Mangrove crabs are called what they are due to their natural habitats – mangroves – and their large exteriors. Additionally, mangrove crabs are also mobile on both land and sea. As for their exterior, male mangrove crabs have significantly larger claws in comparison to their female counterparts.
These unique crustaceans are also a popular protein option of your favourite seafood dishes, due to their rich taste and high levels of nutrients. The demand for this specific crab meat has grown overtime, which has lead opportunists everywhere to start their own mangrove crab farm.
So, if you’re interested or are willing to learn a little more on the profession, it is wise that you invest or capture your own starting pair. If you’re thinking of doing the latter, be sure to read through this article to find out the 13 factors to consider when hunting mangrove crabs.
1. Living Spaces
First and foremost, future breeders should locate and designate a place where you could place your hunts in. Breeders should construct a pond with the depth of 0.8-1m, salinity of 15-30ppt, layered with chalk or dirt, and fenced with sturdy material about 1.5-2m in area. Though the size may vary according to each farm, breeders should manage to estimate a good amount of living spaces that allows them to move and live comfortably in.
2. Consider Natural Causes
After designating a good living space, the next step is to fill in the pond with organic and natural additions. Fill the pond with clean and sterile water, and allow a good amount of feed around the premises for them to feed. The quality of their living spaces will directly affect their health, so it is wise that breeders consider the following points:
- Location is far from pollution and potential predators
- Living spaces is easily accessible by professional breeders to monitor their health, and has a good sense of responsibility
- Feed intake around the premises should be monitored to avoid over feeding and under feeding
- Breeders should monitor population so that the harvesting rate does not overweigh the reproduction rate – and vice versaC
As most living things are, domesticating and capturing wild animals at their infant age is much easier than targeting their adult counterparts. From the very first steps, and on to hatching, breeders should carefully monitor expecting females’ offsprings on their overall health and nutritional intake. Ideally, a breeder’s mangrove crab farm should produce offsprings carrying these traits:
- Great hand-eye coordination and reflexes
- No physical disabilities
- Good reproductive system (9-10cm in width for females, and 11cm for males)
- Pregnant females do not catch fungal infection, or have concerning brown spots on their exterior
4. Designating Space for Birth
After familiarising with a mangrove crab’s reproductive system and patterns, breeders should anticipate when the day comes – start with providing a bucket or any other container that provides a safe space for birth.
First, breeders must sterilise the container to ensure that it is free from lingering bacterias and diseases. Dry the container in direct sunlight for 2-3 days, then customise the environment to mimic their natural habitat. Add 15cm layer of sand on the surface, and fill in 10-20cm of water into the container. The size of the container depends on the size of the expecting mangrove crab, so be sure to monitor and estimate the right amount of space.
5. Speed Up Reproductive Organ Growth
Some breeders are in a state of urgency to build a large farm of their own, whilst their farm’s reproductive age may not have been fully developed yet. To speed up the process, breeders are advised to cut off one of their eyeballs that contains a vein that slows down the growth of their ovaries.
Before reproducing and spreading their offsprings, the expecting crab should take time to familiar themselves with their new environment. To help with this, breeders should place the expecting female with other crabs with a male to female ratio of 1:2, to encourage socialisation. During pregnancy, breeders should feed their farm twice a day (morning and afternoon) with doses that weighs 15% of their weight a day. Gradually decrease the amount of deed to 5% of their weight days before the expected date. More so, it’d also help to replace and sanitise their living space waters from harmful bacterias.
6. Caging Method
To optimise the amount of offsprings that your crabs are able to produce , breeders could adopt two different methods which lists the following:
- Caging Method: construct a 1.7m cage made out of sturdy bamboo trees. Caged a pair of crabs within the tool together, which would then allow said crabs to socialise and copulate faster. Be sure to provide the right balance of enough space and confinement that is intimate and not claustrophobic.
- Floating Cage Method: A floating cage would serve the same purpose as the ordinary caging method, but it is well adjusted more to their natural environment. The floating cage method is less stress inducing than the ordinary caging method, and it is less confined.
Generally, mangrove crabs should be able to produce within 10-15 days after copulation. They are also expected to reproduce anytime soon if the female crabs reach up to 150 gr in weight.
7. Gaining Weight
Underweight crabs usually an alerting sign for their overall health. This is usually an indicative sign that said crabs are not receiving the needed daily nutrients. To help solve this, breeders would have to monitor their feeding intake and observe their socialisation patterns. Most crabs might lose their weight under stress or when fighting with their peers, so breeders should separate feisty crabs from the rest.
8. Egg Hatching
One expecting mangrove crab can produce up to 1-2 million eggs with a 95-98% hatching rate, and only take up to 10-12cm of space. Mangrove crabs keep their eggs within their abdomen for 10-12 days before they hatch. Their abdomen supports the right temperature for their birth, which has the salinity levels of 31-32 and around 26.5-29.5 degrees in temperature.
When expecting, be sure to lay the mother in a glass container to avoid getting attacked by predators alike. Be sure to monitor the air and water flow, to ensure that no harm is done around the premises. Once the expecting crabs has laid their eggs, wait for them to brown in 7-8 days and the relocate them to a safer environment.
Some breeders would harvest the eggs then and then. However, in order to grow your farm, breeders would would raise at least a partial of their eggs into a cone-shaped glass container – that holds up 300-500l in volume. Fill the cone shaped glass container with sea water that has 32-35 ppt salinity levels and 29-30 degrees celsius. Carefully monitor their growth to prevent any fungal infections from happening. In the unfortunate event that said crabs have been infected, mix in 10ppm of formula in the waters for 24 hours to sanitise the area.
9. Raising Larvas
Hatching eggs would lead on to the next step: raising larvas (Zoea). As smart breeders, it is your responsibility to move the zoeas in a fiber glass container that inhabits 10-30 zoeas per liter of water. At this stage, breeders could feed zoeas organic feed such as rotifer, artemia, and small shrimps.
Since they are newborns, the initial quality of their water pond should be heavily monitored to avoid getting infected with any fungal and other diseases. Routine change of said water should be done on 25% of its overall quantity during the third stage of zoea development, and then increase to 30% during the fourth stage of zoea development.
10. Nutritional Feed
Mangrove crabs’ diets has a relatively low investment rate in terms of finance and time wise. Breeders could feed mangrove crabs organic feed such as small fishes, chicken organs, cow and goat skin, small snails, and the many alike. Small fishes are a popular option amongst breeders, for their convenience and high packed nutrition.
However, if breeders are opting for a hassle-free diet, they could ask medical professionals to prescribe them with nutritional pellets and extra supplements. Generally, the prescribed dose for extra supplements would be 15% of each individual crab’s weight.
11. Basic First Aid
At any given time, breeders should be able to provide basic first aid care to their farms. In doing so, be sure to regularly change their pond water and sterilise it with antibiotics to preserve the quality and prevent any potential infections and diseases. More so, breeders should also be able to differentiate between a healthy crab with their unhealthy counterpart, in order to isolate the sick crabs from the rest and provide extra curing care.
12. Speed up Growth
In order to grow good quality crabs, breeders would utilise the pond system to maximise their optimal growth. Clear, sanitise, and regularly change their feed to avoid any diseases and bacterias fostering in the areas with special non-toxic cleaning formula. Be sure that the pond water reaches 27-28 degrees in temperature, 10-15 promil salinity levels, 6.5-8.5 pH acidity levels, and 5.5ppm oxygen level. To prevent major stress, be sure to sunbathe your crabs to receive the right amount of dopamines and minerals that sunlight can provide.
13. Harvesting Mangrove Crabs
When the time comes to harvest them, you’d have to place your mangrove crabs out of water. Though this is a necessity for the sake of mobility, this might dry out their bodies – which could indirectly affect their market value due to being dehydration. To prevent this, be sure to spray your mangrove crabs with water once in a while to maintain their hydration.
To easily pack them without the hassle and fear of crab attacks, breeders would prepackage their harvest by gently binding them with string. However, smart breeders would do this as gently as possible – to prevent stress that could reduce the overall quality of crab meat. Breeders should also remember to clean off any lingering messes by dipping them in sanitised water and letting their messes slide off naturally.
So there you have it, 13 factors to consider when hunting mangrove crabs. Note that, however, these are just general points and further prior research is advised. Remember to consult experienced breeders and medical professionals if you are ever in doubt: to prevent any potential further damage.