As our planet reaches a population of 7.7 billion people, which we expect to grow by more than 25% to 9.7 billion by 20501, it becomes increasingly critical to invest in solutions that enable us to feed the planet sustainably. Since the 16th century, fishing vessels have been going out to sea and catching fish for human consumption. We started fishing in waters close to shore with limitations such as boat size and the ability to keep products fresh. As technology advanced, we were able to fish longer, catch more and move further offshore to more abundant populations. As the demand increased, so did the advances in technology and we were becoming increasingly proficient at fishing more out of our oceans. Our planet however, has limited natural resources and through modern science and research, we are beginning to understand the impacts of losing wild fish stocks that are unable to sustain themselves at the rate we are harvesting them. When we take stock of our global marine fisheries, the trends we observe are extremely concerning. The percentage of overfished and fully fished stocks are increasing and the number of available, non-exploited stocks are decreasing (Figure 1). What happens when we run out of stocks to fish? What happens when there’s nothing left to exploit in order to feed our ever-increasing populations?
Figure 1: Global Trends in the State of World Marine Fish Stocks Since 1974
The great Jacques Cousteau once said,
“We must start using the sea as farmers instead of hunters. That is what civilization is all about – farming replacing hunting”.
Intensive agriculture has been around for hundreds of years. Hundreds of years to practice and perfect it into a fine science. When we compare this to intensive salmon aquaculture, which only started in the last 50 years, it is clear that the aquaculture industry is still in its infancy. Even without hundreds of years of practice and development, salmonids maintain the lowest feed conversion ratio of any livestock (Figure 2), unless we include crickets but surely, we are not quite ready to trade delicious smoked salmon for a plate of fried crickets- not yet at least. Just as we have put development and effort into improving agricultural practices, we have a unique opportunity to develop sustainable aquaculture practices and in turn, release the intense pressure we place on our oceans.
Figure 2: Feed conversion ratio for 4 commonly farmed animals, fish, chicken, pig and sheep.
The habitat in which fish live is different from the environment agricultural livestock experience. Their environment is one that is extremely familiar to us; the one we experience every day. A coworker explained this phenomenon in quite simple but eloquent terms. He said, “If we’re hot, the cows probably are too!” That intrinsic knowledge has allowed us the capability to care for animals farmed on land with ease. This fact explains exactly the challenge we face today. When farming fish in an environment that is largely foreign to us, how can we ensure the welfare of the fish while still maximizing production rates to meet the increasing demands of sustainable protein sources? The answer lies in data.
Up until quite recently, data collection methods for salmon farming were very primitive. In order to determine the welfare of the animals and acceptable feeding windows, workers needed to measure dissolved oxygen levels on the farm. Site workers would typically use a single handheld instrument to take measurements from a single location, multiple times per day. This allowed for very reactive farming practices and offered no insight into conditions between measurements. Looking at variability of dissolved oxygen levels on a single farm, we know conditions can change drastically within a single day not only across a farm, but within individual pens as well. In order to provide the best care for farmed fish, it is critical to monitor all pens continuously. Each cage is experiencing its own individual microclimate depending on the biomass, current speed and direction, dissolved oxygen levels etc., and it is necessary to treat each cage individually to provide maximum care and minimize food waste. With the advances in technology, it is now possible to outfit an entire farm with dissolved oxygen sensors that collect data 24/7 and give users data access in real-time! This capability has completely revolutionized the way farms operate and enables farmers to make educated, data-driven decisions for day to day operations.
Not only does this technology allow users access to their data anytime, from anywhere in the world, it enables the capability to observe trends over time and begin to understand what conditions might be the precursor to low or high dissolved oxygen events. As technology advances, that which uses machine learning or advanced algorithms will lead to development of software able to predict future conditions; farming will no longer be reactive, but proactive. If farmers can predict low oxygen conditions, they can take preventative actions to aerate or oxygenate the water accordingly. Feeding windows will rely solely on the hunger levels of the fish and not on environmental constraints. If farmers can maximize these feeding windows, they can complete grow-out cycles in the shortest amount of time, which can have powerful cost benefits. A shorter grow-out cycle means less feed used and because feed is the single greatest cost variable, this can have significant impacts on productions costs. A shorter grow-out cycle will also limit the window for sea-lice exposure and reduce the fallowing period between production cycles2.
Dissolved oxygen may be the most important parameter to measure for fish welfare and feeding, but there are others to consider when characterizing their living environment. These parameters interact with each other, affect dissolved oxygen levels and can assist in understanding why certain cages exhibit better dissolved oxygen levels than others. By collecting this data continuously, we can provide more information to models that predict environmental changes, making them stronger and more accurate. Information such as current speed and direction through the water column, wind speed and direction, salinity, temperature, chlorophyll, blue-green algae and turbidity are some of the data we can collect in real-time, to enhance our ability to characterize the environment on a farm.
High current speed from tides or prevailing ocean currents can increase dissolved oxygen levels by a flushing mechanism of bringing in fresh, oxygenated water through a farm system. The speed and direction of these currents will dictate how water flows through a farm system and give insight into why some pens maintain high dissolved oxygen levels. Wind speed is another factor that can explain dissolved oxygen levels. Wind creates waves, which churn the water and act as a natural aeration system. The temperature and salinity of the water determines the amount of oxygen the water can hold- making it important to measure all of these parameters simultaneously to understand the system holistically. Chlorophyll and blue-green algae sensors target phytoplankton concentrations in the area. These biological parameters can have disastrous impacts on farmed fish and it is imperative to understand the relative concentrations around farms. These sensors target fluorescent pigments (chlorophyll and phycoerythrin) within phytoplankton and are used as a proxy for phytoplankton concentrations. In large concentrations known as blooms, phytoplankton can completely deplete oxygen levels in an area at night as they go through the respiration process. Blue-green algae, a sub-category of phytoplankton, have the potential to produce toxins, which in large concentrations known as harmful algal blooms, can cause mortality of fish on an entire farm.
Figure 3: Phytoplankton bloom seen from space in the Barents Sea, north of Norway courtesy of MODIS (Moderature Resolution Imaging Spectroradiometer) on NASA's Aqua Satellite. Captured July 27, 2004.
The ocean is a complex environment that is surprisingly foreign to us as a species who relies so heavily upon it. The only way we begin to understand the dynamic subsea conditions is with advanced technology and sensors that allow for continuous measurements. In the age of big data, we can transform industries by providing valuable insights that we would otherwise be unable to make without computational power. As the world’s population grows and society develops practices that will enable us to sustain this growth, we need to continue to invest in smarter farming practices. Not only does this help solve the major global issue of feeding an exponentially growing population, but in turn, relieves the pressure of our oceans’ natural resources. Aquaculture is already becoming an integral part of feeding the planet. In 2014, for the first time ever, the global consumption of farmed fish was greater than wild-caught4. If we are going to meet the demand for sustainable protein sources for ~10 billion people, efficient farming practices are going to be instrumental and smart, data-driven aquaculture is the answer…or we can always switch to a cricket-based diet!
1 United Nations, Department of Economic and Social Affairs, Population Division (2017). World Population Prospects: The 2017 Revision, Key Findings and Advance Tables. ESA/P/WP/248.
2 Bjørndal, T., & Tusvik, A. (2017). Land based farming of salmon: economic analysis. (ISSN: 2464-3025). Retrieved from Norweigian University of Science and Technology, Department of International Business, February 19, 2020.
3 We acknowledge the use of Rapid Response imagery from the Land, Atmosphere Near real-time Capability for EOS (LANCE) system operated by NASA's Earth Science Data and Information System (ESDIS) with funding provided by NASA Headquarters.
4 FAO, 2014. FAOSTAT. Food and Agriculture Organization of the United Nations, Rome, Italy