5.1 Biological Standards
5.2 Environmental Standards
5.3 Socio-Economic Standards
Monitoring and evaluation of sea farming and sea ranching depend on agreed standards and criteria, which involve biological, environmental and economic factors. In the long term, sea ranching, natural resources enhancement and mangrove reforestation should be considered as priorities, but financing aspects are critical.
Primary productivity in a given water can be considered as a constant. It has been estimated that the oceans contain 20 to 31 milliard tons of organic carbon which could be converted into aquatic products. In the absence of farming and ranching activities, capture fisheries depend on natural species composition. From an economic point of view, the existing organic carbon could be converted into aquatic species with a high or a low commercial value. Herbivorous species such as abalone and filtering animals such as oyster, scallop and clams, situated at the second level of the food pyramid, are very efficient in converting organic carbon into aquatic products. On the contrary, carnivorous species, situated at a higher level of the food pyramid, require 10 to 40 times more organic carbon to produce the same amount of seafood. Therefore, it sounds rational to give priority to species of the first group and to increase their production, in particular for species with a high commercial value.
There is no doubt that carnivorous species such as groupers, perches, breams, flatfish and salmonids, are the main farmed species. In the near future, these finfish should become major mariculture species. The problem is how to farm or ranch them. Under the present situation, sea farming and sea ranching are rapidly developing and produce an ever greater proportion of the fishery production.
Concerning the introduction of exotic species, China has chosen to rationally introduce those species which would increase the commercial value of existing stocks. From the 1950s and particularly since the 1980s, several exotic species have been introduced for farming and enhancement, including finfish, molluscs, crustaceans and seaweed. Such introductions are strictly forbidden in some countries. At present, these species benefit farmers and fishermen, but it is difficult to predict what will happen in the future.
In the past, aquaculture has been considered as a clean industry, even if this has depended on farmed species and cultural system. For example, kelp farming (Figure 29) not only does not create any pollution but it purifies the environment. On the contrary, inshore cage culture is a source of pollutants, especially if trash fish is used for feeding (Figure 30). Therefore, protecting the aquatic environment is the lifeline for the aquaculture industry.
In order to protect the aquatic environment, regulations are necessary to control the following sea farming and sea ranching aspects:
- Rational distribution of aquaculture sites
- Development of offshore cage culture to replace inshore cages
- Interdiction to use trash fish for feeding farmed fish
- Culture of carnivorous species in association with either autotrophic or filtering species.
Figure 29. Kelp farming in a shallow sea
(a) Farmers harvest the floating kelp
(b) Harvested kelp is transported to the processing site
Environmental protection and economic development are clearly related to each other. Nothing can be accomplished without taking into account the latter. But protection and enhancement of the environment are at its base. There is no doubt that a developing economy should pay more attention to environmental protection. A good environment is necessary for the sustainable development of the aquaculture industry. It is believed that in the near future three cultural systems should become most important: offshore cage culture, intensive culture in recirculation facilities and sea ranching in improved marine environments.
Figure 30. The use of trash fish for feeding fish in inshore cages
(a) Farmers cut trash fish into small pieces
(b) Trash fish are transported to the floating cages
Sea farming and sea ranching activities are only a small part of the whole socio-economic sector. The objectives of fishery products production are to meet food demand of human beings and to satisfy the psychological pleasure of enjoying seafood. Particularly in a developing country such as China, fishery production should aim at these two objectives by (i) meeting food demand with low production costs for the indigenous population and (ii) supplying seafood markets at higher costs.
All interested parties, policy makers, investors or farmers, should seriously consider socio-economic impacts. They should also address several other priorities such as:
