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PRODUCTION OF BABY SWIMMER CRAB Portunus pelagicus IN THE PONDLisa Ruliaty, Darmawan.A and Agus Basyar A.HMAIN CENTER FOR BRACKISHWATER AQUACULTUREJEPARA - 2016

INTRODUCTION (1)Swimmer crab included in to important export comodity after shrimp and fish.Indonesian ministry regulation no.1 on year 2015 regarding prohibition of catching lobster, swimmer crab and mud crab. The solution is to do aquaculture in the pond, that mean is need swimmer crab seed (juvenile/baby crab)Unfortunately, the technology to produce baby swimmer crab up till juvenile size (baby crab) in massive scale still not developped yet. One of the problem is the survival rate still low.

INTRODUCTION (2)Engineering of production baby swimmer crab on cultivation in hapa and controlled container has been done with quite good result.

Its showing that production baby swimmer crab in the pond can be done also.

Purpose

Production juvenile size (baby crab) of swimmer crab with modular system hopped able to simplify the technology in swimmer crabs hatchery.It can produce baby swimmer crab in bigger size continuously.

1. Material :

Female mature ovaries of swimmer crab.Natural food for larvae (Chlorella sp, rotifera and artemia)Food for Megalopa stage (smooth shrimps without shells)Food for Crablet (minced fish)Chemical material (saponin and moluksida)Organic fertilizer

Female Mature Ovaries

Feed for Swimmer Crab HatcheriesChlorella spMinced ShrimpArtemiaRotiferaCrab instarMegalopa StageZoea Stage

2. Equipment :

Hatching tanksArtemia Hatching tanksLarval tanks with capacity 5 m3. Ponds with large 500 m2. Hapa net with size 1 m x 2 m (mesh zise 0,2 cm) Milling machineScissor and knifeFields equipment (equipment for aeration, bucket, beaker glass and water dipper)Monitorings equipment (microscope, beaker glass, refraktometer and thermometer)

METHODE:

Step 1: Larvae with first density 100 pcs/L spreaded in to Larval tanks with capacity volume 5.000 L as much 6 units. Larva tanks was completed with aeration equipment. We used sterile sea water with salinity 30-33 ppt for larval rearing of swimmer crab.We changed the water up till 20% every 3 days to take care the water quality of cultivation media. The larvae were feeded using rotifers around 10-15/mL starting from spreading day up till transfering day, depend on the treatment. Microalgae Chlorella sp have been given to rotifers with density 100.000 cels/mL.

METHODE:(continue.)Step 2 : Larvae in last zoea stage or in 8 days cultivation age in larval tanks then transferred to the ponds with large 500 m2 and medias height 60 -70 cm which has been prepared before.The pond preparation was done with the stages of drying, pest control and fertilization to grow plankton in the ponds. We put black gauze on the ponds drain to make the harvesting easier. The density of larvae which is spreaded in the pond was as much 2.500 larvae/m3 (2,5 pcs/L). We gave artemia with density 20 N/larvae/day in the first week. After the larvae zoea become crablet, we gave minced fish for their food, 2 times a day (in the morning and evening) as much 200 300 g/1.000 Crab/day (>200% from weight of biomass). In the first 10 days of cultivation, fish which was given have been smoothed using a milling machine and in further cultivation, the fish which was given have been cutted into small pieces..

METHODE:(continue.)

As controll of the Survival Rate as well as the baby swimmer crabs growth, we also put green hapa with measurement 1 m x 2 m as much 3 pcs in the pond. The controll hapa was spreaded larvae with density 2.500 pcs/m3 (as much 3.000 pcs/controll hapa) and the larvae has been cultivated using the same food.Sampling of weight baby swimmer crap on controll hapa has been done 1 week after cultivation then we converted it to calculate the food requirement while the total sampling of survival capability and the weight of baby swimmer crab have been done on the last day of treatment. Beside that, we also measured the water quality parameter.

Larval Rearing

Step 1Step 2

RESULT1. Survival Rate D-8Avg = 59,44 % 12,8 %

2. SR Baby Crab at the hapa No.of Hapa controlNum of larvae (pcs)Last amount (pcs)Survival Rate (%)130002297,6323000802,67330002207,33Avg176 845,9 2,8

3. Result of growth measurement, ie. long (mm) and weight (g) on cultivation Step 1StageRange of long (mm)Average of long (mm)Range of weight (g)Average of weight (g)Zoea-11.10-1.331.22 0,080.00320.0032 0.000Zoea-21.51-1.631.57 0.060.0043 0.00470.0047 0.005Zoea-31.53-3.092.09 0.610.0044 0.00 530.0048 0.003Zoea-42.75-3.373.05 0.180.0066 0.01030.0084 0.018

4. Result of measuring the growth of carapaxs width and weight on cultivation Step 2 in controll hapaAge of cultivation (days)Average of carapaxs width (cm)Average of weight (g)D-70,64 0,081,38 0,03

D-140,92 0.151,65 0,25D-211,97 0,312,44 0,55

D-282,62 0,524,13 1,52

5. Range of water quality on cultivation Step 2ParameterRangeReferenceTemperature ( oC)27,10 28,2026-32 a dan cSalinity (ppt)30 3230-33 ppt cAcidity7,20 - 8,185,5-8,5 aDO (ppm)3,19 6,32>3 mg/L aAmonia (ppm)0 0,08