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STIPINST-Stipendiatstillinger i instituttsektoren

Stipendiatstillinger til SINTEF Ocean (2017-2022)

Awarded: NOK 6.6 mill.

Eirik Svendsen: The stipend has been a part of the SalmonInsight project—a four-year research initiative financed by the Norwegian Research Council and conducted by SINTEF Ocean AS, NINA, NTNU Department of Engineering Cybernetics, Department of Biology at the University of Gothenburg, and the Swedish University of Agricultural Sciences. The main aim of the project was to acquire new knowledge on how the physiology and stress in salmon are reflected in observable behavioral patterns, forming the basis for developing real-time monitoring solutions for salmon in cages during production. Mortality during the growth phase in Atlantic salmon aquaculture is excessively high. The primary step toward improving this situation involves monitoring the physiology and stress of salmon during demanding operations (such as crowding) and regular production. Developing technologies for this purpose requires an understanding of how salmon physiology and stress manifest in data that can be electronically monitored using modern sensors. SalmonInsight aimed to address these questions through a series of experiments where physiological and behavioral data were collected simultaneously with real-time data collectible in fish cages using modern sensors. The SalmonInsight project included a Ph.D. candidate who developed a new implant for simultaneous measurement of acceleration, rotational rates, compass direction, magnetic field, temperature, electrocardiogram (EKG), and photoplethysmogram (PPG). This enabled the calculation of an activity indicator and a more robust method to estimate heart rate based on two independent measurement principles. The PPG measurements also demonstrated estimation arterial blood oxygen saturation, a feat never before achieved in fish. The initial experiment in the project was a controlled laboratory study where individual salmon were equipped with sensor tags measuring heart rate and swimming activity. The fish were subjected to artificial stress by repeatedly draining the holding tanks. Physiological samples were collected before tagging, before and after induced stress, and during the subsequent recovery period to correlate sensor data to physiological conditions. The results indicated that the fish's response to stress events led to changes in heart rate and swimming activity consistent with their physiological stress response measured through blood samples. This underscores the potential use of fish tags for real-time monitoring of stress in aquaculture fish. Additionally, these results provided valuable information about salmon recovery after surgical implantation of tags. The knowledge gathered in the lab experiments was pivotal in planning and executing subsequent trials. A similar experimental setup was used, observing tagged fish and untagged cohabitants before, during, and after crowding operations in meso-scale cages. In addition to tag data, physiological data were collected through blood samples. The data showed a clear increase in fish swimming activity in response to crowding, confirmed by blood parameters as a stress response, consistent with the lab experiments. However, heart rate interpretation was more challenging in this trial as clear patterns for this parameter in response to stress, seen in the previous tank trial, were not as evident. In the final trial, salmon were implanted with data storage tags and simultaneously equipped with intravascular arterial catheters, allowing repeated blood sampling from the same fish, facilitating closer comparison between sensor values from tags and physiological blood parameters. The fish were placed in a swim tunnel and exposed to different speeds. Data for heart rate, acceleration, and blood physiology were then compared with parameters collected via video analysis, including mouth opening frequency, gill frequency, and the fish's oxygen consumption measured with tunnel sensors. The results demonstrate that data from such loggers can be used to extrapolate several stress-related events, especially those involving increased activity, highlighting the potential of using biosensors for monitoring fish welfare. In summary, the project significantly contributed to the field of biosensors and implants for fish through the development of a new implant, knowledge transfer between institutes, installation of customized infrastructure, and facilitation of follow-up projects. Regarding dissemination, the project has resulted in 10 published articles, an additional 3 under peer review, and 3 more in preparation for submission in the coming weeks. Additionally, results have been presented at several national and international conferences and communicated through popular scientific journals.

The most tangible outcome a novel biosensing implant developed by the PhD candidate. The implant has the ability to measure a photoplethysmogram (PPG), allowing the assessment of arterial blood oxygenation and enabling a more robust heart rate measurement. This is especially relevant as the project outcomes showed that current heart rate measurements can be difficult to use as stress indicators. By supplementing PPG data collection in combination with measurements of acceleration, rotation rates, compass direction, magnetic field strength, temperature, and electrocardiogram (ECG) this novel tool may help to bridge the knowledge gap between measured behavioural and physiological parameters and stress. This offers new opportunities for research on the topic of stress, fish welfare, and fish physiology. As such it may support increased sustainability in aquaculture. For the collaborators, the project activities have held many advantages such as the transfer of knowledge between institutes as well as generations, ensuring sustained competence and recruitment into the research community. Moreover, the project created the opportunity to collaborate with institutes/universities in and outside of Norway, establishing good contacts between leading research specialists on the topic. The project has caused interest in the biosensing community through numerous publications and presentations at relevant conferences, leading to visits to relevant research groups outside the project group. Finally, the project facilitated the expansion of existing infrastructure for husbandry and experimentation of fish as well as the installation of new equipment (e.g., fish raceway including its own RAS system) which will accommodate future experiments in the field and increase the competitive advantage of the project partners. The far-reaching impacts of the project include the opportunity for follow-up projects, with some that have already been realised during the project period, building on the acquired competence. This competence further creates the foundation for future collaborations outside the project group. The novel biosensing implant is a tool that will not only be relevant in a basic research context but can facilitate testing of novel aquaculture technology while satisfying the recent regulatory requirements for such testing. As such it may be an important tool for the industry on their quest for future aquaculture technology. The combination of the large number of relevant sensors will eventually make the implant a good candidate for use on sentinel fish, i.e., individuals equipped with a biosensing implant to inform on the conditions experiences by the fish group as a whole. Moreover, the multi-sensory equipment will also make the implant attractive for use in species other Atlantic salmon, opening up for use in a wide range of fresh- and saltwater species.

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STIPINST-Stipendiatstillinger i instituttsektoren

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