Grouper Culture Using RAS - Calculations 2

In my last posting, we finally able to calculate the maximum standing stock (MSS) of our RAS for production of 12mt/year of grouper fishes. We should also be able to calculate the average standing stock (AvStS) of our system by doing the averaging calculation from month 1 of full batches production (i.e month 12 from the beginning of the farmig) to certain period of farming, which is based on my last calculation, I used to up to 16th farming month of full circle production, i.e month 26th. Let we see the table below:

Standing Stock

So, the AvStS will be 6149 kg through out 16 farming months and represent about 51% from targeted production. In my last post we calculated the MSS was at 7264kg or 61% from our targeted production. Bear in mind of these figures, which we will use to find the design peak load (DPL) of our system for most variables in our system i.e. oxygen supply requirement, carbon dioxide production, ammonia-N production, bio-oxygen demand (BOD) and suspended solids production. 

The maximum food given in MSS situation will be 94.43 kg/day while the average maximum food given in average standing stock (AvStS) will be 79.94 kg/day. The oxygen requirement for each kg of food given will be 350g while carbon dioxide produced per kg of food will be 1.2 times higher than the amount of oxygen consumed which is equal to 420g per kg of food given (350g x 1.2 times). Based on these facts, during MSS, the maximum oxygen consumption will be 33.05 kg/day while in average standing stock situation the oxygen consumption will be  27.98 kg/day. We also able to know now that carbon dioxide production in MSS situation will be 39.66 kg/day (350g/kg of feed x 94.43 kg of feed) while in average standing stock situation (AvStS) it will produce 33.57 kg of CO2/day (420g of CO2/kg of feed x 79.94 kg of feed). So, up to now, we already able to calculate our maximum standing stock, average standing stock, feed requirements during MSS and AvStS, the oxygen requirement during MSS and AvStS and lastly we able to calculate the carbon dioxide production in both situations of MSS and AvStS.

In next posting, I wish to share how to calculate the ammonia-N production, BOD and suspended solid going to be produced in our system.

Grouper Culture Using RAS - The Basic Calculations

Last week I visited 2 fish farms that using  recirculating aquaculture system (RAS). Interestingly, both have changed their species to another newly introduced species that having higher price and in demand in the local market. I like their idea of changing the species when the need arise. Having a better priced species is the rule of thumb no 1 in our RAS considerations, but surely is not the only factor that we must consider. More interestingly, they were changing from marine water species to fresh water species. That is the extra benefit of RAS. We may change the “climatic” conditions of our farming system without need to change the location or even the equipments.

What shall we know about RAS before we design it? First, off course the species that we intent to culture, their requirement or acceptable water quality. Please get the information on the acceptable levels of dissolve oxygen (DO), carbon dioxide (CO2), ammonia (NH4⁺ /NH3), nitrite ( NO2 -), nitrate (NO3-), suspended solids (SS) and salinity of our chosen species. Some grouper species have different tolerant towards fluctuation of the quality of some parameters. 

Second, we must quantify the target production over certain farming period (e.g: kg/month, mt/year). By knowing our targeted production, we may calculate the maximum standing stock (MSS), expected oxygen consumption and waste production from our system. We also will be able to calculate the water flow rate, solid and biological  filtrations systems. So, give our system a targeted production, say 12 mt/year.


Third, make a simulation standing stock for our 12 mt/year farm. Are we going to stock our juvenile in batches or all at one go? Say we are going to produce in 12 batches (1 batch/month) at 0.8kg/fish at 90% average survival rate. The survival rates for each month will be different. Normally, the fish survival will be higher when the reach bigger size. The farming period will be 8 month per batch. Therefor, we are going to stock  1280 fish juvenile/batch for each month.   If we are going to use fry of 50g each, in the first month we will have 51 kg of biomass in our system. Next month, with 83% of survival rate and average weight of 70, the same stock will grow becoming 158g each and the total biomass will become 168 kg. At the same time, the 2nd batch will weight 51 kg in biomass making total biomass in the 2nd month will be 219kg. The calculation goes on and on until we reach full 12 batches in the twelve month with biomass of 5034kg. Remember, we are going to sell our yield at the end of 8th month of each batches and restocking new fry in the next month. So, our calculation will results like this:

Standing Stock for 12 mt grouper farm with the Maximum Standing Stock (MSS). Table: Mahmud Ismail.

In order to know the highest standing stock of our system, we simulate the calculation until all batches in full operation. The highest standing stock for our system is 7264 kg which going to take place in the 16th month of operation. This value is called as Maximum Standing Stock (MSS) which indicates the highest load in our production in term of biomass of the fishes, maximum intake of feed and consequently the maximum waste formation. As can be seen, our MSS value is  around 61% of the targeted annual production.


Normally, we feed our grouper fishes around 1.2% to 1.5% of thier body weight per day (for calculation purpose, we use 1.3%). So, during the month 16, our Maximum Feed Consumption (MFC) will be: 7264 x 1.3% = 94.4 kg/day. However, in actual situation, the feeding rates varies according to the size of the fishes, at early stage (smaller size) the feeding rate normally higher then the feeding rate when the fishes are bigger in sizes.  


We shall continue later with calculation for oxygen consumption, carbon dioxide, biological oxygen demand (BOD), suspended solid and ammonia productions from this basic knowledge of MSS and MFC. Later, we shall also calculate the water flow requirement as well as the solid filtration system and the biological filter of our farm.  

Genetically Improved Farmed Groupers (GIFG)

There always some inspiration when I look at salmon industry. The industry growing in a very focus way to improve its productivity, efficiency and reducing the effect of potential problems. a lot efforts has been done to perfect the industry in various aspects. One of it is the genetic improvement of the farmed salmon strains. Recent report by FishUpdate  dated January 31, 2011 mentioned on the progress of study in Infectious Pancreatic Necrosis (IPN) virus resistance gene in salmon. IPN virus is  a major killer for commercial salmon farming especially for young fishes all over the world.

The researchers from University of Edinburgh, Institute of Aquaculture at University of Stirling and geneticist from Landcatch Natural Selection Limited (LNS) in United Kingdom manage to find this gene. In 2008, they published the evidence of an IPN resistance gene which is beneficial to prevent death of salmon from IPN. For the first time in aquaculture, LNS used marker assisted selection, an advance form of selective breeding, to improve resistance to IPN in their commercial strains. Further study now going on to find the precise location of the gene in the salmon genome and to identify additional genetic markers closer to the resistance gene. These Single Nucleotide Polymorphism (SNP) markers used to select the IPN most resistant fish for breeding. Their works surely shown a way for researchers in grouper industry to apply such leading-edge genetic and genomic technology in grouper's genetic selective breeding to help farmers to get a better strain for fast growing, disease resistant and highly demanded grouper fishes.



Hybrid between female tiger grouper and
male giant grouper.

 So far, not much result of groupers genetic research available in this country or even from this region. However, I must pay my respect for the best work done by some researchers in cross breeding of Giant Grouper (E. lanceolatus ) and Tiger Grouper (E. fuscoguttatus). Although this finding was not based on the work at gene level, I would say it is seriously a good achievement and should deserve all the credits. The output of this hybridisation technique currently in high demand in the market, getting very good price and acceptance at the consumers level.

Tilapia nilotica: Original and modified to suit the
colour's preference of the oriental markets.
Photo: Mahmud Ismail 

Last few years, the tilapia farming got a boost from the introduction of Genetically Improved Farmed Tilapia (GIFT) which brought good results in term of growth rate and flesh recovery which helps thousands if not millions of farmers around the world. I love to see such development in grouper farming. Since we do have good example from other farmed species, the chances of duplicating such process to the grouper species seem to be very natural way of getting the fastest results, before more serious works take place. Off course the situation of tilapia culture seem to be more easier than groupers culture due to single species (Oreochromis niloticus) needed to look into in the case of GIFT.

Since early of this millennium, some researchers already emphasize the need for further research on genetic improvement for the grouper species. I flip through some papers presented in one workshop on grouper aquaculture back in 2002 ( you can download it free for your own leisure reading from Proceeding of Grouper Workshop) and found suggestion from one presenter that emphasize the need for genetic improvement of the cultured grouper species. In this region, I saw some works on genetic improvement for grouper have been carried out in neighboring country but actual result from the study still not yet being published.

Should we become one of the scientist studying the genetic improvement of the grouper species, what could be our priority to look into? Perhaps the fast growing gene in Mouse Grouper, low salinity tolerant gene in most of grouper species, VNN virus resistant gene or something like new hybrid between Giant Grouper with Coral Trout? As for me, most probably I will go for fast growing gene for Mouse Grouper and Coral Trout. Perhaps, I will produce another version of GIFT for these kind of groupers. Can we call it GIFG?

Softshell Crab and Grouper Investments.

Yesterday and today news from local business news paper Business Times attract so much of my attention. The news not directly involved with grouper species, but since it involve with a move by a public listed company which seriously considering to invest in aquaculture industry, a kind of news that always being waited for by those who are involved in this field in Malaysia.

The news today is about the plan of Texchem Food Sdn Bhd, a wholly-owned subsidiary of Texchem Resources Bhd (TRB), whom has started laboratory-scale trials and experiments in the hatchery process of the mud crab. Texchem Food, which has been engaged in the seafood business for over three decades, is positioning itself as the world's largest processor and exporter of soft-shell crabs with access to a consistent supply of crabs in the region over over 100 tonnes per month. Yesterday, the company have signed a memorandum of agreement with Universiti Sains Malaysia (USM) to jointly study and do pilot-scale trials at the university's Centre for Marine and Coastal Studies (CEMACS) in Muka Head, Penang.

I like what being mentioned by Chairman and Chief Executive Officer of TRB, Tan Sri Fumihiko Konishi, who is mindful of the sustainability of natural resources and always ahead of the times with business trends, has not missed a beat in anticipating how an increasing market demand of soft-shell crabs will eventually stress the crab fishery. Everyone in seafood industry surely will agree Tan Sri Fumihiko on that remarkable note. The grouper fisheries have seen such pressure on some of the grouper species in Malaysia and all over the world and As I did mentioned in my earlier postings, I strongly believe that aquaculture could be the answer of this issue, should it being managed in a sustainable manner. 

Ability to produce fry from cultured animals should be the priority  for all of us in aquaculture industry. Dependency on wild broodstock have limitation and still giving some pressure to the natural stocks although almost unavoidable at early stage  of aquaculture industry development for certain species. For that matter, I take my hat off for TRB effort in developing a local in-house hatchery expertise for soft-shell crabs which aimed at acquiring the capability to produce crablets for further development.

Although I have seen softshell crab farming and crablet hatching since end of 20th century, the growth of that particular activity does not grow fast enough in this country. However, I must say there are already players who are producing this product in a relatively  serious mode but not yet at an industrial level. I hope the new effort by this TRB will boost the softshell crab farming to a higher level in Malaysia.

Another point in this two days news is the cooperation with the local research intitution, in this case USM. The initiation by both parties surely can ensure the potentials of crab farming and softshell crab production go beyond normal crab farming and fattening project. So much knowledge should be acquired and so much technical know-how must be perfected to ensure crab farming and softshell crab production achieve a sustainable level and eco-friendly to nature. Hopefully, other species such as groupers will get the same kind of attention from other PLCs and research institutes to push the aquaculture and fisheries industry into a new frontier. For those who are interested in softshell crab production, I recommend this book, Soft-shelled crab production: Options and opportunities for your reading.

Orange Spotted Grouper, Kerapu Pinang, Epinephelus coioides

Orange Spotted Grouper. Photo Credit: Randall J.E.

Locally, this species were called with many names as in case of other grouper fishes. Kerapu Pinang, Kerapu Balong, Kerapu Rintek and other names.  When I start to get involved with this species back in 1997, the farmers call this fish as Kerapu Pakpanang, probably because the fry of this species were imported from an area of the same name in the neighbouring country. Back then, Orange Spotted Grouper (OSG) was among the important species of groupers that were cultured in this country before the currently cultured species start to gain their popularity among the farmers. However, this species are still being cultured in this country with intended local and export market.

OSG always associated with the coral reef ecology but sometimes also can be found in the brackish water from the depth of 1 meter to 100 meters. They were also found in the brackish estuaries ecosystem especially for the juveniles. This species can be found in the seas of  37°N to 34°S and 28°E  to 180°E which include Indian Ocean, Red Sea, Andaman Sea, Malacca Straits, South China Sea, China Sea and Western Pacific Ocean. There were reports of catches of this fish in the Mediterranean Sea.

Mangrove area at the estuary where OSG can also be found. Photo: Mahmud Ismail

This species fed on fishes, squids and crustaceans. In our waters, the juveniles were found weeks after rainy season were over or weeks after heavy downpour suggesting that the spawning taken place immediately after rainy seasons is over. Some scientists predict that there are spawning aggregasion behaviour for mating time and their eggs floating below the surface level. They were pelagic during larval and juvenile stages. Some other suggest eggs, larval and juveniles were pelagic due to existing of all levels pelagically.


Price of OSG quite stable for the last 3 years. Source: Fish Marketing Organisation HK.



 In the last 3 years, this species enjoyed relatively stable price between HK$105/Catty to HK$131/Catty and the last one week from the date of this posting, this fish were priced between HK$130/ Catty to HK$140/Catty. The price of OSG was much below then our other popular species such as GG, TG, MG and Coral Trout, but always higher than GGG. In the local live fish markets, the ex-farm price were  species still remain good especially for live seafood markets. For me, should the demand for OSG getting bigger and the price is better, or we able to reduce the production costs (with better FCR, genetically improved fry),  this species is the choice for our local aquaculture industry. The researchers from this region has shown their innovation when they manage to mass produce the hybrid of TG and GG in the last few years. Why not do something on this species too? Perhaps an hybrid between OSG with GG?

Giant Grouper, Kerapu Kertang, Epinephelus lanceolatus

GG as they popularly known among the researcher and farmers. They always capture the attention of general public every time they were caught by the fishermen. Records shown they can grow to hundreds of kilogram and achieve an old age of 60 years old.


Giant Grouper caught in Perak. Source: Utusan Malaysia



In my previous post, Common Grouper Fishes Of Malaysia, I did mentioned how special and popular this fish to the local of Asian populations. Believed and beloved due to the potential of superpower that they might bring, the fish naturally gain popularity to all of us, the grouper interested people, be the farmers, fishermen, fish culturists, hatchery operators, researchers and the seafood lovers.  It have been said that GG is  very rich in protein and vitamins, high in calcium, which are beneficial for bone development, able to curb blood clot, having anti-cancerous properties and also good for brain development. As in many deep water fishes, the GG skin is high in collagen, the element that known to prevent ageing process especially to the skin if being taken regularly. Even the GG scales also reported to be very nutritious and having remedial effects. Every part of GG has its own special usage, from scales, bones, fins, lips, tails, skin, liver, intestine, gill, tongue, bladder, roe or even its sperm duct . No wonder it was so much being looked after, the buyers will not waste any part of the fish and will not waste their money on this fish. 

Due to its high demand in the markets and their maturity size, this species is now considered under the International Union for Conservation of Nature's (IUCN) Red List. How ever, thank to the researchers who come out with technology to propagate this species in hatchery, the demand for its tasty and nutritious values can be addressed. As in my many postings, I really feels that this is the way to overcome the problem of over fishing for all species of marine organisms be it as small as sea-horses to the giant whales. Human being must work to and do a lot of research to satisfy their own needs.




Distribution of GG. Source: fishbase.com

 

Giant grouper normally found in the reef associated waters and said to be the biggest bony fish in that ecology. They are common in the shallow water and used to be found in even brackish water. They feeds on crustacean, fishes and squids. Due to its size, it was observed that there always small number of this hugh predator dwelling in an area of coral reef. The big fish always found in their "home" cave from as shallow water of 4 meters up to 100 meters deep.

As being shown in the map above, this species is most widely and largest distributed among the groupers species but rarely found in all locations. It inhibit from  throughout the Indian Ocean, Pacific Ocean, Andaman Sea, Malacca Straits, South China Sea, covering a region from the Red Sea to South Africa and eastward to the Pacific islands up to Micronesian islands. In western Pacific from southern Japan southwards to Australia.  It covers tropical and temperates waters ranging from 29°N to 39°S, 24°E to 122°W.



Clean water in the coral area makes the best place for Giant Grouper.
Photo: Sim See Hong

 

According to a scientific report, based on their observation of  250g GG fishes that being cultured in the cages, this fish achieved its maturity in the fourth year. With an average growth rate of 19.51 to 22.76 gm/day and length increase at 0.035 to 0.58 cm/day, at the end of fourth year, its sizes were around 28.27 to 28.31 kg. Some reports says that GG can grow up to 400 kg.

The growth rate of 19.51 to 22.76 gm/day is considered very good growth rate indeed for aquaculture species. If our fish farmers stock their fry of 250 gm each, theoretically they only need an average of 64 days to get their GG to achieve market size 1.5 kg / fish! Even if we give another 64 days for its culture periods, this species IS still the 5 stars fish for all of us!  The same report confirmed that GG can achieve 1 kg weight within 4 months.  No wonder in Malaysia even GG fry price is around RM30 each. Hey, we not yet discuss the price of GG!

 

4 years old for maturity is considered not that too long for us to work with this species. Further, we know their weight during that time is around 28 kg and above. So, keeping our own broodstocks from our own fry, do the genetic selection process based on their growth rate could be our option for this species.

According to an assessment done in 2006, the small size GG price was around US$169/kg in HongKong. The small size GG (1.5 - 1.8kg/fish) were more preferred by the outlets in that market. HongKong was reported as the main importer for this species but some fishes were trans-shipped to mainland China. The other markets including South East Asian countries. I believe mainland China will become the major importer of this species in the very near future, and it will only be limited by the ability to supply the market size GG to that market by producing countries.

Coral Trout, Kerapu Bara, Plectropomus leopardus .


 


Coral Trout, P. leopardus

 

This species already in the Malaysian aquaculture and fisheries industry for quite sometimes, they have been sought after by the fishermen and aqriculturist as well as the seafood restauran operators.  Lately, they are commonly cultured especially in Sabah, Pulau Pinang, Perak, Selangor and Johor. The landing from the wild catches always sporadic all over nation.






Transporting Live Coral Trout in Semporna, Sabah.



This fish getting very good price in local and export markets. In some places in Malaysia, this fish will be caught alive. The off-sizes fishes will be kept  in the cages and be fed with fresh fish until they grow to the market size. Although this method of farming has been debated due to utilisation of natural resources and not that efficient in reducing the pressure on natural stocks plus the usage of food fish to fed the fish, I still consider this method as a value addition process to increase the value of the off-sizes Coral Trout that have been caught by the fishemen.

The commercial farming of this species always using the imported fry from other fry producing nations. There is no report of fry production of this species in Malaysia so far though there could be some unreported productions from the commercial hatcheries.




Distribution of Coral Trout. Source: fishbase.org

 

In the wild, this species always associated with coral areas at the depth of 3m to 100m. It usually can be found from 35°N to 30°S and 99°E to 178°W, from Eastern Indian Ocean to Western Pacific Ocean. The biggest recorded weight was 23.6 kg and with body length 1.2 meters though normally found was around 0.5 kg to 3.5 kg and with body length between 20 cm to 35cm. The longest repoted age of this fish was 26 years. The fish sexually mature at the length of 21-60cm. The adult fish feed on fishes and squids. They are protogynous hermaphrodite (initially as functional females, then turn into functional males at certain age). They normally spawn during new moon phase and having spawning aggregations behaviour during mating process in the reef area.  Their fertilize eggs will float just below the surface of the sea water until hatched. The juveniles of Coral Trout feed on small fishes and crustaceans and normally found in the demersal of shallow coral areas.

In term of price, I saw this species have enjoyed very high price for the last few years with last year highest price of HK$700/Catty and lowest HK$300 and average price of HK$545/Catty making it a very good high value species in HongKong market. The colour of this species also suit to  our Asian taste for happy colours of our foods. Red and golden spotted always associated with good luck and prosperity to us, the unique Asian people.

With good demand and good price, it really supprise to see that this species is not among the popular marine fishes that be able to be reproduced in this country. Perhaps, we do really must strategize our priorities of the targetted species that we must pay attention to. I read an article published in an aquaculture journal back in 2001 that some countries already started producing the fry of this fish way back in 1985.  We hope to see some changes this year and hope there will be some report on the production of this species by Malaysian hatcheries.