How AI is helping to solve key fish health issuessafs

A new artificial intelligence (AI) tool that can help provide a detailed evaluation of Atlantic salmon skin is currently being developed by researchers at Nofima.
Artificial intelligence is a comprehensive branch of computer science where machines are trained to perform tasks that usually require human intelligence. The machines know nothing from the start, but they can be trained to recognise highly complex patterns.

At Nofima we have developed an AI package for the evaluation of salmon skin - the health of which is vital to the health of the whole fish - using the commercial Aiforia platform. In order to train the algorithm, we used several different sample sets, from 100 g smolt to 5 kg salmon that are ready for slaughter. This resulted in a unique AI-model that is able to measure salmon skin structures.
Many more samples
Skin is a type of tissue that is eminently suitable for machine learning as it consists of several different layers and cells in varying shapes, and sizes. The outermost skin layer, the epidermis is important for the health of the fish, as it seals the skin in order to prevent it from leaking, and is also involved in fighting off bacteria and viruses. This part of the skin also produces mucous, which acts as a protective layer around the fish. The subcutaneous tissue consists of scales and connective tissue which are important for the swimming movements and flexibility of the fish. All of these components were included in the AI-model, and during the course of 2020 nearly 1,000 images were analysed using machine learning.
Using the skin analysis AI software, we tested skin from salmon produced at a commercial location in northern Norway. With the help of the AI-model, we analysed many more samples than would normally have been possible when using manual methods, providing a far larger data set, and thus more reliable sample responses.
Mortality and skin quality
The AI results from commercial fish from the northern part of Norway, taught us that the dynamics of the skin’s epidermis and subcutaneous tissue are different. The dermis grows steadily as the fish develop. This means that the skin becomes thicker as the fish grows, something which in turn is important for its mechanical functions. The outer layer of skin, epidermis, is not connected to the growth of the fish. On the other hand, the structure of this layer changes in line with the external environment, for example if the temperature changes.

We were also able to establish further connections between mortality and skin quality. The mortality rate was highest during the first few weeks following transfer to sea, and it increased after transport and towards the end of the production cycle, when the fish were more often exposed to mechanical delousing. The mortality rate coincided with various structural impairments in the skin of the salmon. We know from previous studies that transfer to the sea weakens the skin's immune system (Karlsen et al., 2018), and even superficial wounds (loss of mucous and scales) in healthy fish increase the risk of infection.

Future use of the AI model
Based on our analyses and previous studies on wound healing, it would appear that the skin is able to withstand some injuries and heal quickly. But we still know very little about the effects of repeated mechanical treatments on the skin's ability to repair itself, or what percentage of scale loss causes problems with regulating the salt balance in the fish. More targeted scientific work is required in order to find out the thresholds for scale loss and skin damage for fish in the sea, and not least, how various forms of mechanical delousing and repeated treatments affect fish skin quality over time.

Having now used the software for several projects, we are starting to form an idea about what the skin of a healthy fish should be like. In order to obtain a better overview on general fish health, we have gone one step further and developed similar AI algorithms for the liver and gills. Our long-term goal is to create large, reproducible datasets for many organs, to better understand the relationships between the health of the organs, the production data and the way in which the fish have been treated. Such analyses will enable us to evaluate fish health in a more holistic and more intelligent way in the future.
As kelp aquaculture is a relatively new industry in Norway, and in many parts of Europe, there are many challenges to overcome before production can increase and become commercially viable. Active cultivation sites in Norway are scarce and concentrated towards the southern and mid-coastal regions; however, kelp farming also shows great potential in northern Norway. Therefore, researchers at Nofima are currently focusing on sustainable value creation from kelp production in northern Norway.

The world’s largest aquaculture crop
Despite seaweed being a relatively new aquaculture species in Europe it is – in terms of harvested volumes – the largest aquaculture sector in the world. There are three types of seaweed: brown, red and green. Although there are a vast range of species (with approximately 10,500 described) the production of seaweed is concentrated on nine genera, including well-known species such as Japanese kelp, nori and wakame.

Seaweed represent more than half of the total worldwide production of marine aquaculture by volume and 99 percent of this production is concentrated in Asian countries. Recently, seaweed farming has expanded to European countries, with Saccharina latissima (sukker tare in Norwegian, or sugar kelp in English) being the most important and commonly cultivated commercial species. Kelp species are excellent candidates for aquaculture as they are among the fastest-growing organisms on this planet (growing up to several centimeters per day) and are capable of reaching more than 2m in length during a single growth season. They are attached to growing ropes by holdfasts, which only have an anchoring function and – unlike the roots of terrestrial plants – these are not requited for the absorption of nutrients. From the holdfast elongate stem-like structures called stipes, and then blades, develop.

https://zenodo.org/communities/sutejomusaman/
https://zenodo.org/communities/terpolosonmas/
https://zenodo.org/communities/pupurulukans/
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https://www.guest-articles.com/education/how-ai-is-helping-to-solve-key-fish-health-issues-19-02-2021
https://gumroad.com/astreignsas
https://muckrack.com/puls-sars/bio
https://astreignsas.medium.com/how-ai-is-helping-to-solve-key-fish-health-issues-4953e043ec4b
https://500px.com/photo/1028705414/hi-mom-1-by-pura-puras/
https://note.com/samamh/n/na8d40700f0f4

Applications and benefits of seaweed
Most farmed seaweed biomass is consumed as food, as they are rich in minerals and vitamins, with some species also containing high amounts of proteins and fatty acids. Extracts from seaweed can be used in a wide range of product applications – such as animal feed, toothpaste, cosmetics and medicines – that contain hydrocolloids for gelling or thickening purpose. And more promising and innovative applications are coming, including textile and plastic alternatives for packaging, and coatings for food containers and drinking straws. However, there are concerns about the health effect of high iodine intake from seaweed. The variation of iodine concentration is large between and within species. Brown seaweeds contain a high level of iodine while green and red seaweeds, including the popular sushi seaweed nori, are relatively low in iodine. Moreover, the iodine content can be reduced through processes including drying, boiling and frying.

Seaweed also provides several key ecosystem services and could help to solve several of today’s most pressing environmental and social sustainability challenges. In integrated multi-trophic aquaculture (IMTA) systems, kelp can be integrated with fed species, such as salmon, and non-fed species, such as oysters, mussels, scallops to reduce the nutrient loads, improve the water quality, increase the biodiversity, at the same time enhancing the overall productivity of the system.

As a primary producer, kelp absorbs CO2 and converts carbon into biomass. Large-scale cultivation of kelp provides a promising means to reverse ocean acidification and to help reduce the impact of the current climate crisis. This also closely aligns with existing efforts to restore ocean health and create a sustainable ocean economy.

Different production systems
To cultivate kelp efficiently, understanding the physical and biological factors that affect survival and growth – as well as developing appropriate production strategies – are among the keys to success. The main environmental variables for the growth of kelp are the availability of nutrients, light, temperature and currents. Kelp can be grown in fjords, as well as the near-shore and offshore environments. In addition, it can be integrated into existing mariculture installations, or windfarms.
Northern Norway is perfectly suited to kelp farming
Kelp farming faces a number of challenges but also advantages in areas that are not currently used to produce seaweed. Active cultivation sites in Norway are scarce, even though kelp farming shows great potential in northern Norway. Photosynthesis is key in the cultivation of kelp, and in the north there is sunlight around the clock during the summer season, meaning that growth rates are amazing in this period, with huge potential to develop a kelp industry.

Sugar kelps are cold-water species and seawater temperature below 10°C are suggested to be the optimal temperature for their growth and the key factor foe delayed outbreak of epiphytic (fouling) organisms. This is one of the main challenges to viable seaweed cultivation, as once the plants become overgrown with fouling organisms they rapidly lose their value. The seawater temperature in one of Nofima’s experimental sites in the north never exceeded 10 °C during the growth period (February to August), which is a perfect location for kelp cultivation.

Kelp cultivation produces large volumes of biomass that must be harvested and processed during a very short and intensive period (dictated by the onset of biofouling). The growth season in southern Norway ends in May, when water temperatures increase, and the epiphytic organisms start to occur on cultivated kelp, making them unsuitable for human consumption.

Our preliminary results showed that the outbreak of epiphytic organisms was considerably later in northern Norway, which allowed for a prolonged growing season and later harvesting in July/August. Despite the lower temperatures the biomass yield in the north is comparable to that experienced in the southern and mid-coastal regions of Norway. Results from Nofima trials revealed large variations in the kelp growth and quality, even within the northern region.

A site with lower temperature and normal salinity experienced better kelp growth than another site close by, regardless of the origin of the mother plants. This shows that in addition to geographic location, the local environmental conditions will be key to locating seaweed farms in the north of Norway.