The story of hybrid Tilapia x Jade Perch in Singapore

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A by chance hybridisation is now in generation 4 and is moving towards commercialisation

By  Joe Ng

There are variants in colour – orange, black and silver in the 4th generation of the tilapia X jade perch hybrid achieved in 2022 at Century Aquaculture, Singapore.

In land scarce Singapore, it is imperative to develop or source new species of fish that are suitable for our local industry players and where farms can easily increase production capacity just by moving further out to sea. There will be less competition for land and freshwater resources, allowing these for national development/urbanisation.

Century Aquaculture was set up in 2017 to research on types/species of tilapia suitable to acclimatise from fresh to seawater. The aim is to farm marine tilapia Oreochromis spp successfully in our local waters. We hope our efforts will help and contribute to Singapore’s food security goals for 2030. It will also give our local fish farmers a better option and move away from either farming the low value milkfish Chanos chanos in waters off Lim Chu Kang or of the high value grouper or snapper (Epinephelus spp or Lutjanus spp) in waters off Changi. Additionally, we believe that we need a fish that offers an affordable source of protein for Singaporeans.

Fish farmers in Singapore have always faced stiff price pressures from farms in neighbouring countries such as Malaysia and Indonesia, where the cost of production is considerably lower than that in Singapore. Therefore, we needed to find ways to be more competitive, at least in supplying our domestic market.

There is a good local demand for the marine tilapia in Singapore. Consumers have accepted that tilapia farmed in seawater tastes better and is unique to the Singapore market. We believe that developing marine
tilapia will not only help starve off price competition from neighbouring countries, but also offer better prospects for our coastal farms.

Developing a unique marine tilapia strain

In 2018, we embarked on a journey to search for a suitable strain of tilapia, with the assistance from two partners, trained tilapia and pangasius farming at the Asian Institute of Technology (AIT) in Bangkok, Thailand. We leased a small farm for this research and adopted the latest hatchery practices from AIT. Coincidently, when we took over the farm, we also “inherited” about 100 jade perch Scortum barcoo from the previous operator.

Some strains of tilapia that hatcheries claim can tolerate high salinity (30ppt) were tested. We stocked the fingerlings in open seawater cages off Lim Chu Kang but none survived. Most of the mortality was during the high tides, occurring every fortnight and fingerlings struggled to adapt to strong water currents. These were less than ideal water conditions with large fluctuations in salinity and temperature.

Tasty jade perch

Meanwhile, we tasted the jade perch that we had inherited. They were excellent whether steamed, grilled, baked or pan fried. Furthermore, although omnivorous, the jade perch is extraordinarily high in omega-3 fatty acids. We decided that we should produce fingerlings for the local market with assistance from the Singapore Food Agency (SFA).

After several failed attempts with different sources of tilapia, the farm decided to acclimatise the jade perch since some studies reported that it can tolerate salinities up to 30ppt. However, after numerous attempts, the conclusion was that once we reached a salinity of 18ppt, the fish could not survive. In 2019, I did the unthinkable by trying to cross breed tilapia and jade perch although biologically it would not happen since they are two completely different species of fish and the only shared similarity is that both are freshwater fish. Another assumption was that if breeding was successful, offspring would most likely be sterile.

Hybridisation of tilapia and jade perch

After a long wait of about 2 months, we produced the first batch (F1) of hybrids. However, the fingerlings (F1) were odd in terms of shape and colour. Nevertheless, we continued to get a batch of F1 fish every other month. This was the start of our hybridisation program in 2020. We spent the next two years studying and documenting this process.

Currently, we have the 4th generation of the hybrid and a few hundred female broodstock to move to the commercialisation stage (pending regulatory approval). Below are the findings that we have documented over the past 2 years.

It was apparent that the tilapia genes were dominant as the first and second generation hybrids look very much like the tilapia. There are variants in colour: orange, black and silver. The 4th generation is taking more of a hybrid shape, presumably as the gene stabilises.

Characteristics of the hybrid
This is where we noticed marked differences from the tilapia: 
a. Male to female ratio was 95% to 5% (similar to jade perch)
b. Egg production was more than 3000. This was the maximum based on current observation for a 200g female.
c. Adaptation to salinity is from 0 to 38ppt, which means that the hybrid can be farmed in both freshwater and full seawater. Fingerlings can also tolerate rapid increases in salinity from 0 – 35ppt within a week.
d. Growth of a 2-inch (5.1cm) fingerling to 450g is 5 months, based on a current open sea cage trial.
e. Flesh is firm and sweet with no muddy off flavour. This is similar to jade perch which consumers say tastes better than the red snapper.
f. Survival rates have been recorded at 98% in cement tanks.
g. Survival for swim outs is 95% indicating the ability to feed on artificial diets.
h. Survival in extreme conditions was evaluated with the following parameters – high stocking density using 2-inch (5.1cm) fingerlings at 25kg/m3 in 25ppt seawater (Table 1).

A preliminary test conducted by Republic Polytechnic, Singapore, in October 2022, showed that the hybrid is a 90% crossbreed. It is waiting for grants to run a full test on the fish.

The land based farm for saline tilapia and jade perch at Century Aquaculture uses full seawater.

Based on the above findings, we believe that the potential of this hybrid is enormous. The hybrid is not only a very hardy fish, but very economical to farm. Feeds for the tilapia will suffice to achieve good growth. With rapid urbanisation in many countries and also the pressing need to feed the growing world population, this fish might an alternative for marine farms.

More to uncover
Currently, we are conducting tests on the hybrid to determine whether it has a higher resistance against diseases that are affecting the tilapia. Theoretically, if there is a change in chromosomes (new genes from jade perch) there should be a higher resistance or immunity against common tilapia diseases. However, there is a lack of information on the jade perch since it is still not a widely farmed fish. I attribute the robustness characteristic of the hybrid to the introduction of jade perch genes. If this can be proven, the hybrid can be cross bred with popular strains of farmed tilapia to provide a “natural vaccine” for stronger resistance or immunity.

Next steps
Today, we are still in the process of selection for the broodstock to enable us to achieve a certain level of consistency in terms of shape and colour. We hope to accomplish this by the first half of 2023. There is still much to uncover on this new hybrid and whether all that we have achieved is scientifically acceptable. If so, we would like to be recognised that this achievement is probably the first of its kind in the world.

Joe Ng CW is the founder of Century Aquaculture Pte Ltd, Singapore

Note: This article was published in issue Jan/Feb 2023. In July 2023, Joe updated on the FB of Centyry Aquaculture.

Our fish is indeed a cross between Jade Perch and Tilapia, making it a completely new species and to our knowledge, it could be one of its in the WORLD!!! 

Following the publication of our article on the Hybrid Fish (Jade Perch x Tilapia), there were many enquiries and discussions amongst acedamics and industry players with most are quite skeptical over the initial tests done by Republic Poly and claimed that the test are inconclusive (though most evidence suggest that it is)

Although it is a very rare occurance but studies suggest that it is still a possiblity. We persevered and sought help to coduct a nuclear gene test on the fish and the result is positive and CONCLUSIVE

“Now we have scientific evidence to support our claim that our fish is indeed a new species, we named it Xin Sea Perch (新海鲈), as it was created, discovered and researched in Singapore (The Singapore Fish)”

Xin Sea Perch is highly versatile (can be farm in sea or fresh water) and hardy, it has high aquaculture potential, making it an extremely good food fish to farm and a potential game changer in the global aquaculture industry

Recently, we have conducted private food tasting for the fish, whether it is steam, grilled, panfried or sashimi, it passed with flying colours. Its meat texture and quality is very close to Jade perch…..firm and sweet!!!

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