In Rota, the locals consider the coconut crab a delicacy, and prices range from $25 for a 3” crab to $50 for a 6” crab. Twenty years ago, coconut crabs were abundant and actually littered the road. However, because of the increased demand from neighboring populations, the locals have harvested the crabs more often.
Now the wild crab supply is scarce. The practice of coconut crab farming using recycled food will help prevent the natural habitat population from being over-harvested and will give the coconut crab a chance to reproduce.
Through this project, I intended to raise coconut crab in captivity using recycled food. I constructed a crab pen 25’x25’ and 6’ deep. I collected 104 juvenile coconut crabs, all beginning at ½” in size. I labeled 20 of the crabs and closely monitored their growth and behavior.
I equipped the pen with two water ponds, one saltwater and one freshwater, each lined with hollow blocks to mimic natural habitat shelters. I also used top soil in half of the area for the crabs to use for hibernating and to change their exterior shells. The other half of the area was composed of loosened coral rocks about 4” in diameter, which they consumed to harden their exterior shells. I also included dead wood, loose debris, and cut grass to create a natural habitat.
Coconut crabs are omnivorous and willing to eat about anything, but seemed to prefer coconuts. Other food sources they willingly consumed include banana, papaya, sugar cane, noni fruit, breadfruit, watermelon, and raw meat.
Throughout the project, the crabs showed positive growth. When first captured, they seemed stunned and took about a month to recover and adjust to their new surroundings. According to our findings, our captive crabs grew between ½ and 2 centimeters per year. In maturity, they are about 6” across the main body and weigh between 4 and 5 pounds. They take about six years to mature.
It is important to cover the crab pen with a net to prevent iguana lizards from entering it and killing the crabs.
BENEFITS OR IMPACTS ON AGRICULTURE
This study shows that engaging in coconut crab production using recycled food is worthwhile and positive results are attainable. The domestication of this animal can alleviate the year-round over-harvesting by local poachers.
It will also enable people to venture into commercial farming and advance economically. Subsistence farmers can use the coconut crab as a food source if consistency in farming is implemented and maturity for harvest period is reached. The project also advantages for society and the local economy.
This project has been heavily advertised and made available by the CREES office at the Northern Marianas College and Department of Land and Natural Resources office. I have also been paid a number of visits by local farmers who seem impressed by the simplicity of the project.
REACTIONS FROM PRODUCERS
I have received much interest in my project by other farmers considering a similar venture beginning as subsistence farming, then moving on to eventual commercialization.
I recommend the government designate an exclusive zone where the coconut crab is not to be hunted, while other areas open up for seasonal hunting.
My project has been advertized in the Marianas Variety newspaper and in papers in CNMI and Guam.
The project was presented at a conference in Guam in October 2007, sponsored by Western SARE.