Showing results for: Primary production: Aquaculture and fisheries
Fish and seafood constitute an important part of diets around the world and are a key source of protein and essential fatty acids (such as omega 3). Over the past 50 years however, overfishing and destructive fishing techniques have caused dramatic reductions in wild fish stocks. Around 85% of fisheries are now fully exploited or overfished, and many of the ecosystems associated with fishing activities have been severely damaged. With growing populations and increasing per capita protein demand, producing sufficient fish to fulfil demand has prompted a focus on aquaculture: the farming of fish and seafood. Aquaculture is the most rapidly expanding subsector of the animal production sector and it now exceeds capture fisheries as an aquatic food source. While there is significant potential for aquaculture to reduce some of the pressures on wild fish stocks, the sector also generates its own environmental problems. The farmed aquatic sector is however hugely diverse – from modern closed recirculating systems through to traditional integrated ones (involving production of both fish, livestock and agriculture) – making it difficult to generalise.
The vast majority of industrial fishing (defined as fishing vessels of over 24 metres) is done by vessels that are registered to relatively wealthy countries, according to a recent paper. Vessels registered to high income and upper middle income countries (according to World Bank classifications) accounted for 97% of industrial fishing effort in international waters and 78% of industrial fishing effort in the national waters of poorer countries. China, Taiwan, Japan, South Korea, and Spain together account for most of the fishing effort.
Fishers increase their fishing activity prior to the establishment of a new marine reserve, a new paper claims. The study used satellite data to study one particular marine reserve, the Phoenix Islands Protected Area (PIPA). While fishing effort dropped to almost zero after the marine reserve was established, fishing effort prior to the reserve’s establishment was 130% higher than in a control region (where no reserve was planned).
Attaching green light emitting diodes (LEDs) to gillnets (vertical fishing nets that catch fish behind the gills) reduces the number of guanay cormorants accidentally caught by 85% relative to control nets with no lights, reports a recent paper. A previous study of the same fishery has shown that illuminating nets can reduce bycatch of green turtles by 64% without reducing catch rates of the target species (the current paper did not specify catch rates of the target species). The authors hypothesise that it may be possible to tailor the wavelength of light to attract or repel specific species, according to a fishery’s needs.
Farmed fish are often fed on forage fish (such as anchovies and sardines) caught from the wild. A new paper points out that demand for forage fish to support aquaculture production is forecast to grow beyond the maximum sustainable supply level. The authors calculate that demand for forage fish could be reduced to below the maximum supply limit by combining a number of measures: reducing use of forage fish in land-based agriculture, replacing some forage fish with fish trimmings from processing, and reducing the proportion of forage fish in the diets of non-carnivorous farmed fish.
The FAO has released a report on the current state of knowledge on how climate change will affect fisheries and aquaculture, including mitigation and adaptation options. The report finds that “climate change will lead to significant changes in the availability and trade of fish products”. Marine catches could decrease by 2050 in the tropics and rise in some high latitude regions, with a global decrease in Exclusive Economic Zones of 3% to 12%. Inland fisheries in Pakistan, Iraq, Morocco and Spain may come under greater stress, while those in Myanmar, Cambodia, the Congo, the Central African Republic and Colombia may remain under low stress in the future.
A new paper finds that the global marine fishing fleet produces greenhouse gas emissions equivalent to 4% of the total emissions from global food production. The types of fisheries with the highest emissions intensity per unit of catch are those using motorised craft (vs. non-motorised), those harvesting for human consumption (vs. catches used for meal, oil or non-food uses), fishing for crustaceans (vs. other species types) and fisheries in China (vs. those in other regions).
The FAO has released its 2018 report on world fishery and aquaculture statistics. Key findings include that fisheries output peaked in 2016, having remained approximately static since the late 1980s, while aquaculture production is rising, as shown in the figure below. In 2015, fish accounted for around 17% of global animal protein consumption. One third of fish stocks are currently overfished, although progress has been made in the United States and Australia in increasing the proportion of fish stocks that are sustainably fished.
Our thanks go to FCRN member Emma Garnett for bringing to our attention a recent paper that investigates how land use could change if consumption were to shift away from meat and towards seafood from aquaculture. Aquaculture systems frequently use feed that is made from land-based crops. The paper studied two aquaculture-heavy scenarios (one using only marine aquaculture, and one using the current ratio of marine to freshwater aquaculture) where all additional meat consumption in 2050 (compared to today) is replaced by aquaculture products. Compared to a business-as-usual scenario for 2050, the aquaculture scenarios use around one-fifth less land to produce feed crops, because of the relative efficiency of aquatic organisms (compared to land-based animals) in converting feed into food that can be eaten by humans.
The book “Agricultural Development and Sustainable Intensification: Technology and Policy Challenges in the Face of Climate Change”, edited by Udaya Sekhar Nagothu, examines different approaches to sustainable intensification and presents case studies from around the world.
This book, edited by Faisal I. Hai, Chettiyappan Visvanathan and Ramaraj Boopathy, discusses the social, economic and environmental sustainability implications of various aquaculture practices.
Building UK fish stocks up to their maximum sustainable yields could increase fish catches by 27%, create 5,100 new jobs and add £319 million to the UK’s GDP, NGO Oceana reports. Oceana points out that Brexit may provide a window of opportunity to change the UK’s fishing practices for the better.
Genetically modified salmon could potentially be on the US market by 2019.
This paper presents the findings of a large-scale study which used global tracking data on sea-going vessels to characterise the scale, distribution and drivers of the global fishing effort.
Fish are generally seen as more efficient in converting feed into food than land-based species, but, according to a new paper, this conclusion does not hold if the retention of protein and calories is accounted for using a different measure.
Finless Foods hopes to make laboratory-cultured bluefin tuna the same price as the conventional product by the end of next year (bluefin tuna, threatened by overfishing, can sell for around $380/lb).