Tracking Fish Weight, Length and Growth in Aquaponic Systems

Aquaponic systems require producers to track fish, plant, and system data. These components work together and depend upon each other to form a successful aquaponic operation. Specific factors while monitoring fish are tracking weight and length. Tracking these averages of a fish class is important because the measurements are an indicator of fish and system wellbeing. Other reasons for tracking these measurements include health indications, known growth rates, and business planning. **Tracking weights and lengths helps producers streamline their systems, plan more effectively for future seasons, and grow more efficiently. **

Observing Fish When Weighing and Measuring Fish

During the weight and length collection process, producers have the opportunity to examine their fish up close. Producers can use that time with the fish to observe any physical ailments or abnormalities and compare fish to one another. Producers should examine general coloration, gill and fin quality, coloration and structure, and look for other fish health indicators. If disease indicators are present, producers should be wary about spreading disease from fish to fish or system to system.

Producers must also be careful not to cause any disease outbreaks or mortalities when collecting measurements. This process can be stressful for fish as they are being handled and removed from the water. Producers should aim to keep a fish out of the water for as little time as possible and limit unnecessary handling.** Improper holding techniques and gripping the fish too tightly can damage their mucous membranes, leaving them vulnerable to opportunistic bacteria, fungus, protozoa, and parasites.** Fish can also sustain injuries if roughly handled or dropped. Producers should also be mindful of the ambient air temperature and water temperatures when sampling. Higher or abnormal water temperatures within your system leave the fish prone to stress and additional disease outbreaks. 

Feed Conversion Ratio in Aquaponics

Tracking the weights and lengths of a fish class will allow producers to determine the rate and amount to feed the fish. Having a reliable data trend of fish growth is the foundation of feeding as it shows the feed conversion ratio. The feed conversion ratio is the rate at which animal feed converts to the desired output. In some aquaponic cases, the desired product is a market-sized fillet. Without any data to inform decisions, producers would be estimating the amount to feed their fish.

There are consequences for underfeeding and overfeeding the fish. Feeding too little wastes grow out time, resources, and money. Underfeeding leads to increased competition between fish, starvation, malnutrition, and abnormal development as the fish are not getting essential nutrients. The overall nutrient availability within the aquaponic system would also suffer as the plants would not have enough nutrients to survive. Overfeeding also leads to wasted money and time. Feeding too much or too frequently can lead to increased ammonia and fish waste and decreased water quality. The fish will not finish all the food, leading to wasted resources and unnecessary expenditures.  

Understanding Growth Rates in Aquaculture

Knowing fish growth rates within a particular time frame will help producers for business purposes. Growth rates determine the amount of food to purchase, when to make that purchase, and allows producers to predict when the fish will be ready for market. This data informs producers of how much the fish will eat and grow during different life stages and under various temperature conditions. More data collected equals a more informed and prepared producer.  For example, fish can only eat food types and sizes consistent with their size (e.x. 1mm, 2mm, 3mm pellets). A swim-up fry could never consume a 5mm pellet. Specific feeds can degrade over time and lose essential nutrients. Producers can use the weight and length data to predict and plan out when to purchase the food or how to store the bags. Ultimately, knowing the weight and length growth rates can help keep businesses organized and on a schedule that limits the amount of money wasted and space used.

We at Aquaponic AI offer aquaponic and aquaculture farmers the technology necessary to properly track system parameters using notebooks, alerts, reminders, and numerous other features. Notebooks are a secure location where producers can input and store data. Key notebooks available to producers include weight and lengths, water quality, water temperature, and total ammonia, to name a few.

Once data is collected and input into the notebooks, the software automatically generates graphs that show system trends. The graphs are easily comparable so producers can determine if components should remain constant or if changes are necessary to enhance efficiency and growth rates. The weight and length data can be used in combination with other tracked aspects such as water temperature and feed conversion chart to make informed decisions. This user-friendly technology helps to streamline farms by removing data collection, input, and analysis barriers.