Hi everyone, we are the team at Can Tho University (Viet Nam) working on the project of developing Operational Welfare Indicators (OWIs) for cultured snakehead fish (Channa striata) in Viet Nam. It has been a while since our last post about the project. The project, as of the time of this post, is in the finalisation stage. Since the previous post, more farms were visited, and more farmers and farm managers were asked to complete the questionnaires. We also visited markets and supermarkets in Can Tho city to assess OWIs for snakehead fish in the supply chain (retailers). In this post, we will focus on assessing OWIs at retailers and the behaviour of the animals when fed.
Regarding feeding time on the farms, these snakeheads are quite the characters. Farmers have observed that well-cared-for fish are eager eaters, gathering quickly and devouring their food without much fuss or aggression. They even learn to associate sounds, like tapping or feeding machine noises, with mealtime. This active feeding and calm demeanour after meals, where they leisurely swim or hide in the shade, are all signs of excellent welfare. Farmers are careful not to overfeed, usually giving about 90% of what the fish could eat, a practice based on experience to prevent health problems. The fish are typically fed commercial pellets twice daily, with a good crude protein and lipid content. A video of snakehead fish during the feeding time is shown above.
In Viet Nam, consumers prefer fresh live fish, hence the fish sold at retailers are live fish. Therefore, assessing the snakehead fish's supply chain from farm to market is essential. During this project, we could not find any transport to do the assessment; therefore, only retailers were assessed for this project.
Before we move on to the fish at retailers, we briefly describe two terms: traditional retailers or traditional markets, and supermarkets. Like other supermarkets worldwide, it operates daily, non-stop, daily to night. It’s a closed and temperature-controlled environment, and the supermarket is the sole retailer. On the other hand, many retailers do trading at traditional markets, each with its methods of selling and managing its products. Moreover, the traditional markets are not a closed and temperature-controlled environment; they might have a roof over their head. Operating times of traditional markets might vary between retailers. Number of animals, at once, the supermarket imported more fish than each retailer at the market. This could be due to the supermarket being a closed environment, so they can keep the animals overnight at the facilities, whereas traditional retailers tend to try to sell all the products during the day.
Because the nature of the retailer does not keep the fish in the water for too long (within a day), the fish are usually presented out of water, and the animals are not fed during the period of keeping; therefore, for the OWIs of snakehead fish at retailers, we only focused on the physical health and behaviour of the fish. The study examined physical health and behaviour in traditional markets and big supermarkets in Can Tho City. Interestingly, fish from traditional markets generally showed good to perfect physical condition. They might have had minor scale loss or body damage, but their eyes and fins were usually spotless. Even after being out of water for extended periods (which snakeheads can surprisingly handle for over 8 hours thanks to their air-breathing abilities), these fish were lively, reacting strongly to movement, and simply gasping for air rather than being lethargic. Their gills, however, sometimes looked a bit dark or pale, likely due to that time out of water.
On the other hand, the snakehead fish found in supermarkets, typically kept in glass tanks, told a different story. These fish often showed more physical issues like lesions and ulcers. They were also observed to be less active, sluggish, and didn't gasp for air as much, even when handled. The study suggests this might be due to their time in these live-holding systems and how they are maintained, including high stocking densities and mixing new fish with older ones. Sometimes, white, mould-like matter was even seen on their bodies, possibly related to cooler supermarket temperatures.
That is a brief update on the study at Can Tho University. We will make a formal press release when the project is finalised. If you have any questions or discussions about this project, you can contact us by email at tmphu@ctu.edu.vn.