Sulfide as a toxicant in aquatic habitats

The toxic effects of sulphide are best understood in mammals and are generally similar in aquatic organisms. At the physiological level sulphide has 2 major effects on mammals: 1) local inflammation and irritation of moist membranes including the eye and respiratory tract; and, 2) cardiac arrest due to paralysis of the respiratory centres of the brain. The toxicity of sulphide to plants, macroinvertebrates, freshwater fish and marine fish is discussed in detail. It is concluded that the role of sulphide in mass kills of fish, shrimp and other animals in brackishwater earthen ponds, lakes and sea cages should be determined.

An aquasilvifarm in the Philippines

Aquasilviculture can be defined as the integration of aquaculture with mangroves. Details are given of an example of aquasilviculture in the Philippines at Puerto Galera, Mindoro. The farm has 3 series of perimeter ponds stocked with tilapia, although milkfish, mudcrab and shrimp may be caught when entering the ponds incidentally.

Aquaculture provisions of the proposed fishery code

A list is given of the provisions for aquaculture in the Philippine Fishery Code, passed by Congress on its third and final reading on 5 August 1997, under the following headings: 1) Code of practice for aquaculture; 2) Fishpond lease agreements; 3) Fish pens, fish cages, fish traps, etc.; 4) Non-obstruction to navigation and to defined migration paths of fish; 5) Insurance; and, 6) Registration.

The culture of seabass

Seabass (Lates calcarifer) are raised in ponds and cages in Southeast Asia. Details are given of the 2 phases involved in the pond and culture culture systems -- nursery and grow-out. Both monoculture and polyculture systems are used for pond production of seabass. Polyculture may involve milkfish and tilapia, groupers, seaweed, tilapia or snapper, grouper and shrimp.

Aquaculture for whom?

Aquaculture and coastal resources management is discussed, indicating the various factors which need to be taken into consideration when introducing aquaculture into a community: 1) Resources users and stakeholders; 2) Perception about resources; 3) Knowledge about aquaculture; 4) Property rights regimes; 5) Gender matters; 6) Consumer preferences; 7) Availability of support services.

Knowing Asian aquaculture and fisheries. Part 1

An outline is given of aquaculture and fisheries in Asia, providing information of use to students whose work can influence laws, rules, policy and regulations on aquaculture and fisheries, with the view in mind to sustainable aquaculture. In this issue, the following countries are examined: China, Indonesia, and Bangladesh.

Knowing Asian aquaculture and fisheries

An outline is given of aquaculture practices in Malaysia, Philippines and Thailand, which included freshwater, brackishwater and marine systems.

Economic value of the milkfish industry

A brief description is given of the milkfish (Chanos chanos) farming industry in the Philippines. Over the past 20 years, the relative importance of milkfish has declined with the expansion of tilapia, tiger shrimp and seaweed farming. In 1975, some 141,461 mt of milkfish made up 10% of the total fish production, whereas in 1995, the total milkfish harvest of 150,858 mt made up only 5.5% of the total fish production. Milkfish are harvested and marketed mostly fresh or chilled, whole or deboned, but some are canned or smoked. The domestic markets, mainly in Metro Manila, absorb most of the production. Milkfish is also absorbed in different product forms: dried, canned, smoked, or marinated. An export market for quick-frozen deboned milkfish fillets has begun to develop and fish processing companies are responding fast. The milkfish farming industry has important linkages with the various sectors that supply the inputs, and those that transport, store, market or process the harvest. For intensive milkfish farming to be both profitable and sustainable, more value-added products must be developed and marketed.