Mud crap Aquaculture or crab farming is commercially viable but capital intensive. Farmers require expert knowledge on crustaceans, nutrition, breeding culture, pond management. Other considerations are marketing, processing, crab breeding, and grow out. They attract premium price have good export potential, domestic applications.
List of Edible Crabs
Edible crab variety are red claw, green mud, Dungeness, Blue and Horseshoe crab. Others include stone crab, peekytoe (Cancer irroratus), snow crab, king crab, hard/soft shell mud crab.
Stone crabs are a prized delicacy have prominent large hard claws found in Florida United States of America. It takes one year six months for a 2.7 ounce claw to regenerate while processing involves boiling, freezing.
Male king crabs are primarily harvested for their large size and delicious meat. An average male weigh 20 -25 pounds. Cancer magister or Dungeness crab weigh 2 to 4.5 pounds have succulent pink flesh are 6 inches long while horseshoe are small prehistoric creatures.
- Red claw
- Green mud
- Horseshoe crab
- Stone crab
- Peekytoe (Cancer irroratus)
- Snow crab
- King crab
- hard/soft-shell mud crab
Best Crabs for Commercial Production
The best crabs for commercial production are the soft-shell mud crabs, hard-shell mud, stone crabs, and king crabs.
|Blue Crab||3 to 4 Inches|
|King Crab||25 pounds|
|Dungeness||4 pounds, 5 inches|
|Stone Crab||A Single claw weighs – 2.7 ounces|
Mud Crab Farming Grow Out System
Cannibalism is a big problem in grow out pond system and they fight among themselves for dominance. There are three basic types of culture earthen pond, cage or pen. Earthen ponds are applicable to brackish water, pen or pond used in mangrove.
Growing Mud Crabs
Crab aquaculture require application and licensing. Farming includes the hatchery phase, nursery phase and growing phase. Another thing to consider is farm size, design, stocking rate, water quality, temperature and feeding.
Things to Consider in mud crab farming
- application and licensing
- land size
- hatchery phase
- nursery phase
- growing phase
- pond design
- stocking rate
- water quality
Crab farming is capital intensive and you need operational license. To source funds approach commercial or trade bank for loans.
Make sure the loans are long termed, low interest loans. You need collateral, guarantor, one third startup fund and account in the bank. Other fund sources are angel investors, partnership, venture capitalists.
Mud Crab Aquaculture
Hatchery requirements for S,serrate king crab is described in this section. However the method is applicable to commercial production of Scylla serrate, S.olivacea and S.tranquebarica.
Select a fully matured female with developed ovaries. Crab should be mature, free from deformities, complete limbs. The female crab will have orange ovaries then poor water on them every five minutes for a duration of half an hour.
Prepare a basin with 150 ppm formalin, disinfect then introduce them to the pond. For further detailed method visit this site seafdec.org,ph
Intensive culture reduces the marketable size in record time. It takes post-nursery crabs 2 year to mature in natural conditions while intensive culture reduces the full maturity to 7 months.
Stocking rate determines the survival, growth rate of the crustaceans. Cannibalism is a serious problem with high stock rate. Stock about 1500 crabs per h, rate of 1 – 2 per square meter in earthen pond. Commercial farmers use intensive culture, feeding, pond design to increase production.
Mud Crab Farming Design
The type of system will determine the pond design. Large farms deploy high density recirculating system and earthen pond for faster growth and better efficiency. The earthen ponds are often located in brackish water.
They eat small crustaceans, shellfish in their natural environment. However farmer feed them dried pelleted formula, fish waste and trash fish.
- Small crustaceans
- Dried pelleted formula
- Fish waste
- Trash fish
Proper water management is key to farm success. Ideal salinity is 15 ppt -25ppt (parts per thousand), temperature between 20°C and 32oC. Larvae are highly sustible to salinity and temperature changes while mature/juvenile more tolerant.
- salinity is 15 ppt -25ppt (parts per thousand)
- temperature between 20°C and 32oC
During moulting cannibalism is prevalent due to soft exoskeleton. The new larger shell then expands and hardens accordingly. They are very vulnerable during this period and easily attacked or killed.
Adequate shelter is needed for them to hide. Hiding places are introduced through short length piping, onion bags, car tyers, and masonry blocks. The introduction of these material makes pond management rather difficult however they improve survival rate, productivity, and growth.
There is not much research on mud crab diseases on commercial production. However antibiotic use in aquaculture have significant impact on human consumption of crustaceans farmed under this conditions. Other considerations are fungal, pathogens, viral diseases or exotic diseases.
Parasitic infections are metazoan, Sacculina sp. we have luminescent bacteria disease, filamentous bacteria disease, red sternum syndrome. Fungal diseases include Halocrusticida sp., Lagenidium sp, Atkinsieilla sp.
Viral diseases are renovurus, baculovirus infection, muscle necrosis virus. They are also susceptible to injury, stress, rust spot shell disease, deformities and toxicity.
- luminescent bacteria disease
- filamentous bacteria disease
- red sternum syndrome
- Halocrusticida sp.
- Lagenidium sp
- Atkinsieilla sp.
- baculovirus infection
- muscle necrosis virus
- rust spot shell disease
Marketing involves direct or local marketing, international sales. Crab produce export is common in many countries with adequate shoreline for production. Local markets are households, fast food outlets, restaurants, hotels.
- Market women
- Food vendors
- International market
- Meat processors