Sustainable aquaculture and aquatic resources management

By Barry Costa-Pierce, 22/09/2010 | .mp3, 14.55 MB | 1047 views | Download soundtrack Stream soundtrack
Programme: Global Conference on Aquaculture 2010

The Bangkok Declaration expressed the need to develop resource-efficient farming systems that make efficient use of water, land, seed and feed inputs by exploring the potential for commercial use of species feeding low in the food chain and fully utilising enhancement techniques. Key resources that are used in aquaculture and a summary of how each has changed over the last decade are summarised in a table below.

During the past decade, resource use in aquaculture began to be measured in terms of FIFO (Fish In Fish Out) ratios and by measuring efficiencies in water, land use and carbon footprinting as new metrics for measuring resource efficiency and stewardship. Studies indicated finfish aquaculture of tilapia, catfish and Pangasius catfish taken together were comparable to poultry farming in terms of FCRs (1.8 vs. 2.0), water (2,800-6,300 litres/kg vs. 3,500–4,000), land use efficiency (7,941 vs. 7,946 kg/ha/year), and carbon footprint 2.0 vs. 1.8 kg CO2/kg product).

A decade ago, published values of FIFO were as high as 5 kg. Rapid advances in aquaculture feeds, feed management technologies and nutrition science have decreased FCRs to ~1.5:1 for farmed marine fish and ~1.2:1 for farmed salmon. Thus, overall FIFO calculations indicated that global aquaculture now has a FIFO ratio of 0.52 (e.g. that for each tonne of wild fish caught, aquaculture produced 1.92 tonnes of aquaculture products), despite some groups as salmonids, eels, marine fish and shrimp still having an FIFO >1. Current projections are that over the next decade, fed aquaculture will use even less marine fish meals/oils, while overall aquaculture production continues its rapid growth. Just recently, EWOS announced that it will be accelerating research to measure the “marine protein and oil dependency ratios” for farmed species, with the goal of reducing these to less than 1.0.

Constraints to the expansion of global aquaculture are different for fed and non-fed aquaculture. Over the past decade for non-fed, shellfish aquaculture there has been a remarkable global convergence around the notion that user (space) conflicts in shellfish aquaculture can be solved due not only to technological advances, but also to a growing global science/NGO consensus that shellfish aquaculture can “fit in” in an environmentally and socially responsible manner, and into many coastal environments, the vast majority of which are already crowded with existing uses. Factors contributing to this are the: (a) development of submerged technologies; (b) scientific findings and reviews demonstrating the environmental benefits of shellfish aquaculture in providing vital ecosystem and social services such as nutrient removal and habitat enhancement; (c) research on natural and social carrying capacities for shellfish aquaculture and sophisticated, collaborative work group processes; (d) development of, and wide use by industry of better management practices; (e) diversification of traditional wild-harvest fishing/shellfishing families into shellfish aquaculture as part-time enterprises, breaking down barriers between fishing/aquaculture user communities; and (f) publication of global comparisons with fed aquaculture indicating a strong movement in shellfish aquaculture towards an adoption of ecological approaches to aquaculture at all scales of society.

Over the past decade, new, environmentally sound technologies and resource-efficient farming systems have been developed, and the integration of aquaculture into coastal area and inland watershed management plans has been achieved, but are still not widespread. These aquaculture ecosystems are highly productive, semi-intensive enterprises that are water and land efficient, and are net energy and protein producers that follow design principles similar to those used in the fields of agroecology and agroecosystems. Good examples exist for both temperate zone and tropical nations with severe land, water and energy constraints. In Israel, highly efficient, landscape-sized integrations of reservoirs with aquaculture and agriculture have been developed, as well as highly productive, land-based aquaculture ecosystems for marine species. In Canada, development of integrated mariculture systems (IMTA) for environmental mitigation has led to studies showing greater economic returns and social acceptability for large-scale industrial aquaculture. Siting of cages in enclosed seas such as the Mediterranean Sea remains controversial, especially when it has been estimated that cage aquaculture facilities contribute ~7 percent of the TN and ~10 percent of TP discharges in the sea. Inappropriate siting of cages has been blamed for the destruction of nearshore and benthic aquatic ecosystems over the past decade; however, recent studies have found that if cages are sited above seagrasses, that seagrass meadows can respond positively to aquaculture discharges with no impacts on benthic biodiversity, raising the possibility that a systems approach for large-scale fish production and environmental improvement is possible.



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