The Current Status (2014) of the Shrimp Farming Industry
Shrimp News: The March 2015 edition of World Aquaculture, the quarterly magazine of the World Aquaculture Society, contains an excellent article by several Vietnamese researchers (see Source below) on the history and current status of shrimp farming in Vietnam. Here I report on the current status. You can view the history report at A Brief History of Shrimp Farming in Vietnam.
The Current Status of Hatcheries
Giant tiger shrimp (Penaeus monodon) seed production is concentrated in the Mekong Delta at small-scale hatcheries. Pacific white shrimp (P. vannamei) seed production is concentrated in the central provinces at large hatcheries. Larval rearing tanks range in size from 48 to 2,800 cubic meters for giant tiger shrimp and 60 to 6,500 cubic meters for Pacific white shrimp.
Giant tiger shrimp broodstock are mostly large, wild-caught animals (250-350 grams). Pacific white shrimp broodstock are mostly imported from other countries (USA, Thailand and Singapore). Recently, trials on the domestication of Pacific white shrimp broodstock have been started at research institutes and private hatcheries.
For larval rearing, two major techniques have been applied: open clearwater systems and recirculating systems. Open clearwater systems are used mainly in large hatcheries near the coast, where there’s an abundance of seawater. Recirculating systems, developed by Can Tho University, are used in hatcheries around Can Tho City, located in the Mekong Delta about 60 kilometers from the sea. Brine from salt evaporation ponds is used to increased the salinity at these hatcheries.
At giant tiger hatcheries, nauplii are stocked 100-250 per liter of water and the survival rate to the postlarval stage is 50-70 percent. For Pacific white shrimp, the stocking density is 150-300 nauplii per liter and the survival rate is 40-60 percent. Diatoms are used to feed Pacific white shrimp larvae. Because most of the Pacific white shrimp hatcheries are large scale, average annual production is 47 to 1,780 million postlarvae per hatchery, which is much greater than that of the small-scale giant tiger hatcheries that have average production of 39-172 million postlarvae.
Current Status of Shrimp Farming Technology
Developed in the 1980s, two traditional shrimp farming systems dominate production in the Mekong Delta: integrated mangrove farming and improved extensive farming. Mangrove farming systems are located in the buffer zone, behind the full protection of the coastline. The improved extensive systems are located in the economic zone, farther inland than the coastal buffer zone. Both systems are characterized by large ponds (3-10 hectares), consisting of a raised platform in the center of the pond (a shallow water area that takes up to 60-80 percent of the total pond area), a ditch around the platform, which takes up 20-40 percent of the total pond area and surrounding dikes. With the integrated mangrove systems, mostly Rhizophora mangrove trees are planted on about 50-70 percent of the platform area.
On improved extensive shrimp farms, aquatic plants (Scirpus littoralis and Typha species), seaweeds (Enteromorpha, Chaetomorpha, Cladophora, and Gracilaria) or mangrove trees are planted or allowed to develop naturally on the platform. These plants are good for the environment and create excellent habitat for shrimp, fish and especially mud crabs. In these systems, wild shrimp, fish and crabs flow into the ponds through tidal water exchange during the full moon and new moon. In addition, hatchery-reared giant tiger shrimp postlarvae are stocked at two to four per square meter, two to eight times a year, through two seasons (December-April and June-November). Mud crabs, blood cockles (Anadara granosa) and some brackishwater fish are also stocked at low density to make use of natural food and for diversification of products and income. Almost no supplemental feed is used in these systems.
Two to three months after stocking, shrimp are partially harvested on every new moon and full moon as the pond water flows through a net on an outgoing tide. Annual shrimp production is about 300-400 kilograms per hectare. Large giant tiger shrimp (over 50 grams each) account for 50-70 percent of the harvest. The rest are other wild shrimp like banana shrimp (P. merguiensis), Indian shrimp (P. indicus) and sand shrimp (Metapenaeus ensis). Mud crabs are also regularly harvested from these ponds.
Recently over 6,000 hectares of integrated mangrove/shrimp farming systems have been certified as organic by Naturland. With simple techniques, low capital investment, environmental friendliness, regular harvests, little disease and few economic risks, integrated mangrove ponds occupy 50,000 hectares, while the improved extensive shrimp farming system occupies 330,000 hectares. Further improvements in farming technology are needed for these systems to achieve better shrimp survival rates, production and income.
Systems that rotate rice and shrimp production are very typical in the Mekong Delta and currently occupy more than 160,000 hectares. In these systems, giant tiger shrimp are cultured in the dry season with brackish water, and rice is cultivated during the rainy season with fresh water. Traditional systems are surrounded by a deep ditch on the inside of the pond along the dike and have shallow water levels (30 cm) on the platform. Improved systems are prepared by machines, and have a deeper water (70-80 cm) over the platform.
Stocking densities, feeding and water management of the two systems differ. In the traditional systems, shrimp are stocked at low densities (2 to 5 shrimp per square meter), feeding is intermittent and management is simple. Shrimp yields of 200-300 kilograms per hectare per crop are normal. In improved systems, shrimp are stocked at higher densities (6 to 8 shrimp per square meter), fed commercial feeds and water quality is carefully managed. These ponds yield 800-1,500 kilograms per hectare crop.
In the shrimp/rice rotation systems, the 3-4 month shrimp crop is cultured in the dry season and a traditional variety of rice is planted during the rainy season. Due to enhanced soil fertility after the shrimp crop, very limited or no fertilizer is used for rice cultivation. Rice production can reach 3 to 5 tons per hectare per crop. Giant freshwater prawns (Macrobrachium rosenbergii) are also normally stocked during rice cultivation at low stocking densities (1 to 2 prawns per square meter) with some feeding. Prawn production is about 50-100 kg/ha/crop.
Intensive farming of giant tiger shrimp and Pacific white shrimp developed in the central provinces. Today, however, the Mekong Delta has more intensive ponds than the central provinces. Recently, the majority of intensive shrimp farms shifted from farming the giant tiger shrimp to Pacific white shrimp because of the white shrimp’s advantages of rapid growth, high production and low risk of diseases.
Generally intensive shrimp ponds are rather small (0.2-0.5 hectares) and may be lined for Pacific white shrimp culture. Stocking densities are greater for Pacific white shrimp (70-150 per square meter) compared to giant tiger shrimp (20-35 per square meter). Pacific white shrimp culture with biofloc technology uses even greater stocking densities, requires a greater investment and is implemented mainly in the central provinces. With intensive culture, water exchange is limited and probiotics are commonly used for water management and health management. Pacific white shrimp are harvested after 90-100 days, yielding 10-15 metric tons per hectare per crop. Giant tiger shrimp are harvested after 100-150 days, yielding 3-7 tons per hectare per crop. The survival rate of shrimp is currently rather high, although the industry has also been faced with serious disease problems (early mortality syndrome, whitespot and other diseases) for several years.
Intensive shrimp farms might be mom-and-pop operations, cooperatives, individual entrepreneurs or large companies. Each production firm type has different advantages and disadvantages. Many large companies have hatcheries, farms, processing plants and export facilities. These companies often hold international certifications from Global GAP, Best Aquaculture Practices or the Aquaculture Stewardship Council.
In conclusion, through several decades of development, shrimp seed production and farming have become increasingly important activities and play important roles in the socioeconomics of the coastal areas of Vietnam, in general, and the Mekong Delta, in particular. Although shrimp farming is intensifying, large areas of improved extensive farming systems, integrated farming systems and roating rice/shrimp farming systems continue to be maintained for sustainable development. Certification for shrimp farming with national and international standards is an important target in the near future. The shrimp industry is on the move toward sustainable development and meeting planned targets of 630,000 hectares and 700,000 metric tons by the year 2020.
Source: World Aquaculture (the quarterly magazine of the World Aquaculture Society). Editor-in-Chief, John Hargreaves. Innovation in Seed Production and Farming of Marine Shrimp in Vietnam. Tran Ngoc Hai (email email@example.com), Pham Minh Duc, Vo Nam Son, Truong Hoang Minh and Nguyen Thanh Phuong. Volume 46, Number 1, Page 32, March 2015.