An Amazonian fish species with the potential to become a Brazilian commodity on the world’s markets
February 23, 2022
By André Julião | Agência FAPESP – A fish for which there is market demand and that produces many offspring, grows fast, has a mainly vegetarian diet and thrives in water with relatively little oxygen is a dream for any fish farmer.
The tambaqui (Colossoma macropomum), also known as blackfin pacu or cachama, fits this description. Production has reached 100,000 metric tons per year in Brazil, behind only that of the tilapia (500,000 mt), without heavy investment in innovation and genetic improvement.
The difference is that the tilapia, originally an African genus, underwent a major selective breeding program in Asia, starting in the 1980s, and the result was GIFT (genetically improved farmed tilapia), currently produced in 14 countries, including Brazil, which also has an entire industry dedicated to research and development of products for this market segment.
The tambaqui is a native of the rivers of Amazonia, and researchers believe its natural characteristics give it the potential to conquer not just the domestic but also the global market, becoming a veritable Brazilian commodity. For that to happen, however, investment in innovation is needed, argue the authors of an article published in Reviews in Aquaculture.
“An Amazonian fish that has a 75% vegetarian diet and is very easy to manage has huge potential as a sustainable product at a time when aquaculture is under attack because of the environmental impact of salmon farming, for example,” said Alexandre Hilsdorf, first author of the article, adding that salmon was the first fish to become an international commodity. Hilsdorf is a professor at the University of Mogi das Cruzes (UMC) in the state of São Paulo (Brazil) and a researcher affiliated with its Integrated Biotechnology Center.
The article reviews the scientific literature on tambaqui farming, which began in the 1930s, and covers production systems, genetics, nutrition, diseases and processing methods, among other aspects.
FAPESP has supported the science produced on the tambaqui in recent years, funding research by some of the authors of the article, including Hilsdorf, who acted as principal investigator for the project “Integrated studies of quantitative genetics and genomics for economically important traits in the tambaqui (Colossoma macropomum)”.
Hilsdorf was one of the scientists who sequenced and analyzed the genome of the species, as detailed in an article published in September 2021. He also led a study that described tambaqui specimens without intermuscular bones commonly referred to as Y bones, requiring removal when filleting many species. Another study identified genes that could be associated with the absence of Y bones in the tambaqui.
In an earlier study, his group estimated genetic parameters for several economically significant traits of the tambaqui, such as those that determine the area of the loin, one of the cuts preferred by consumers. In conjunction, the studies establish scientific parameters for the development of varieties genetically improved for the market.
“Pork loin, for example, is the result of genetic improvement. The pig breeds we have in Brazil were selected to have less fat and more loin,” Hilsdorf said. “Breeding can ensure that tambaqui cuts such as loin and rib result in even better products in future.”
Manaus, the capital of Amazonas state, consumes the largest amount of tambaqui. In the 1970s, the city relied almost entirely on local river fishermen to meet demand, whereas the main suppliers now are fish farmers in neighboring states such as Acre, Rondônia, and Roraima.
In the wild, a tambaqui can easily weight 10 kg, but restaurants in Manaus prefer to serve farmed juveniles weighing 2-3 kg. “Restaurateurs prefer this size. They always want to buy a standardized product,” Hilsdorf said.
Paradoxically, the traits that make farming the tambaqui an attractive business proposition also tend to discourage investment in breeding. Broodstock (mature individuals used for reproduction) are purchased from other fish farmers or captured in the wild. Production of spawn and fry in large numbers, as well as rapid growth – a juvenile can reach 2 kg in a year – and hypoxia tolerance mean farmers have little incentive to spend money on improvement.
“Not investing because the species already performs well is a mistake,” Hilsdorf said. “If it reaches 2 kg in a year, with breeding it could do so in nine months, for example. Producers who do invest in this will be able to sell fry or broodstock to neighbors and get ahead of the curve. It means investing for the long haul and taking a certain amount of risk, but history shows the rewards are worthwhile.”
For this species, ambient temperatures have to be between 25 °C and 34 °C, meaning that in Brazil it can be viably farmed only in the North region. If varieties resistant to lower temperatures were developed, they could be produced in many other parts of the country, for example.
Instead, the industry has preferred hybrids with species that live further south of the equator, such as tambacu, a cross between tambaqui and pacu (Piaractus mesopotamicus), or tambatinga, a cross with pirapitinga (Piaractus brachypomus).
“We have sufficient genetic resources to develop varieties with different profiles in terms of resistance to cold, low oxygen or disease, without bones, and with higher production of offspring and meat, among others,” Hilsdorf said. “We don’t need to breed hybrids, which threaten the integrity of wild genetic resources when they escape from fish farms. Producers should go further, seeking genetically superior products for the establishment of an economically and ecologically sustainable pisciculture industry. That’s what the global market currently requires.”
The article “The farming and husbandry of Colossoma macropomum: from Amazonian waters to sustainable production” is at: onlinelibrary.wiley.com/doi/abs/10.1111/raq.12638.
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