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October 17, 2025
First Week of Scientific Adventure at Hólar for the 2025–2026 Aquaculture Diploma Cohort!
The new 2025–2026 cohort of the Aquaculture Diploma officially got their hands wet!
Students participated in their very first onsite practicum as part of the Fish and Water course — a week full of experiments, discoveries, and a touch of scientific excitement. Gases in Aquaculture : Essentials in Action The week began with an engaging lecture by Paul on a topic as subtle as it is essential: gases in aquaculture. Afternoon: Time for Practice!Students applied their newly acquired knowledge in an Excel practical session, performing gas concentration and saturation calculations based on temperature and salinity. Fish Respiration: Hands-On Experience Next, it was time for fieldwork (and a bit of action!) with David and Marie for a series of practical experiments. Students started by measuring and weighing a group of fish, then monitored their oxygen consumption over time. By taking regular measurements of dissolved oxygen in the tank, they could observe firsthand how the fish “breathe” and why oxygen is a critical parameter to monitor in aquaculture. To go even further, Alex, David’s master student, presented a more precise method for measuring respiration at an individual scale: the Standard Metabolic Rate (SMR). An impressive demonstration highlighting the importance of advanced tools to understand fish physiology. Comparing Different Water Sources To complete their learning, students collected various water sources around Hólar and analyzed them for characteristics such as ammonia (NH₃/NH₄⁺), nitrites, nitrates, and alkalinity. This scientific investigation allowed them to observe differences in water quality depending on the source and understand why these parameters are crucial: ammonia, nitrites, and nitrates reflect the presence and transformation of nitrogen from fish waste, decomposing organic matter, and natural or anthropogenic inputs. Students then explored the other side of respiration: carbon dioxide (CO₂) To monitor the effect of a degasser on CO₂ removal, they measured pH, temperature, and alkalinity, allowing them to calculate CO₂ concentration in the water. They also measured oxygen over time to understand the relationship between oxygen and CO₂. This parameter is critical to monitor and must be kept at low levels to ensure the health and well-being of fish in an aquaculture system. Influence of Temperature and Salinity on OxygenTo conclude the practicum, students tracked oxygen concentration over time in different types of water: cold freshwater, warm freshwater, cold saltwater, and warm saltwater. This experiment helped them understand the effect of temperature and salinity on oxygen solubility and its importance for fish health in aquaculture. A Successful Report and Presentation Divided into small groups, students then synthesized their results into a scientific report and presented their findings to instructors and classmates. A demanding exercise, but brilliantly executed — congratulations to them! A Full, Intense… and Exciting Week! Between theory, practice, water manipulations, measurements, calculations, and fish respiration, this first week of Fish and Water offered students a complete immersion in the fundamentals of water quality in aquaculture. A rich experience that will enable them to confidently and accurately manage aquaculture systems they encounter throughout their studies — and in their future careers. The 2025–2026 cohort is off to a strong start and promises great things! |
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