By: In-kwon Jang, Hui Gong
Located in the Northern part of the African Continent, Algeria, the second largest African country, is famous for its Sahara desert and abundant resources of oil and gas production. Although shrimp aquaculture is not an ordinary activity naturally associated with the desert, Algeria proves its capability of using underground water to produce Penaeus vanamei, the whiteleg shrimp which is originally from the Pacific Ocean.
The Sahara Golden Shrimp production is housed at the Ouargla Shrimp Cultivation Research Center, an Official Development Assistance project funded by the Korea International Cooperation Agency (KOICA), with a total investment of US $6 million.
On January 26, 2016, a tasting demonstration from the first successful harvest of 500kg of shrimp with an average weight of 23g after a 110 day grow-out period, became a sensation when the news was broadcast on both Algerian and Korean TV stations and distributed through news media outlets.
The facility is in Ouargla which is in the middle of the Sahara desert, about 800 km from the Mediterranean coast. The construction of the facility was initiated in 2011, and some preliminary bioassay trials in a facility nearby had been conducted 3 years prior. Operations have been ongoing for one and half years, with an estimated production of 100 tons from an outdoor demonstration farm this year. Dr. In-kwon Jang, the project manager and his team from the National Institute of Fisheries Science, Republic of Korea, are responsible for transferring bio-floc technology and providing technical support. Encouraged by this recent demonstration farm success, the Algerian government plans to develop more extension farms in oasis areas in five adjacent states, and aims to produce 2000 tons of shrimp by 2020.
Prior to the Sahara project, there had been tremendous efforts and preparatory work in shrimp research in the region and these should also be credited for the recent successes. For example, the same Korean research team had completed the first shrimp project in Skikda, on the eastern coast of Algeria, to successfully produce Penaeus japonicus postlarvae from hatchery facilities and subadults from a grow-out farm from 2008 to 2011. In addition, the Korean research team was also responsible for producing several millions of Penaeus kerathurus postlarvae, the indigenous species, for restocking in the Mediterranean Sea.
Nevertheless, the Sahara project encountered various challenges as the operation moved forward. To help the readers catch a glimpse of the complex culture issues, some detailed information for the Sahara operation are provided as below.
Water used for rearing the shrimp is the local underground well water with a salinity of 2 ~ 4 ppt drawn from a depth of approximately 100 meters. Apart from the salinity difference, the ionic composition and ratios in the underground water are totally different from those in seawater, especially Mg2+/Ca2+, Na+/K+, and K+/Cl-. These differences posed strong energetic, metabolic and physiological challenges for shrimp to maintain proper osmo-regulatory functions. Many trials/attempts had been carried out to correct the water mineral imbalance issue. Extreme ambient temperatures and dry climate make the control of water temperature within a desirable range a great challenge. Daily variation of temperature and seasonal changes are usually huge, with differences reaching up to 25°C.
Shrimp seedstock and acclimation
The 1st batch of P. vannamei postlarvae was imported from Shrimp Improvement Systems in Florida, United States in September 2015. With five airport stops, the shipment lasted 45 hours in total transit, which resulted in the survival rate between 70% and 80% upon its arrival at the Algerian research center. With the rather different ionic composition profile of underground water as compared to the seawater, long distance hauled seawater from the northern Mediterranean Sea proved to be essentially effective in initiating the salinity acclimation for the shrimp postlarvae received and for microalgae culture. After the salinity acclimation process, nursery culture started with a stocking density of 10267/m2 and lasted three weeks in October, yielding a survival rate of over 97% as the shrimp were growing to 0.079g from the initial weight of 3.8mg.
Upon completion of the acclimation process, a biofloc recirculation system was used for the shrimp growout. The stocking density was between 150 to 300 / m2, which yielded a harvest of 500kg on January 16, 2016 with harvest shrimp size of 23 grams.
The facility includes both indoor and outdoor systems. Indoor facilities consist of three raceways (80 m2 each) and three circular tanks (25 m2) with well established aeration and piping systems to foster uniform and consistent biofloc for shrimp culture. Lined with HDPE material, the outdoor tanks are 0.1 ha, 0.2 ha, or 0.5 ha, and there are four tanks in each size category. To avoid extremely high temperatures during the summer, when the mid-day ambient temperature can reach up to 60°C under direct sunlight, the 1st harvest is programmed to be completed by July, while the 2nd stocking should take place in September and be harvested in November.
The research building is comprised of several laboratories, such as a water quality lab, a pathology room, a laboratory microscope chamber in order to perform routine water analysis, ion chromatography, and diagnosis for shrimp bacterial and viral diseases on site.
Exploring this new live penaeid species for aquaculture under extreme environmental condition, the success story of the Sahara Golden Shrimp project not only infuses the barren desert with great potential for shrimp business opportunities, but also makes a strong statement concerning what the combination of science, technology transfer and aid programs can do for a mission “impossible.”
In-kwon Jang is Project Manager of Sahara Shrimp Farming Project of Algeria, NIFS/KOICA, Republic of Korea. He can be reached at email@example.com
Hui Gong, PhD, is an Associate Professor at the College of Natural and Applied Sciences at the University of Guam. Her expertise in shrimp aquaculture has built on 17 years of experience in applied research in both academic and industrial backgrounds.