A strategy for sustainable mariculture

Abstract

From merely growing shellfish and macroalgae along the freinges of the sea, man is naw growing marine fish in cages thus expanding the range of mariculture. While the farming of shellfish may have its own set of problems it is the growing of fish that particularly poses more serious problem. This is especially true since high value fish which invariably are carnivores are the preferred species. Depending on the hydrography of the site, the species culture, culture method, stocking density, feedtype, and husbandry practices marine fish farming has the potential of greatly increasing the organic load of the immediate waters. the use of chemicals such as therapeutants, vitamins, pigments, and anti-foulants futher adds to the pollution. If the rate and manner of development is left to market forces its sustainability may be jeopardized. Areas that are semi-enclosed are often preferred and can rapidly become subject to overcrowding to the extent that its carrying capacity is exceeded. In addition conflicts between growersand other users can arise thus adding a social dimension to the problem. Sustainability of mariculture can be better assured if the development is not haphazard. The concept of zoning and planned development which is now the standard appeoach on land can wery well be applied in the sea. The open waters can be zoned as to type of aquaculture allowable. Beyond zoning, growers can be induced to set up their cages in semi-exposed or even exposed areas where th hydrography is more ideal for growing fish by providing an infrastructure for mariculture. Such infrastructure may consist of nothing more than mooring facilities for deep-watercages and, where necessary, floating breakwaters. With proper spacing of the mooring points, even the density of the cages in an area can be regulated. This will effectively lower start-up cost since growerswill be spared the expense of installing mooring. This will make it possible to broaden the participation to those with limited access to capita such as small-sscale fishers. Users can be charged mooring fees much as ships are charged berthing fees. Service in the form of security may also be provided. this can be complimented by onshor facilities such as a landing area, feed depot, ice plant, cold storage and processing plant. Such an area can be operated like a marine version of an aindusrial park and can aptly be referred to as a mariculture park. This model of mariculture development is being tried in the philippines.