Hi, I’m Syikin,. Welcome back to our channel, last episode
we have explained about why we should do mud crab farming. If you haven’t watched the previous episode,
you can find the link at the description. In this episode, I'm going to talk on the
biology of mudcrab. This is Zarif, my colleague and he will be
showing you the crabs today. Mudcrab consist of 4 species which are first,
Scylla tranquebarica. This species is commonly wrongly identified
as Scylla serrata. Their claws are usually dark brown or purple
violet in colour. Scylla tranquebarica. is commonly found in
India, Malaysia, Indonesia and Philippines. In our systems, this species will dominate
the inventory.Second, Scylla paramamosain which is commonly known as the green mudcrab. They are commonly found in Vietnam, Cambodia,
China, Malaysia and Indonesia. You can see that the colour of their shells
is brighter. Third, Scylla olivacea. It is easy to identify from their red-coloured
claw. Commonly found in Malaysia, India, Bangladesh,
Indonesia and Philippines. This species can easily be identified by their
orange to red claw colour. Fourth, Scylla serrata species and also known
as the giant mudcrab or the Sri Lankan crabs. Scylla serrata is found in Australia, Sri
lanka, Philippines and Indonesia. This species is shown by their blue-ish claw
but using colour to identify this species is not recommended. Usually we identify this species by looking
at the pattern at their legs. However, did you know that each species can
grow different in size? For Scylla serrata, they can grow bigger than
1 kg in size. For scylla olivacea, they do not seem to grow
beyond 800 grams. For scylla tranquebarica, they can grow up
to 1kg in size .For Scylla paramamosain, they can only go up to 600 till 700 grams. Previously in our inventory, the largest mud
crab recorded was for Scylla Serrata, which the weight was at 1.3 kg. Moving on to the cannibalism parts of mud
crabs. Cannibalism has an impact on the stocking
density. High stocking density can lower the survival
rate due to cannibalism. The higher the density the higher the cannibalism
observed. Generally, immediately after molting, the
crab is vulnerable to cannibalism. Due to the softness of their body, crab are
being easily attacked by other crabs. Sudden death of crab was also observed due
to their inability to molting or we call it as molting failure. Unsuccessful molting and cannibalistic nature
of mud crab were the major cause of low survival. Moving on to the sexing of the crabs and price
variation As for juveniles, male and female mud crab
are difficult to identify, but when they matured, the difference is the abdominal flap of female
is much broader than male and become heavily pigmented when the female reaches maturity,
the other difference is the size of the male claw is bigger compared to the female.Scylla
serrata is prized for its big and the sweetness in their meat. It can fetch a premium of 6-7 USD extra for
these qualities in region Singapore, Hong Kong and Malaysia.In overall, the B2C price varies
according to the size, for 100-200 gram is RM 60 (USD 14), 300-400 gram is RM70 (USD 16) and 500-600 gram is RM 90(USD 21). Now we will demonstrate how to differentiate
water crab and meat crab. For those who are not familiar with our channel,
water crab is the crab that has less or almost empty meat in their shell. The difference between water and meat crab
can be identified by pressing the crabs shell. For females, press both the upper top of the
shell near the eyes and if it is flexible enough to move inward it is water crabs. For males, press both the bottom center parts
of the shell near legs joint and if it is flexible to move inwards it is water crabs. But if both male and females cannot flexibly
be pressed, they are meat crabs. If you plan to conduct mud crab farming, you
will need to understand what are the feeding preference of the mud crab. You can feed them with trash fish. Trash fish is commonly used throughout India,
Bangladesh, Philippines, etc. Depending on the size of the crabs, the fish
are processed and cut into smaller pieces and fed to the crabs. In our farm, we use a machine to cut our fish. As you can see, blood from the fish acts as
an attractant to the crabs, and crabs rely heavily on chemoreception that detects changes
in water chemistry. Most farm operators prefer trash fish for
reasons associated with availability and cost. Some people said that when the crab is dead,
it cannot be eaten as it will release toxin into the body. Crabs are usually consumed alive but when
they are dead, they still can be consumed with the correct way of storing within a certain
time frame. Sometimes when farm operator observed a weak
crab, the first step we need to do is immediately remove the crab from the system, and store
inside the freezer. if the crab are stored properly, it is ok. just like chicken or beef
which need to refrigerated after slaughtering. In conclusion, the biology of mud crabs such
as their species background, origin, sex, behavior is related to the marketing price
itself, hence having a deeper knowledge of the biology of mud crabs can be a good reason
to start up a business. In the next episode we will be discussing
why RAS vertical farming was introduced? If you have any questions, do drop in the
comment section. We also provided a link to download an eBook
which you can download for more information on mud crab vertical farming.Don’t forget
to subscribe and we hope to see you in the next episode.
