present and potentially renewable fish stocks: in this context a better quantification of the long term biologi­cal and economic benefits of selective fishing could con­vince the actors of its importance and urgency;
•     Devise new fishing techniques that are highly selective with a minimum impact on the ecosystem in coastal and high sea fisheries and/or that have a smaller ecological effect on the habitats that sustain the fisheries; and
•     Improve existing fishing technologies: to obtain a higher quality of fished products while simultaneously mini­mizing by-catch.

Fish processing for food:
•     Focus on processing and adding value to small pelagic fishes for human consumption, usually fished to make fish food and animal foods (yearly around 18 million tonnes in the world); and •     Improve processing methods and quality of the existing processing units or build new processing units that have the least environmental impact feasible.

6.2.9.2 Aquaculture
Developing countries such as China, others in South East Asia and some CEC countries will continue to expand pro­duction of low-valued fish, such as carp, and will greatly expand production of some high-valued fish, such as shrimp and salmonids (Delgado et al., 2003). The NAE region will continue relatively constant production of high-valued fish, such as salmonids. Trade in aquaculture is likely to increase or at least stay the same and perhaps South-South trade will increase. However, with increasing affluence in some devel­oping countries, this trade dynamic is likely to change with a reduction in trade due to increased home consumption. Some of the main areas with identified research gaps are listed below.

Disease and water quality. An important aspect of aquacul­ture is combating viruses, bacterial and parasitic diseases. It is however difficult to guarantee a strict sanitary isolation of aquaculture sites. Therapeutic options are limited and often lead to environmental problems. Research on the fish immune system can provide more therapeutic options and allow an understanding of the environmental determinants of immunity. These are necessary prerequisites for the sus­tainable use of genetic resources for disease resistance.
     The aquatic environment is subjected to pollution from both human activities  (accumulation of pollutants: e.g., heavy metals, pesticides), nature (e.g., heavy metals and acids from volcanoes) as well as aquatic microorganisms (toxin production by microalgae). More research on eco-toxicology and ecopathology will provide a better under­standing of these impacts on fish quality and production. It would be advantageous if such research were done in close collaboration with research in physical sciences (hydrody­namics, modeling of the pollutant flux, etc.). Also research to improve the quality of the aquatic environment could be done, through the optimization of physicochemical and mi­crobiological quality of the aquatic environment.

Environmental impacts of aquaculture. Aquaculture can have negative impacts on the environment (SOFIA, 2006).

Firstly, aquaculture activities in general can perturb and alter the surrounding environment. Secondly, wastes from intensive aquaculture often have adverse effects on the en­vironment. Thirdly, escaped fish can destabilize nearby na­tive fish communities. The impact of the wastes of intensive aquaculture is due, primarily, to the quality and the quan­tity of fish diet (concentrated fish feed). Some of the ways to combat this is are, for example, to (1) increase the effi­ciency of fish feed to reduce the quantity of the overall diet; (2) substitute fish meals that are classically made of fish oil and fish meal with plant products and (3) in closed systems, develop biofilters using biofilms that recycle wastes back to fish feed. Aquaculture can have positive effects on the en­vironment by reducing the pressures on native fisheries, as well as increasing the fertility of the water though wastes.

Reduce dependence of high value fish farming on fish meal derived from coastal capture fisheries. To reduce impacts on fisheries, fish meal made from plant products might be substituted for fish meals that are classically made of fish oil derived from coastal capture fisheries. One of the areas of research that might reduce dependence on coastal fisheries is to produce feed crops with high levels of oils and proteins required in aquaculture.
     Labeling or certification for responsible fish farming: Aquaculture's future is determined not only by the market price but also by consumers' acceptance of its products. Aquaculture may find it useful to expand linkages of its im­pact (or lack thereof) on the environment with the type of products produced and production practices with market­ing. Initiatives that integrate these aspects have already been adopted in certain areas (the global aquaculture alliance— created by shrimp farm producers—which proposes a code of good practices that would help in reducing the environ­mental impacts of their activities; organic aquaculture; labels certifying the quality like red label, etc.) but more research is necessary to define appropriate management strategies and establish the relevant criteria that would help in the evalua­tion of the efficiency of these strategies and lead to an even­tual labeling or certification of the product.
     Moderate intensification of extensive systems: Intensi­fication of aquaculture seems inevitable due to increasing reduction in the area available for these activities (SOFIA, 2006). The most desired solution may be to opt for moder­ate intensification of current extensive aquaculture systems (often polyculture  systems comprising different species). This transition can only be successful following more re­search on:
•     Identifying optimum conditions for the different types of polyculture systems as the different species involved in polyculture systems have different ecological roles;
•     The criteria for the amelioration of environmental im­pact of a multi-specific population under trophic con­straints (e.g., increase in the growth rate, nutritional behavior). Amelioration of the impact of one species in a polyculture could be done to the detriment of others and may not result in the overall amelioration of im­pacts; and
•     Better understanding of the integration of these systems in rural areas: eventual constraints (e.g., water manage­ment), opportunities, complementarities (e.g., use of ag-