Philippine Mangroves have decreased from around 500,000 ha at the turn of the century to 132,000 ha in 1990. Given the varied and important socioeconomic and ecological functions of mangroves including harvest of forestry and fishery products, coastal protection, erosion control and pollution abatement, there is a need to rehabilitate degraded areas. Half of the mangrove areas lost in the las three decades can be traced to the construction of 141'000 ha of brackish water ponds monocropped to mik fish or shrimp. Integrated aquasilviculture is an alternative, although experimental, technology that combines both the fisheries and forestry functions of the mangrove ecosystem.This paper describes four models of mangrove rehabilitation and conservation with varying degrees of community participation in the philippines-monoculture mangrove planting in Kalibo, Aklan; mixed species planting in Silay City, Negros Occidental; aquasilviculture in Puerto Galera, Mindoro Oriental (family) and in Hinobaan, Negros Occidental (association)- and compares their strengths, weaknesses, opportunities and threats.

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.

Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enriched fish by catch (TFC), and commercial HUFA A-enriched fish by catch (TFS) was monitored. Monthly egg production, spawning frequency, fertilization rate, egg viability, and hatching rates of the control were significantly higher compared to TFS Egg production. Spawning frequency and hatching rate of TC and TFS were not significantly different. Results suggest that varying the species of fish by catch could provide the requirements of E. Coioides broodstock so as to provide quality eggs.

Initial work on seed production of grouper in the Philippines was first reported in 1986. Most of the work has been undertaken by the SEAFDEC Aquaculture Department (SEAFDEC/AQD), which concentrated on Epinephelus coioides. The achievements and results of SEAFDEC/AQD on breeding and larval rearing of grouper which including studies on sex inversion will be discussed. Directions for future research directions are also presented.

Research in seaweed from 1988–1994 focused on the agar producing Gracilaria. Studies in the following areas were also conducted: inventory of the seaweed resources; production ecology; farming systems; and agar characterisation. Six species of Gracilaria and one Gracilariopsis abound in the Western Visayas. There were monthly variations in biomass and agar quality of G. blodgettii, G. manilaensis and G. heteroclada collected at different places. The bulk of the studies were carried out on Gracilariopsis heteroclada because of its wide distribution, fast growth characteristics and good quality agar. Its reproductive state was seasonal with tetrasporophyte abundant in May and carposporophyte in January. Seventy-five percent harvesting of the available biomass was sufficient for the next cropping season. Harvesting the seaweed using “araña” was not appropriate in places where the biomass was exposed to air during the lowest tide. The addition of nutrients to the stock increased the growth rate of the seaweed and gel strength of the agar. G. heteroclada grown at lower stocking density in hapa nets, both in floating cages and in ponds, gave higher growth rates and production than at higher stocking densities. This species, when polycultured with P. monodon at lower stocking density combinations, gave the highest growth rate and income. Likewise, this species when cultured vertically in ropes inside a floating cage showed encouraging results. G. heteroclada, when grown at 24–25 ppt under tank conditions, produced the highest gel strength.

Wild-caught mangrove red snapper (Lutjanus argentimaculatus) were reared in a floating net cage at SEAFDEC/AQD's Igang Marine Substation at Guimaras Island, Central Philippines. In 1993, monthly samplings and induced spawning trials were conducted as part of a project on seed production. Gonadal development began in February for males and April for females, reached a peak in September and declined in December. Males and females had ripe gonads for up to 5-6 consecutive months. Spawning occurred in the evening (2000 to 2300 hours), 32-36 hours after a single intramuscular injection of 1,500 IU human chorionic gonadotropin kg^-1 body weight (BW). About 0.53-2.14 million eggs were collected per female (2.5-4.4 kg BW) with fertilization rates of 21-97% and hatching rates of 42-80% resulting in 30-85% normal larvae (straight and without deformities). The results strongly suggest the feasibility of breeding mangrove red snapper in floating net cages.

Sixteen isolates of Aeromonas hydrophila andone isolate each of Aeromonas sp. n., Aquaspirillum sp., Pseudomonas sp., and Streptococcus sp., isolated from normal, apparently normal and epizootic ulcerative syndrome (EUS)-affected fish were screened for siderophore production at 20, 25, 30, and 37^oC. results showed that siderophore production of A. hydrophila and Aeromonas sp. n. isolates decreased with increasing temperature. Among A. hydrophila isolates, 81.2% produced siderophore at 20^oC, 50% at 25 and 30^oC, and only 37.5 at 37^oC. In contrast, Aquaspirillum sp., Pseudomonas ep., and Streptococcus sp., showed higher production of siderophore at 30 and 37^oC.

In the past 5 Yr, bacterial diseases have become limiting factors in penaeid culture systems, their effects becoming directly proportional to the growth of the industry in terms of severity and imoact. Although eight bacterial genera have been associated with these problems, only two groups accur quit commonly: filamentous bacteria and vibrios, with the latter beibg more impact. Many Vibrio species have been reported in penaeids: Vibrio alginolyticus, V.cholerae (non-01), V. damsela, V. fluvilis, V.nereis, V. splendidus, V. tubiashii, V. vulnificus, V. parahaemolyticus, and V. harveyi. Interestingly, the last three species, all non-sucrosefermenters, are the most dominat. Diagnosis has beed done mostly through conventional bacteriology and histopathology, although development and use of more rapid detection methods like indirect fluorescent antibody technique, monoclonal antibodies, and other enzyme immunoassays are in demand to improve monitoring and survellance. Because of the conflict between the use of chemotherapeutants and the evironmental hazards that go with it, many researches are now poised on non-medicinal approches to solve bacterial diseases problems.