Fisheries and aquaculture 

Over 500 million people depend, directly or indirectly, on fisheries and aquaculture for their livelihoods. Fish also provides essential nutrition for 3 billion people and at least 50 percent of animal protein and essential minerals to 400 million people in the poorest countries. However, climate change is bringing about huge challenges to these resources. Production systems and livelihoods, already in crisis from over-fishing, poor management and impacts from other terrestrial anthropogenic influences, are likely to succumb further as the frequency and intensity of storms increase and extreme weather events become more common. Fishers, as well as other community members, will be at greater risk of losing their lives and assets, such as boats, fishing equipment and aquaculture infrastructures. Adaptation strategies will need to be context and location specific and to take into account both short-term (e.g. increased frequency and intensity of extreme events) and long-term (e.g. reduced productivity of aquatic ecosystems) phenomena. Strategies to increase resilience and adaptive capacity will require wide-scale implementation and adoption of measures and practices that adhere to the principles of the Code of Conduct for Responsible Fisheries.

Low energy efficient aquaculture

The farming of seaweeds, oysters and clams constitute the largest proportion of mariculture production worldwide. The culture of these groups requires minimal energy inputs and, therefore, has a relatively small carbon footprint. Moreover, the rapid turnover in seaweed culture, approximately three months per crop (in the tropics) with yields of over 2 500 tonnes per ha, far exceeds the potential carbon uptake that could be obtained through other agricultural activity for a comparable area. Additionally, such systems can filter nutrients and provide a "cleaning service" to coastal marine environments.

The farming of seaweed has expanded rapidly in recent decades as demand has outstripped the supply available from natural resources. Annual production value are estimated at US$5.5-6 billion; with commercial harvesting occurring in about 35 countries, spread between the Northern and Southern Hemispheres, in waters ranging from cold, through temperate, to tropical. China is the largest producer of edible seaweeds. About five million tonnes (mostly for kombu) is produced from hundreds of hectares of Laminaria japonica that is grown on suspended ropes in the ocean. Other seaweeds, such as kappaphycus alvarezii and Eucheuma denticulatum, originally harvested from natural stocks in Indonesia and the Philippines for the production of thickening and gelling agents (Carrageenan), are now cultivated and production has also spread to other countries, including Tanzania (Zanzibar), Viet Nam and some of the Pacific Islands. 

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Aquasilviculture

Another environmentally-friendly and GHG mitigating mariculture system is aquasilviculture, the integration of aquaculture and mangrove forestry. Such systems are commonly used in Indonesia and Vietnam and in the early stages of development in other countries such as Hong Kong, the Philippines, and Malaysia. The approaches differ among and within countries but mainly constitute the integration of mangrove ponds and pens for fish and crabs (Primavera, 2000). Such systems not only sequester carbon, but they are also more resilient to shocks and extreme events and also lead to increased production due to improved ecosystem services. A good example of the benefits of aquasilviculture can be seen in the introduction of the system in the tambak region of Java, an area of over 300 000 ha of extensive ponds which lacked mangroves. The introduction of mangroves led to the increase in production, in food supplies and contributed significantly to the socio-economic well-being of the coastal rural population (Sukardjo 1989). The system was therefore more profitable than just direct planting of mangrove trees, and the net financial benefits to the reforestation programme of the State Forestry Corporation was considerable (Sukardjo, 1989). 

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Low Energy Fuel Efficient (LIFE) Fishing

Well-designed and responsibly-used passive fishing gears such as gill nets, pots, hook and lines and traps can reduce the requirement for fossil fuel consumption by as much as 30-40 percent over conventional active fishing gears, such as trawls. Moreover, the use of bio-degradable materials can minimize the amount of ghost fishing when fishing gears are inadvertently lost as a result of bad weather. New designs of selective fishing gear can reduce the capture of juveniles and other forms of bycatch as well as reducing discards. Innovative technologies such as GPS and echosounders can also be used to ensure that fishing gears are not set on vulnerable or sensitive habitats. Other innovations in design of vessels and fishing equipment coupled with safety training can minimize accidents and loss of life at sea and assist with fishing losing its reputation of being the most dangerous occupation in the world. 

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last updated:  Wednesday, December 29, 2010