A growing demand for fish as a source of food, from an ever-increasing global population, has led to the over-exploitation of (and increased competition for) already diminishing fish stocks. Empty oceans mean empty stomachs – but also, in turn, empty pockets for those who rely on fishing for their livelihoods. A more sustainable approach is therefore urgently required.
Ending hunger requires adequate access to food not only on land, but also in the sea. Although modern food systems are predominately land-based, around three billion people around the world rely on fish as a major source of animal protein, with a further four billion eating seafood to supplement other protein sources. As well as calories, fish deliver vital vitamins and nutrients that are difficult to acquire through other food. Fishing is also essential to the livelihoods of around 12% of the global population, with 90% of these communities being dependent on small-scale fishers.
The conservation and sustainable use of oceans, seas and marine resources, as addressed by the United Nations’ Sustainable Development Goal 14 (SDG14), is therefore fundamental for ensuring a resilient and reliable food system – and integral to achieving the zero hunger goal of SDG2.
Today, fishing faces multiple challenges from a range of factors. Population growth and changing dietary patterns have caused the per capita consumption of fish to more than double over the past 50 years, with supply unable to keep up with demand – resulting in overfishing of marine stocks.
Due to irresponsible fishing practices, more than 30% of global fish populations have been exploited beyond their natural restoration rates. Increasingly selective consumer demand has exacerbated this, meaning that population numbers of several species (including Atlantic bluefin tuna and swordfish) have reached dangerously low levels, while the average size of some fish, such as cod, has markedly decreased over the past few decades.
Problems associated with overfishing are worsened by trawling, which can cause ecosystem destruction due to bycatch (the incidental capture and death of marine life), with 7.3 million tonnes of marine life – including fish, mammals, sea turtles and seabirds – being caught incidentally every year, and usually discarded dead as waste. Another issue is ghost fishing, whereby fishing gear that has been lost or discarded at sea continues to trap and kill marine life. Both bycatch and ghost fishing contribute to a decline in marine biodiversity, with adverse consequences for food systems.
Addressing the issues
There are legal solutions aimed at preventing over-exploitation of fish stocks – such as fishing quotas, seasonal fishing, protected areas, and controls around catch size of individual species. However, in order to be effective, these must be accompanied by the appropriate tools and technologies to monitor the catch (including its species composition, size, weight and location), while regulating irresponsible fishing behaviour.
While industrialised, commercial fishing threatens marine stocks on a global scale, more traditional fishing practices (often relied upon by in developing nations as a primary food source) are also being challenged by climate change, with the distribution of marine species being disrupted due to global warming. More innovative and resilient fishing gear is therefore required to maximise yields for subsistence fishers, as well as technology enabling easier identification of fish shoals. Smarter, more sustainable alternatives to ocean fishing, such as aquaculture, are also becoming increasingly important as a response to dwindling stocks.
Sustainable fishing through technology
Sustainable fishing practices are facilitated by numerous solutions, ranging from hi-tech, data-driven tools (such as deep vision systems or sonar devices used in large-scale ocean fishing), to refinements in the design of existing fishing gear. Regardless of the level of complexity, metals and minerals are indispensable in producing the tech that enables smarter, more efficient fishing.
Deep vision systems
A deep vision system makes it possible to check the physical features of fish without having to bring them aboard. LED lights are attached to the end of a trawl, and a high-definition camera photographs any marine life passing through. Images are then analysed by specialist software which determines the species and its size, while information on the timing and depth of the potential catch can be correlated with GPS data, thus showing the exact position of a given fish in the sea. The deep vision system could not be built without metals and minerals. For example, gallium, arsenic, and/or phosphor, gold, silver, and plastics are used to produce the LEDs. To build the camera lens, aluminium, titanium, stainless steel, and plastics are required. Deep vision tech is relatively costly, and not yet used commercially, but such systems have huge potential for the future.
The reliable measurement of catch weights on vessels at sea is a difficult task due to the movement of boats. A smart weighing system accounts for potential inaccuracies caused by such movement, enabling more exact determination of fish weight. Smart weighing systems may be integrated with RFID (radio frequency identification) tags – electronic devices attached to the box of captured fish. Exchanging data with an RFID reader through radio (electromagnetic) waves, RFID tags consist of a chip (or integrated circuit) and an antenna. The chip is made of silicon (or in some cases sapphire) with a layer of copper insulation, while copper is used for the antenna. RFID tags also allow for the sharing of information such as vessel ID, voyage, species, weight, size, or date of capture – hence making it easier to abide by fishing quotas and other regulatory requirements.
Technological solutions for monitoring the behaviours of individual vessels in a fishing fleet can in general be divided into collaborative tools (relying on the willingness of shipping captains) and non-collaborative (relying on the actions of authorities). Alongside smart weighing and RFID tags, other examples of collaborative tolls are Vessel Monitoring Systems (VMS) and Automatic Identification Systems (AIS), while non-collaborative tools include optical or radar satellites. What they all have in common is a reliance on connectivity driven by the 'Internet of Things', with satellites playing a key role. The data sent via satellites includes the position, date, time and speed of a vessel, determining whether it is fishing or traversing a specific area. Satellites come in many shapes and sizes, but usually comprise two main parts – an antenna used for sending and receiving information (made of copper, aluminium or stainless steel), plus a power source (which may be a solar panel or a battery).
Acoustic methods provide the ability to measure the quantity, species and size of a fish school – or even size of individual fish within the school – without catching them: saving time, fuel, and money. Sound Navigation and Ranging (commonly known as SoNaR) technology is one of the most important developments in modern fishing. It has greatly reduced dependence on fisherman’s intuition, reduced time spent on searching operations and cut the unit costs of harvesting. The main component of sonars is an electro-acoustic transducer, able to send signals and then listen to the returning echo, thus determining the distance to fish and other relevant information. These electronic pulse signals are into sounds via a piezoelectric or magnetostrictive material in the centre of a transducer. Typically, transducers have a steel housing that encloses the drive coil and the core, while the magnetostrictive effect is enabled by several common materials like iron, cobalt and nickel, as well as rare earth materials like lanthanum and terbium.
Aquaculture –the active breeding, rearing and harvesting of fish – is becoming increasingly important as an alternative to ocean fishing, and is currently the fastest-growing animal food production sector in the world. It is predicted that, by 2030, aquaculture will provide nearly two-thirds of the fish for human consumption.
Also known as aqua farming, aquaculture depends on a variety of systems, including netcage (such as pontoons, nets and boots), recirculation (filters, conditioners, tanks), incubation (incubators, jars, trays), feeding (solar, pendulum, clockwork), aeration (injectors, blowers, diffusers), monitoring (testers, meters) and processing machines (scalers, filleters, smokers), while smart digital tech solutions also play a key role. Metals and minerals are essential for building all of these devices. For example, incubators are made of strong non-toxic plastics and aluminium or stainless-steel frames. The ultraviolet system used for water disinfection comprises a reactor chamber (usually constructed of stainless steel), UV lamp (containing glass and mercury), quartz sleeve, and controller unit, the pools for holding fish require a strong galvanized iron wall, and aquaria utilise materials including glass, aluminium and PVC.
Improving traditional fishing
In response to climate change exercising pressure on smaller-scale, artisanal fishers, a crucial role is played by simple and relatively cheap solutions to improve the design and efficiency of fishing boats, nets and other gear. Extremely lightweight fibre fishing nets (constructed of a carbon fibre or fiberglass composite material) are one such development, while advances in refrigeration, ice-making and fish processing equipment have allowed vessels to remain at sea for extended periods of time. Motorised canoes and boats (which could not be produced without raw materials such as aluminium, copper, and iron) also enable subsistence fishers to travel longer distances in search of displaced fish – thus increasing the size of catch, reducing hardship and contributing to more sustainable fishing.