NACA webinar “Status of the use of Artemia cysts in fish/crustacean hatcheries around the world”
The goal of the webinar was to document differences in practices used by fish and crustacean hatcheries in the use of Artemia cysts for the preparation of live feeds. Over time, the practices used by hatcheries in Asia, Europe and Latin America have diverged from the good aquaculture practices for Artemia production recommended by FAO in the 1996 Live Food Manual.
The technical programme (Table 1) included presentations from twelve speakers from around the world, with an introduction from the Director General of NACA, Huang Jie. The webinar was attended by 359 people from 53 countries.
The webinar was facilitated by the International Artemia Aquaculture Consortium (under formation) as a follow up to the recommendations of the recent article Past, present and future scenarios for SDG-aligned brine shrimp Artemia aquaculture in FAO Aquaculture News. It was hosted by the Network of Aquaculture Centres in Asia-Pacific.
The 0.5 mm brine shrimp Artemia nauplii that can be easily hatched out from so-called “dried cysts” (i.e. inactive embryos in late gastrula stage) are used as a suitable substitute for natural live plankton in the feeding of a wide variety of marine and freshwater crustaceans and fishes. Commercial use of Artemia started in the 1960s, initially in Japan with Japanese seabream and kuruma shrimp and soon thereafter in other parts of the world with many more species. With the expansion of hatchery production of more aquaculture species, the demand for Artemia cysts has continued to increase and annual consumption is now estimated at 3 500–4 000 tonnes for the production of over 900 billion crustacean postlarvae and fish fry by a hatchery industry valued at more than USD 2 billion and responsible for the final production of over 10 million tonnes of high-value aquaculture species (e.g. shrimp, prawn, crab, bass, bream, grouper, flounder, milkfish, catfish).
Although back in the 1980s and ‘90s several scientific papers, manuals and handbooks were published describing the biology of Artemia and its optimal use in aquaculture hatcheries, some of the aspects of good practice, described in these documents, might not be relevant anymore for the present larviculture situation. On the other hand, other aspects that are still very much valid are nowadays sometimes not given sufficient attention or are even entirely ignored. The purpose of this NACA webinar was thus to review the status of the use of Artemia cysts in small as well as large scale hatcheries producing different species of fish and crustaceans in Asia, Europe, and Latin America.
The webinar started with a brief introduction on the Artemia cyst hatching process and the crucial parameters to ensure optimal hatching and preparation of Artemia for use in the start feeding of larval fish and crustaceans.
Powerpoint presentations as well as videoclips documented the wide diversity of practices with Penaeid shrimp, Macrobrachium prawn and Scylla crabs in Bangladesh, Brazil, China, Ecuador, India, Thailand and Vietnam. Speakers from Greece and Spain mainly covered the use of Artemia in European seabass and seabream hatcheries.
Summarizing, daily cyst consumptions range from a few kg up to 100 kg per day in some of the biggest shrimp hatcheries (f ex in Vietnam and China). Cyst hatching tanks vary in size and shape, from a few 100L to several m³ in volume, operated at cyst densities from 1 to several kg per m³. The Artemia hatching conditions are only in rare cases strictly controlled (especially with regard to temperature, pH, light and oxygen) and might result in poor hatching and/or the harvesting of instar II or older stages that have already lost a significant amount of their nutritional value and furthermore might be loaded with high Vibrio concentrations (that bloom in the cyst hatching tank when the cysts release glycerol at the moment of breaking and appearance of the umbrella stage, preceding the release of the instar I nauplius). Surprisingly most participants in the polls admitted knowing that there is a difference between instar I and instar II stage, although many didn’t realize that Artemia nauplii – as soon as they molt into instar II stage – can become carriers of Vibrio and pose biosecurity problems in the hatchery. Overall, the presentations clearly showed that there is indeed much room for improvement in optimizing the use of Artemia cysts in aquaculture hatcheries, and this should result not only in economizing its use but especially offering a highly nutritional and Vibrio-free food to the baby fish/crustaceans.
The hypochlorite technique for cyst decapsulation is still used in many countries, except in Europe where the health (release of chlorine) and discharge (toxic effluent) problems made it prohibitive.
Several other practices with the nauplii, i.e. handling of the Artemia nauplii post hatching, especially in the small-scale hatcheries, do not follow the recommendations outlined in Artemia manuals and result in quality loss due to mechanical damage during harvesting and washing in non-submerged filters or result in further nutritional losses when nauplii, in-between feedings are stored under room-temperature conditions. On the other hand, several big hatcheries in Latin America as well as in Asia are following the state-of-the art techniques and protocols developed in the Mediterranean fish hatcheries using stainless-steel concentrator rinsing devices (welded-wedge screens) to harvest and rinse the Artemia in the most optimal conditions and store the nauplii at low temperature in fully automated controlled devices (used f ex in the milk processing industry).
Recently, a more advanced technique for separating the live nauplii from the empty cyst shells and unhatched cysts (based on the SEP-Art technology) is applied by different hatcheries, small and large. This non-invasive technique allows hatcheries to harvest high quality Artemia in a consistent and automated way, using tools equipped with magnets to separate the cysts and cyst shells from the nauplii. This technology allows more automation and less handling, resulting in a higher quality Artemia at harvest.
Several other chemical and physical techniques are also applied to improve the separation of the nauplii, although most of these techniques still need further scientific documentation & standardization.
Practices of submerging the Artemia nauplii in hot or even boiling water, even if short, should be discommended: this might kill off the Vibrios bio-accumulated in the nauplii, but will result in physical damage to the nauplii, leaching of their body fluids in the hatchery tank, creating conditions that favor bacterial development in the larval tanks, promoting the development of opportunistic bacteria such as Vibrio.
Freezing the nauplii to be able to feed the shrimp in an earlier larval stage is a valid option, provided quick freezing is performed in thin layers, preventing the formation of crystals that otherwise will provoke physical damage with similar consequences as explained above. A good alternative to feed the shrimp in an earlier stage could be the successful practice applied in mud crab hatcheries in Vietnam where the umbrella stage of Artemia of the small Vinh Chau Artemia strain is a successful alternative for rotifers in start-feeding the zoea stages of mud crab larvae.
Marine fish hatcheries in Europe were the first to adopt cold storage of Artemia nauplii and now use milk storage tanks. The technique of cold storage needs to receive much more attention as it allows to keep the Artemia under the most nutritious condition for a prolonged time, while making the production of Artemia less labor intensive as the hatching of the cysts can be concentrated in a more limited period using the resources in a more efficient way. Furthermore, live Artemia storage also allows more frequent feeding of the fish/shrimp larvae, eventually with automatic pumping devices.
Only the European marine fish hatcheries and the mud crab hatcheries in Vietnam apply the Artemia nauplii nutrient-enrichment technique to ensure optimal larval development. Although it was reported to have a beneficial effect in Penaeus monodon larviculture in Thailand, it was abandoned when the country switched to Penaeus vannamei farming.
These problems of unreliable quality of Artemia nauplii produced under suboptimal production conditions probably explain the success, especially in shrimp hatcheries, in purchasing live Artemia nauplii produced in specialized Artemia cyst hatching centers. In China, the biggest consumer of Artemia cysts, close to 50% of the hatcheries rely on this practice.
We also see more and more use of Artemia biomass (1-cm adult brine shrimp, harvested from salt ponds or lakes) in late hatchery and nursery feeding, especially in shrimp farming in China where it is offered under live, frozen, and dried forms.
In conclusion this webinar confirmed the suspicion that there are important differences in the use of Artemia cysts and in the preparation and use of brine shrimp nauplii in fish and crustacean hatcheries: many of the techniques and protocols, widely applied today, do not follow the GAPs in Artemia production as recommended by FAO in the 1996 Live Food Manual. On the other hand, new techniques and products have been developed and can result in more controlled and optimized use of Artemia cysts in hatchery practices. Therefore, an update of GAPs for Artemia cyst use in hatcheries is strongly recommended both under the form of updated manuals and documentation/demonstration materials for hands-on training sessions with hatchery staff. Hopefully hatchery managers will realize that applying more standardized protocols will not only result in using a better and more biosecure food but that they will be able to save on their Artemia cyst purchases. All efforts need to be made to optimally use Artemia as to guarantee that hatcheries deliver top quality product for stocking in the ponds or the cages.
The use of umbrella Artemia as successfully applied in the Vietnamese crab hatcheries is an interesting new development that should be considered for a wider application in aquaculture, as new source of live food in earlier larval stages be it in shrimp or in fish.
In view of the large variety of species and strains of Artemia that are now available in the market it might be time to better study their specific characteristics as to identify their most suitable application for specific species of fish and crustaceans, and this could be related to their nutritional composition, synchrony in hatching, enrichment characteristics, etc.
Finally, it might also be worthwhile to reconsider a wider use in the hatcheries of the Artemia enrichment technique, as it is now restricted to applications in marine fish and crab. This method not only allows to enhance the nutritional value of the nauplii but can also be used to do nutritional programming and as a vector to deliver for example pre- or probiotics to the fish/crustacean larvae.
Table 1: Technical programme / list of speakers
Director General, Network of Aquaculture Centres in Asia-Pacific, Bangkok, Thailand
|Briefing on webinar email@example.com|
Artemia Reference Center, Ghent University, Belgium
|Brief introduction on the Artemia cyst hatching process and its use in hatchery firstname.lastname@example.org|
Director, Samut Sakhon Coastal Aquaculture Research and Development Center, Thailand
|The current status of the use of Artemia cysts in shrimp and fish hatcheries in Thailand
|Trinh Trung Phi
Technical Director, VIET-UC shrimp hatcheries, Vietnam
|VIET-UC shrimp hatcheries, Vietnamemail@example.com|
|Nguyen Van Hoa
Can Tho University, Vietnam
|Use of Artemia cysts in crustacean hatcheries in the Mekong Delta, Vietnamfirstname.lastname@example.org|
|Nageswara Rao P.V.
All India Hatchery Association
|Status of Artemia cyst usage, hatching and application in shrimp hatcheries in Indiaemail@example.com|
|Muhammad Meezanur Rahman and Khin Mau U
|Artemia cyst hatching and application in shrimp and prawn hatcheries in Bangladeshfirstname.lastname@example.org|
|Sui Liying1, Zhang Bo1 and Gao Song2
1. Asian Regional Artemia Reference Center, Tianjin University of Science and Technology, China
2. China Artemia Association
|Use of Artemia cysts in hatchery in Chinaemail@example.com|
Tapies Hatchery, PHILOSOFISH SA, Greece
Fry Operation Manager, AVRAMAR, Spain
|Use of Artemia in sea bream, sea bass and meager larvae firstname.lastname@example.org|
|Ecuador: Hatching practices for Artemia email@example.com|
|Marcos R. Camara
Federal University of Rio Grande do Norte, Brazil
|Status of Artemia cyst use in shrimp hatcheries in North-east Brazilfirstname.lastname@example.org|
|Artemia cyst hatching in the Aquatec and Tecmares email@example.com|
Communications Manager, Network of Aquaculture Centres in Asia-Pacific
|Host / MCfirstname.lastname@example.org|
Video recordings of technical presentations
Recordings of the technical presentations are available on Youtube at the link below: