As the world’s population grows, the pressures put on our limited food sources are increasing. With each passing decade, fewer fish are available for fishing.
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Current data estimates that roughly 85% of the world’s fish stocks are either depleted, over-exploited, fully explored, or recovering from exploitation. To meet the continuing needs of the growing population, scientists have developed technology to allow commercial fishing fleets to increase their fishing power.
Innovative sensors such as GPS systems, fishfinder sensors, echo-sounders, and acoustic cameras have led to a 2% yearly increase in commercial fleets’ capacity to capture fish. Here, we discuss these sensors in detail, explain how sensors are used for catch inspection, and consider the balance between obtaining enough food to feed the global population while protecting the ocean’s fish reserves.
How are Sensors Used in the Fishing Industry?
GPS systems are rapidly becoming the standard positioning indicating system used onboard commercial fishing fleets. In this application, GPS sensors are used not only to inform the fishermen where in the ocean they are located but they are also used to help track ‘hotspot’ areas as well as tack fish migrations. This helps fleets to successfully locate fish more efficiently, gaining larger hauls.
A fishfinder sensor uses a transducer to calculate water depths, analyze bottom features, and detect fish targets. The transducer scans the water by using piezoelectric crystals to send a beam of sonar pulses through the water. When these beams find an object, the wave is reflected back to the transducer, which then passes this information on for further interpretation.
Echo sounders work in a similar way to fish finders. They emit sound pulses into the water, which are then reflected back when they hit solid objects (such as fish, or the sea floor). These sensors help fleets locate shoals of fish.
Acoustic cameras are a newer technology that helps fleets locate fish even in turbid, challenging environments. Acoustic cameras can gather vital information when visibility is poor, increasing the knowledge of fish in their habitat. As a result, less effort is needed to find fish, and their migration habits can be easily tracked. This technology is often used for performing surveys of fish populations to gather long-term information on the activities of the fish.
How are Sensors Used in Catch Inspection?
Catch inspection is an important process in the commercial fishing industry. It authenticates seafood species, verifies tonnage, helps companies adhere to vessel compliance and confirms the origin of seafood harvested.
There are several technologies currently available on the market that are designed specifically for catch inspection. Often, these technologies are developed to inspect a certain species of fish. The Hermasa Tunascan, for example, automatically classifies tuna by species, size and quality, using a 3D laser scanning system.
To do this, the Tunascan is first loaded with tuna, regardless of its size, species, or degree of damage. The tuna are then separated and correctly aligned before they reach the 3D scanning area. Next, each piece of tuna is scanned in succession.
Artificial intelligence algorithms and neural networks process the information obtained by the scan to determine the species, size or quality of the fish. Lastly, the fish are allocated to distinct containers, depending on their species, size, and quality.
The benefits of such systems are numerous. Most importantly, they remove human error from the equation. Secondly, they offer a fast and efficient method of classifying and inspecting fish, saving companies time and money. Third, they allow for automation separation of the fish, preparing it to be shopping out in classifications of species, size, and quality.
Future Outlook on Sensors in the Fishing Industry
Currently, there are many technologies in development to help improve the fishing industry. Norwegian company Lerøy, for example, launched a pilot study several years ago, testing the efficacy of its sensors in collecting data in real-time about fish behavior.
The sensors, which are attached directly to the bodies of salmon caught in cages, use an underwater wireless network to collect and transmit data to farm managers. The sensors have so far been proven effective at determining fish health.
In addition, Lerøy is also working on hyperspectral cameras to measure the quality of fish. The cameras determine the quality of the meat before it is filleted, helping to prevent poor-quality fish from entering the market.
Another system is currently in development for determining the freshness of mackerel. The novel system, reported on in the journal Food Science and Biotechnology, uses an optical inspection system (OIS) that finds correlations between the light reflection intensity (LRI) of mackerel eyes and the volatile basic nitrogen content (VBN) – a measure of quality and freshness of fish.
In the coming years, there will likely be further developments in the field, given the importance of finding and sourcing enough fish to meet rising demand as well as streamlining the quality assurance process.
References and Further Reading
Choi, J., Jang, M., Hong, C., Lee, J., Choi, J., Kim, K., Xu, X., Ahn, D., Lee, M. and Nam, T., (2019) Novel application of an optical inspection system to determine the freshness of Scomber japonicus (mackerel) stored at a low temperature. Food Science and Biotechnology, 29(1), pp.103-107. https://link.springer.com/article/10.1007/s10068-019-00639-z
Hermasa. Tunascan. 3D Laser system: Automatic tuna classification system [online]. Available from: https://hermasa.com/wp-content/uploads/woocommerce_uploads/2019/01/automatic_tuna_classification_tunascan-1.pdf [accessed May 2022]
Palomares, M. and Pauly, D., (2019) On the creeping increase of vessels’ fishing power.. Ecology and Society, 24(3). https://www.ecologyandsociety.org/vol24/iss3/art31/
Aaron Orlowski. (2019) Seafood Source. Lerøy testing project to detect salmon health with implanted sensors [online]. Available from: https://www.seafoodsource.com/news/aquaculture/ler-y-testing-project-to-detect-salmon-health-with-implanted-sensors [accessed May 2022]
IMV Europe. Norwegian fish filleting gains hyperspectral quality measure [online]. Available from: https://www.imveurope.com/news/norwegian-fish-filleting-gains-hyperspectral-quality-measure [accessed May 2022]
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