The modular method: Milkfish pond culture

The modular method of milkfish culture (Chanos chanos) described in the manual is an improvement over the traditional extensive method. The manual is intended for the use of fish farmers and aquaculturists, extensionists, and students of aquaculture not only in the Philippines, but also in other milkfish-producing countries in Southeast Asia and the world. It covers the following: Interesting facts about milkfish -- biological characteristics, artificial breeding of milkfish; Design and operation of modular pond system -- pond preparation, stocking in the nursery or transition ponds, stocking in the rearing ponds, care of stock, pond utilization and production schedule, harvest and post-harvest; and, Economics and costing

Stock assessment of commercially important fishes in Naujan Lake

The study aimed to assess the capture fisheries of Naujan Lake with emphasis on commercially important fish species and to determine the extent of their exploitation. Four major fish landing centers in the municipalities of Socorro, Pola, Victoria and Naujan were surveyed from May 1995 to December 1996. Eight types of fishing gear had been recorded. The most commonly used was gill net or 'pante', followed by fish pot 'bubo', fish corral 'baklad', spear 'salapang', spear gun 'pana', fish trap 'patanga', encircling net 'takilis' and long line 'kitay'. Tilapia comprised 61% of the total fish production of the lake, followed by therapon (16%), goby (4%) and mudfish (2%). The other species caught were 'pla salid', catfish, mullet, carp, milkfish and shrimp, which contributed 17% to the total production. Migratory fishes like the mullet and milkfish, on the other hand, showed a declining trend in production

Effect of temperature and salinity on the hatching of eggs and larval development of sugpo, Penaeus monodon

Abstract only.Incubation of Penaeus monodon eggs and rearing of different larval stages were undertaken at nine temperature-salinity combinations. The eggs, nauplii, zoea and mysis from one spawner kept as stock culture at ambient temperatures of 26-30°C and salinity of 32-33 ppt were exposed to temperature levels of 23, 28 and 33°C and salinity levels of 23, 28 and 33 ppt. Eggs and nauplii survived the sudden change of temperature and salinity (from ambient to experimental) but the zoea and mysis did not. However, salinities of 23 and 28 ppt in combination with any of the temperature levels produced weak larvae. Highest mean hatching rate was obtained at the temperature-salinity combination of 23°C-33 ppt, followed by 28°C-33 ppt and 33°C-33 ppt. Incubation periods for these treatments were 22, 16 and 14 hr, respectively. Survival rate of nauplius (taken from stock cultures) to first zoeal stage was highest at 28°C-33 ppt, followed by 33°C-33 ppt and 23°C-33 ppt with molting time of 50, 45 and 75 hr, respectively. The nauplii exposed to 33°C-33 ppt molted to zoea stage within 38 to 40 hr but later died. Those exposed to 23°C-33 ppt and 28°C-33 ppt reached zoea stage within 57 to 60 hr and 48 to 50 hr, respectively. Similarly, the nauplii taken from the stock cultures and reared until postlarval stage (P1) under experimental conditions completed the zoea and mysis stages in 9 to 11 days at 28°C C-33 ppt, 7 to 9 days at 33°C-33 ppt, and 13 to 15 days at 23°C-33 ppt. Statistical analysis showed that salinity had highly significant effect on rates of hatching of eggs and survival from nauplius to first zoeal stage but not temperature although the latter had an apparent effect. However, both factors affected time of hatching of eggs and time of molting from nauplius to zoea. Interaction effect was significant only on rate and time of hatching. Different sources (spawners) of eggs and nauplii did not have significant effect on time of hatching and molting from nauplius to zoea, but significantly affected the hatching rate of eggs and survival rate of nauplii to zoea stage

Growth and productivity of juvenile banana prawns, Penaeus merguiensis in natural and laboratory systems

Abstract only.Growth and survival of Penaeus merguiensis juveniles were measured over four years in the Norman River estuary, south-eastern Gulf of Carpentaria. Growth in carapace length for the first 8-9 weeks after settlement was essentially linear and averaged 1.2 mm/week in summer at 29.5°C and 0.45 mm/week in winter at 19.5°C. A comparison of different cohorts under varying temperatures and salinities indicated that growth was temperature- but not salinity-dependent. Survival of newly settled postlarvae varied seasonally and was highest in spring (October-November). In the laboratory, a study of moulting rate and moult increment at 15, 20, 25, 30 and 35°C demonstrated that the optimal temperature for growth was 25-30°C. Survival of juveniles was also highest at intermediate temperatures. Effects of salinity and food ration amounts are discussed

Review of SEAFDEC/AQD fish nutrition and feed development research

Research on fish nutrition and feed development at SEAFDEC Aquaculture Department has focused on three major areas: nutrient requirements and their interrelationships, digestive enzymes and digestibility, and practical feed development for important species such as milkfish (Chanos chanos Forsskal), sea bass (Lates calcarifer), Nile tilapia (Oreochromis niloticus), bighead carp (Aristichthys nobilis), and tiger shrimp (Penaeus monodon). Early studies on the nutrient requirements were mainly on protein, lipid and carbohydrate. Studies on essential amino acids and fatty acids, and optimum proteln:energy ratio in the diets for cultured species were conducted later. Likewise, requirements for other essential nutrients in shrimps, like phospholipid and cholesterol, were studied. Dietary calcium and phosphorus required to prevent soft-shelled shrimps were determined. Requirements for water-soluble vitamins and bioavailability of stable forms of vitamin C were evaluated. Little is known of the vitamin and mineral requirements.The major digestive enzymes in milkfish have been studied. The apparent digestibility of common feedstuffs were determined in vivo and in vitro for milkfish and tiger shrimp, and presently, for sea bass. Development of cost-effective practical feed continues to be a major research undertaking at SEAFDEC/AQD. Diet refinement emphasizes on use of inexpensive and indigenous materials in diet formulations. The feasibility of using legumes, leaf meals, and agricultural by-products and wastes as feed components has been demonstrated. Feed and feedstuff quality control and proper processing techniques were found to improve the nutritional value of low-grade raw materials. Improved feeding techniques and practices have been pursued to minimize feeding costs. Studies on the effect of feeds on the environment are being initiated. Economically feasible grow-out diets for semi-intensive culture of milkfish, Nile tilapia, and tiger shrimp, and diets for broodstock and larvae of these species have been developed

Grouper culture in floating net cages

The manual describes the culture of groupers (Epinephelus) in floating cages, providing a farming option for grouper growers and also a production alternative to the farmed species being done today, such as shrimp, milkfish and tilapia. The following aspects are covered: species identification for commercially cultured groupers; source of stock; net cage specifications; anchor; hides and shelters; nursery net cage operation; production cages; harvesting; post-harvest; profitability analysis of grouper cage culture; and, cost and return of growing grouper in cages

Marine shrimp culture industry of Thailand: operating guidelines for shrimp farms.

The marine shrimp industry in Thailand had developed a code of conduct for its operations. This code of conduct is a set of principles and processes that provides a framework to meet the industry’s goal for environmental, social, and economic responsibility. The foundation of the code of conduct is the following mission statement. The marine shrimp farming industry in Thailand is committed to producing high quality, hygienic products in a sustainable manner that provides for environmental, social, and economic benefits for the present and future generations. Policy statements have been formulated to outline actions that the industry will undertake to meet its commitments under the mission statement. These policy statements cover a broad range of topics, including: environmental protection, public consultation, regulatory compliance, location, quality and safety, continual improvement, efficiency, research and development, social responsibility, monitoring and auditing, education and training, international trade. The code of conduct is voluntary, but it has been signed by a wide variety of industry stakeholders. The code commits the signatories to specific actions, including the development of a series of operating guidelines and procedural manuals. These actions will aid the industry in carrying out its operations in a manner consistent with the objectives of the code of conduct

Verification of semi-intensive shrimp culture techniques: Vietnam.

Vietnam has about 260,000 ha devoted for shrimp culture in early 1999. The total production was estimated at about 80,000 tons in 2000, so that productivity was about 300 kg/ha only. In 1990–1997, vast areas of mangroves were destroyed by many fish farmers for conversion into shrimp culture ponds. The Vietnam Government and local authorities have been trying to mobilize and educate farmers for them to refrain from destroying mangroves for shrimp culture; and at the same time promote increased shrimp productivity/ha in order to increase profit; and generate employment without necessarily destroying the mangroves. Cathai is an island district in north Vietnam with 12 communes in two islands, Catba and Cathai. Phulong Island in Catba Island, has the largest mangrove area. Before 1990, the total mangrove area of Phulong was about 2000 ha but in 1998 only about 1200 ha remained, because about 800 ha had been converted into shrimp ponds. However, due to lack of technology in shrimp culture especially the semi–intensive pond culture, production ranged from 200 to 300 kg/ha/crop, while in extensive ponds, production was only 50–70 kg/ha/year. Local authorities and the people of Phulong have been expecting to increase productivity from shrimp culture. Using the mangrove-friendly shrimp technology modeled by the Philippines and Thailand, the objective of the semi–intensive shrimp pond culture activity in Vietnam is to obtain 1000–1500kg/ha and to develop a model for an improved shrimp culture system. In the Memorandum of Agreement signed between the Ministry of Fisheries and the Southeast Asian Fisheries Development Center for the implementation of the Project in Vietnam, the Research Institute for Marine Products (RIMP) in Haiphong was chosen to carry out the demonstration activity focusing on the semi–intensive mangrove-friendly shrimp culture in Phulong, Cathai District, Haiphong, Vietnam. The ponds used for the Project had a total area of about 6.0 ha. Construction of the pond facilities following the Project’s scheme was completed in December 1999