Aquaculture and Fisheries News => Aquaculture News => ข้อความที่เริ่มโดย: Nicaonline ที่ พฤศจิกายน 11, 2006, 01:04:26 PM

หัวข้อ: The Philippine Shrimp Farming Industry On the Road to Recovery
เริ่มหัวข้อโดย: Nicaonline ที่ พฤศจิกายน 11, 2006, 01:04:26 PM

Philip S. Cruz, a member of the Philippine Fisheries and Aquaculture Board and owner of Cruz Aquaculture Corporation, which does consulting and is involved in the hatchery and growout of shrimp, crayfish and some marine fish, reports:

After becoming the world's leading producer of giant tiger shrimp (Penaeus monodon) in 1984 and after producing 90,426 metric tons a decade later, the Philippine shrimp farming industry collapsed in 1997. Production dropped to 40,080 metric tons due to widespread disease and pollution problems. Most severely affected were the high-density farms on the islands of Negros, Cebu and Mindanao (around the cities of Davao and General Santos). Ever since, annual production has remained at 35,000–40,000 metric tons with the bulk of the harvest coming from extensive farms. A virulent strain of luminous Vibrio caused most of the disease problems. A recent study by SEAFDEC-AQD on the molecular characteristics of local Vibrio strains suggests that V. harveyi and V. campbellii were the primary culprits. Just as farmers succeeded in managing luminous Vibrio, whitespot hit in 2002, further delaying a recovery.

Over the last several years, however, shrimp farming has made a comeback because of major modifications in our management practices. Among the key modifications:

Crusticides to remove WSSV carriers
Multiple PCR screenings of postlarvae
Probiotics in hatcheries
Increased aeration on farms
Increased use of dietary immunostimulants
Reduced water exchange
Adoption of stringent farm biosecurity measures
Use of tilapia/greenwater technology

In 1994-1995, shrimp farmers on the island of Negros discovered that filling their ponds with "greenwater", the algae-rich effluent from a reservoir stocked with tilapia, inhibited the luminous bacteria disease. They stocked their reservoir ponds with all-male tilapia at a biomass of around 1-2 metric tons per hectare. Some farmers also culture all-male tilapia in cages within the growout ponds at a standing biomass of around 300 kilograms per hectare in combination with the tilapia effluent from the reservoir. Tilapia effluent is dominated by Chlorella algae, which has been found to inhibit Vibrio growth. Chlorella also inhibits the growth of blue-green algae, resulting in improved and more stable water quality.

Shrimp farmers have learned a lot from neighboring countries, especially Thailand, through Charoen Pokphand/Philippines, a producer of shrimp feeds. During the second quarter of 2006, a sharp unexpected rise in the incidence of WSSV hatchery-bred fry on Negros Island was successfully controlled by farmers through the use of a new aquaculture disinfectant (Virkon®, manufactured by DuPont), based on experiences of shrimp growers from Vietnam. All these new management strategies put together, coupled with years of experience, have now made production more predictable and risks more manageable.

By 2004, both luminous vibriosis and whitespot disease were declared "manageable" and this has since led to a revival of the industry on Negros. From March 2004 to March 2005, some 203 hectares of growout ponds monitored by the Negros Prawn Producers' Marketing Cooperative, Inc., yielded 950 metric tons of giant tiger shrimp, from an average stocking density of 20.6 PLs per square meter. Harvest size averaged 32.7 grams, with a culture period of 130 days and a feed conversion ratio of 1.83. In 2006, Negros farmers aim to increase harvest size to 35-40 grams.

At the 5th National Shrimp Congress (June 2006), the Philippine shrimp industry, one of the world's last monodon "loyalist", endorsed the farming of the nonnative western white shrimp (P. vannamei). The three-year debate over vannamei caused deep divisions within the industry. A major factor that led to a favorable decision on vannamei was a steep rise in production costs for P. monodon and the scarcity of good quality monodon spawners, which delayed the stocking of farms. Having essentially started the monodon revolution in 1975 by opening up the Japanese market, the Philippine shrimp industry's use of monodon is understandable. It is interesting to note, however, that the first vannamei growout trials in Asia probably happened here way back in 1978-79, from a one-time importation of undomesticated stocks that performed pitifully compared to monodon.

At present, controlled introduction of vannamei in selected demonstration farms on the island of Luzon by the Bureau of Fisheries and Aquatic Resources have yielded impressive yields and attractive production costs, paving the way for the expected full lifting of the ban on vannamei before the end of 2006, giving farmers a free choice on which species to culture. Based on the study by the Fisheries and Aquaculture Board of the Philippines, the Philippines has the potential to produce at least 100,000 metric tons of vannamei in the next five years, on top of the current monodon production.

With the predominantly low farmgate prices for monodon in recent months, most of the intensive monodon farmers have reduced stocking densities to around 15 PLs/m2 and hope to harvest 35-gram animals. Field reports gathered to date suggest that this target will likely be achieved. For 2006, Philippine shrimp production is projected at around 40,000 metric tons, of which some 90% will be monodon, 4-6% vannamei and the balance consisting of local shrimp species.

On November 4, 2006, Cruz emailed: "There is still no final word on the lifting of the ban on vannamei, partly because we changed agriculture secretaries just a few weeks ago. I am still optimistic that the ban will be lifted before the end of the year. The 'experimental vannamei ponds' on Luzon continue to expand with an aggregate area already in excess of 200 hectares."

Information: Philip S. Cruz, Cruz Aquaculture Corporation, 158-C Araneta Street, Singcang, 6100 Bacolod City, Philippines (email, webpage

Source: 1. Emails to Shrimp News from Philip Cruz. Subject: Re: From Shrimp News. September 10 and 22, 2006. 2. The CD of the Aqua 2006 Abstracts (World Aquaculture Society, Florence, Italy, May 2006). Coping with Luminous Vibriosis and White Spot Disease in Black Tiger Shrimp: The Negros Island Experience. Philip S. Cruz. 3. Email from Philip Cruz on November 4, 2006.