8 | 3 |
| Air | 0,6 | 0,7 | 0,9 | 1,5 |
| Food | 56,5 | 43,9 | 50,3 | 9,2 |
| Manual labour | 3,5 | 4,5 | 5 | 9,2 |
| Unitary price T.F. 1 000 P 23 | 38 | 38 | 34 | 20 |
| Production cost % profit | 20% | 105 | 40% |
Table 5 - Analysis of evolution of gains in productivity when the feed sequence is modified
CONCLUSION
From this point on, the gains on production costs are obtained with brood fish by recovering and cryopreservating fertilized eggs or Nauplii, so allowing the use of broodstock the whole year round.
On larvae rearing and investiment (algae room) by the use of microparticles.
