Throughout our research and experiences with mud crab aquaculture, we have encountered different myths and facts about them. Some of them are passed down through folklore, while some of them are by word of mouth, there are also facts and researches published on scientific journals. In this article we will be addressing some of these myths, verifying the facts to truly understand these unique creatures.
Fact #01- Mud Crabs are Nocturnal Creatures!
Mud crabs are most active at night. They usually forage for food and move about during the night. In the day, they prefer to hide in mud pits where they are safe from predators. As a result, most of the crab farmers will feed the crab early in the morning and late in the evening. Some farm operators even feed them suppers around midnight. Their activity and aggression level can be quite different from the daytime versus nighttime. Comparing our observation of the crabs in the morning, the actual conditions can be quite different at night. Most of the crabs that escape from their individual boxes occur during night time.
Fact #02- What are the soft shell crabs?
Similar to snakes, crabs have to shred off their shell (or known as the process called molting) in order to grow. Right after molting, the crabs will then proceed to absorb minerals from the water to harden their shells. If they are harvested before their shell hardens, they are known as soft-shelled crabs. Soft shell crabs can be produced in farms with mud crabs, blue swimming crabs, or any crabs in general. In Asia, soft-shelled crabs are commonly obtained by harvesting newly molted mud crabs. While in the United States, soft shell crabs (or known as peeler crabs) are harvested from blue-swimmers crabs.
Fact#03- A mosquito bite to the crab’s eye would not kill the crab.
The presence of mosquito will not threaten the livelihood of your crabs. It is commonly known that if the mosquitoes manage to sting the eyes of the crab, the crab will not survive. We have encountered farm operators going the extra mile to ensure no mosquitoes are near the crabs. Mosquitoes are attracted to warm blooded creatures, while crabs are cold blooded. Furthermore, some of the mud crabs, usually the broodstock used for hatchery production undergo a procedure called eyestalk ablation (where their eyes are cut off to stimulate egg production), and the crabs are able to survive this procedure.
Fact#04- Crab soup used for Dengue treatment
Apart from the festive demand for mud crabs, there is also demand for mud crabs for its therapeutic value. There are studies done by a Malaysian university state that the blood of the mud crab contains disease fighting abilities, especially for dengue and cancer. It has been a traditional belief, particularly among the Malays to cook soups using mud crabs as a remedy to cure and treat dengue fever. That is why mud crabs prices are always fluctuating within the year, where the highest prices occurring around Chinese New Year. Dengue fever outbreaks is also likely to increase the price of mud crabs in the local region.
Fact#05 -Watery crabs during full moon
The science behind molting have baffled scientists for many years, but it is generally accepted that most crabs generally molt in accordance of the lunar cycle. Check out our previous post on mud crab growth and molting here. The most popular period for molting is during the full moon, in which upon harvesting results in crabs that are watery in nature (lack of meat). Crab connoisseur would usually avoid eating crabs on the full moon to avoid eating sub-par crabs.
Fact#06- Mud Crabs probably would not like human flesh
Mud crabs are omnivores where their diets consist of slow moving creatures like shellfish. Check out our previous post on the top five feed for mud crabs here. Mud crabs are picky eaters, and prefers only fish that are fresh. There has been fears about mud crabs feeding on human flesh, but that have never been officially recorded. Chicken is probably the closest form of meat when it comes to mud crab feed, although this practice is getting less popular throughout the years.
Fact#07- Dead crabs are poisonous
In countries like the Philippines, Malaysia, and Indonesia consumers would not consider eating crabs that are not alive and jumping. Claims have been made about crabs meat turns into poison after dying. While in countries like Thailand and India, it is common for consumers to buy frozen dead crabs. In general, crab meat turns bad very quickly (similar to any chicken and beef) if left in normal room temperature after they are dead. If the dead crabs are frozen immediately and stored, it can still be consumed on a later date.
Hopefully this blogpost will help you in getting a better understanding of the mud crabs, and how to culture them successfully!