Displaying items by tag: Algae
Microalgae are of fundamental importance for life in the oceans. With their photosynthesis they are the first link in the marine food chains upon which the existence of life in the oceans is based. Under certain conditions, however, uncontrolled mass development of the tiny algae can occur. The resulting algal blooms often have serious ecological and economic consequences and can even be toxic.
This article was featured in EM 1 / 2020.
In May 2019, over eight million farmed salmon suffocated in northern Norway as a result of a persistent algae bloom. The estimated economic loss from the 10,000 tonnes of farmed salmon is as much as 620 million Norwegian Kroner (EUR64m). The enormous algae blooms, which occurred due to warm weather, spread rapidly around Norway’s northern coast, sticking to fish’s gills and suffocating them. While wild fish can swim away from the lethal clouds of aquatic organism, farmed fish are trapped at the mercy of the algae. Harmful algae blooms occur when the normally occurring aquatic plants grow out of control due to warm weather. Some are attributing the severity of these algae attacks to climate change.
Omega-3 fatty acids from microalgae instead of fish oil
Fish oil is not available in sufficient quantities to meet the growing needs of the aquaculture and nutraceutical industries. Although essential omega-3 fatty acids are also to be found in microalgae, production capacity has so far been low. That is now changing, however, and developments in this field are making rapid progress. The first feeds for aquaculture with omega-3 fatty acids from algae are now available on the market.
Human beings – like fish – have to consume a certain amount of essential, long-chain, polyunsaturated fatty acids with their food every day in order to stay healthy and develop "normally". The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are particularly important. These are not produced in the body but must be obtained from food. Hundreds of scientific studies have revealed that EPA and DHA are of huge importance for the development and health of the brain, eyes and cardiovascular system.
With regard to their use in animal and aquaculture feed both of these fatty acids have up to now been obtained almost exclusively from marine fish oil sources. However, fish oil supply is limited because the available wild fish catches cannot be increased at will and they are also used more for direct human consumption. Global fish oil production is currently stagnant at around one million tonnes a year and is indeed tending to decline. This situation is already endangering the growth of aquaculture which uses almost three-quarters of worldwide fish oil production. Significant increases are not to be expected for the time being despite the fact that fish oil producers now also gain raw materials from previously unused reserves such as slaughterhouse waste and by-catches from the fishing sector which were previously discarded at sea immediately after the catch. It is estimated that 15 to 20 million tonnes more raw material could be taken from these sources each year. Hopes now also rest on the stocks of mesopelagic fish species which live in the oceans at depths of between 200 and 1,000 metres. Scientists have estimated their biomass at 10,000 million tonnes. If this is correct it would be by far the largest known fish resource. Access to these fish, however (they live at the upper limit of the deep sea) poses enormous risks to oceanic ecosystems because we still know far too little about the mesopelagic fish world to be able to use it sustainably.
The Norwegian Directorate of Fisheries has issued warnings that toxic algae blooms (Chrysochromulina leadbeaterii) are affecting an area of about 450 kilometres of the northern coastline of Norway.
September / October 2018 EM 5
Country profile: Latvia
Technology: Industry 4.0 conquers the fish processing sector - Automated processing lines take over from traditional manual work
Aquaculture: Algae and aquatic plants in global aquaculture
Events: Tuna 2018, WTO, Market Access. and Fish Trade