Resilient Fish, Sustainable Future: Adisseo’s role in combating heat stress in aquaculture
An exclusive interview with Adisseo’s expert team to discover how they are helping fish farmers respond to key challenges linked to climate change.
Over the past few years, the effects of climate change have increasingly impacted the aquaculture sector, with rising water temperatures risking fish health, not only causing heat stress but also provoking higher levels of pathogens.
WeAreAquaculture spoke with three key members of Adisseo’s aquaculture team, all experienced fish veterinarians and aquaculture nutrition experts, to learn how Adisseo is helping fish farmers successfully navigate these key challenges to ensure optimal fish health and growth, regardless of location or production method.
“We believe the effect of climate change on aquaculture, particularly the increase in water temperature, is a crucial challenge. It impacts aquaculture from the south to the north, making fish farming more complex and causing significant difficulties for fish farmers,” explains Robin Carpentier, fish veterinarian and Adisseo’s European Regional Sales Manager for Aquaculture.
“When I was interviewing for my current position, someone asked me what I thought was the biggest health issue in aquaculture. The first thing that came to mind wasn’t a pathogen but rather the impact of climate change,” he said.
“It’s recently been reported how sea temperatures are rising in Norway, but the same is happening in parts of the Mediterranean, particularly in the east. In species like seabass and seabream, we see rising water temperatures leading to stress – oxygen stress, temperature stress – and the development of certain pathogens. The same applies to freshwater aquaculture in Europe. In several countries, the water temperatures have reached more than 25°C which is extremely challenging.”
The results of this can be catastrophic for fish farmers, Robin points out. “This leads to an explosion of pathogens, stressed fish that are more susceptible to disease, production losses, and high mortality rates. It’s not just about warmer water; there’s also less water due to reduced rainfall.”
“This feels like the driving force behind many current issues in fish farming, not just in the Mediterranean but across Central and Northern Europe as well. As a veterinarian, this is something that deeply concerns me, and I work to help fish farmers navigate this new reality.”
Waldo Nuez Ortín, Adisseo’s Head of Aqua Global technical support, reflects that only a few years ago, the risk of thermal stress was often dismissed, but he and the Adisseo team already had the issue on their radars. “Now it has become an urgent topic,” he notes.
“In the past, cold stress in Mediterranean species like seabream was a well-known issue. Many different solutions have been explored – farm management, genetics, nutritional additives, vaccinations – so that aspect is well controlled. But heat stress is a key challenge to be adressed,” explains Maria Mercè Isern i Subich, Global Product Manager Health for Aquaculture.
“Trout farmers already recognize that summer conditions in certain regions are becoming increasingly tougher. It’s not just heat stress itself affecting fish, but also related factors like pathogens, nutrition, and water quality. The impact is broad, affecting multiple aspects of aquaculture management,” she adds.
Combating heat stress
However, it is possible to combat heat stress through adjustments to aquaculture feed, Waldo explains.
“One of the strategies is to improve the antioxidant capacity, by supplementing extra vitamins and minerals that support the activity of anti-oxidant enzymes. Phytobiotic based additives provide support to the anti-oxidant system by enhancing the expression of anti-oxidant enzymes.”
Waldo and his team combine in-vitro models to test the anti-oxidant capacity of different ingredients with in-vivo models of heat stress to test the biological impact on different fish species. “This platform enables us to benchmark different solutions and optimise formulation,” he explains.
However, beyond the direct physiological impact of heat stress on the fish, the warming waters themselves bring an array of environmental challenges, specifically in enabling pathogens to survive even during the winter months.
“The warmer waters bring an adaptation of the existing challenges," Maria points out. “In the past, there were periods in the year where some parasites or pathogens disappeared, but now with milder winters, the pressure is higher because they are present all year round.” This means that an important part of Adisseo’s role is to provide support on disease prevention and boosting fish resistance to infection.
‘On several occasions we helped to reduce the impact of parasitic disease in sea bream in field conditions using a holistic approach of our feed additives and other preventive tools.’
Different species, locations and farming methods are other important factors to be taken into account, Robin notes. “For example, a trout farm in western France will be impacted differently than a salmon farm in Norway, or a sea bass farm in the Mediterranean.”
Cold water aquaculture may be able to learn from decades of experience in (sub)tropical climates. Climate change is further stretching what we already experience in aquaculture in tropical areas where temperatures (and many other parameters) fluctuate depending on the season and sometimes even on a daily basis. In these conditions, producers suffer significant mortalities during unfavourable “off-season” periods and that is exactly where our health additive strategies showed the best ROI.
"I think that’s where Adisseo can help farmers to understand what is really causing the impact. Is it purely temperature, is it temperature combined with pathogen development, or is it temperature with lower water levels and pathogens all together? We need to understand what the situation is, and to come up with a solution that can improve a myriad of different things - diet, health management, biosecurity, maybe even changing species in certain regions,” Robin adds.
Supporting skin health: “a must in production”
Another key element in ensuring robust health and welfare for farmed fish is skin health, the expert team explain. And, while heat stress and skin health are separate challenges, climate change is a factor which influences both.
“Heat stress and skin health are related, in the sense that in the past everyone was talking about pathogens, parasites, bacteria, but we increasingly learned that the parasites are not the principal actor of the story – it's the skin health itself,” says Maria.
“Salmon is a very good example of that. You may be treating the sea lice, but using mechanical treatment methods generates another problem. Parasites, handling, external treatments – all of these are stresses on the skin.”
“Supporting skin health is becoming a must in production," she states. “Of course, if you can do that through the feed in an easy way, that gives a good impact on the performance.”
How can Adisseo help with this? "With heat stress and higher water temperatures, we see a higher incidence of specific pathogens. At Adisseo, we have optimised a solution range which targets the mucus defensiveness properties and skin integrity. It has a very positive impact on helping to reduce the severity of skin bacterial infections and parasites," explains Waldo.
Adisseo’s global network of experts
Adisseo, as a global company, can draw on a wide range of expertise and experiences, and the team note that they operate as a network rather than separately by region. “If we deal with a difficult topic, we can combine each and everyone's experience to come up with the right solution for the client,” Robin explains.
An example of this philosophy is Adisseo’s Health Platform, a service where the company can connect their own team of expert consultants with customers to find a solution to any challenge, be it heat stress, skin health, or another aspect of fish health.
"Health is a very dynamic issue, it's very specific to each case. It's very important to adapt the solutions to the reality of every client. When you find something that's new for you, you can get the knowledge to give the best support. Normally the best discoveries are made in the field, so it's nice to have this big network to keep sharing and to implement new solutions,” Maria says.
“It gives us a very strong and well-positioned group of experts - from the field to the more specific lab-based researchers," she adds.
Understanding farmers’ needs with knowledge from the field
The team agrees that feedback from the field is essential to Adisseo’s approach. “It's not only the product, but also the application of the product that's very important. We bring the solutions to the field, the experience we have gathered over time and from different regions, and it's the feedback that supports the next steps to see how our products perform and how we can update them,” Maria points out.
“The true indicator that a feed additive works well is the field. So, we start in the lab to test under controlled conditions, we go to the field to validate, then we go back to the lab to further optimise, and after several cycles we end up with effective health solutions,” Waldo adds.
“The consequences of climate change show themselves very differently case by case. That's Adisseo's strong point, where we can sit down with the farmer, grab a cup of coffee, and find out what's going on and what's the best solution from the products in our range, which can be something from the Apex range or something else,” Robin says.
“Where we differentiate from the rest, is that we take the time to understand what's going on, we are there to listen,” he adds.
“We're getting ready for what's coming in the field, and we’re here to help. We’re aquaculture people, with aquaculture-specific solutions.”
Adisseo is one of the world’s leading experts in feed additives. The group relies on its 5 research centers and its production sites based in Europe, USA, China and Thailand to design, produce and market nutritional solutions for sustainable animal feed. With more than 3,000 employees, it serves around 4,200 customers in over 110 different countries through its global distribution network. In 2024 Adisseo achieved a turnover of 2.05 billion euros. Adisseo is one of the main subsidiaries of China National BlueStar, leader in the Chinese chemical industry. Adisseo is listed on the Shanghai Stock Exchange since 2015.
Produced by WEAREAQUACULTURE Brand Studio