4.1. Introduction, biology and ecology of Artemia

4.1.1. Introduction
4.1.2. Biology and ecology of Artemia
4.1.3. Literature of interest

Gilbert Van Stappen
Laboratory of Aquaculture & Artemia Reference Center
University of Gent, Belgium

4.1.1. Introduction

Among the live diets used in the larviculture of fish and shellfish, nauplii of the brine shrimp Artemia constitute the most widely used food item. Annually, over 2000 metric tons of dry Artemia cysts are marketed worldwide for on-site hatching into 0.4 mm nauplii. Indeed, the unique property of the small branchiopod crustacean Artemia to form dormant embryos, so-called ‘cysts’, may account to a great extent to the designation of a convenient, suitable, or excellent larval food source that it has been credited with. Those cysts are available year-round in large quantities along the shorelines of hypersaline lakes, coastal lagoons and solar saltworks scattered over the five continents. After harvesting and processing, cysts are made available in cans as storable ‘on demand’ live feed. Upon some 24-h incubation in seawater, these cysts release free-swimming nauplii that can directly be fed as a nutritious live food source to the larvae of a variety of marine as well as freshwater organisms, which makes them the most convenient, least labour-intensive live food available for aquaculture. Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930’s, when several investigators found that it made an excellent food for newly-hatched fish larvae. During the 1940’s, most commercially available brine shrimp cysts represented collections from natural saline lakes and coastal saltworks. With the growing interest for tropical hobby fish in the late 1940’s, commercial value was attached to brine shrimp, thereby establishing a new industry. Early pioneers exploited in 1951 the cyst production of Artemia at the Great Salt Lake in Utah, USA. First harvests of the lake yielded 16 tons of finished product. During the mid-1950’s, commercial attention for brine shrimp was turned to controlled sources for production in the San Francisco Bay region. Here it was found that brine shrimp and their cysts could be produced as a by-product of solar saltworks. Since salt production entails management of the evaporation process, yearly cyst and biomass productions could be roughly predicted. In the 1960’s, commercial provisions originated from these few sources in North America and seemed to be unlimited. However, with the expansion of aquaculture production in the 1970’s, the demand for Artemia cysts soon exceeded the offer and prices rose exponentially, turning Artemia into a bottleneck for the expansion of the hatchery aquaculture of marine fishes and crustaceans. In particular, many developing countries could hardly afford to import the very expensive cysts.

At the Kyoto FAO Technical Conference on Aquaculture in 1976 it was claimed that the cyst shortage was an artificial and temporary problem. During the following years research efforts were made to prove the possibility of local production of Artemia in developing countries.

At present, Artemia is being produced and exploited on the five continents. Despite this, a large part of the cyst market is still supplied by harvests from one location, the Great Salt Lake. This situation makes the market still extremely vulnerable to climatological and/or ecological changes in this lake, which has been illustrated by the unusually low cyst harvests in the seasons 1993-1994 and mainly 1994-1995.

Already in the late seventies it appeared that the nutritional value of Artemia, especially for marine organisms, was not constant but varied among strains and within batches of each strain, causing unreliable outputs in marine larviculture. Through multidisciplinary studies in the eighties both the causes for the nutritional variability in Artemia and the methods to improve poor-quality Artemia were identified. Genotypic and phenotypic variation (i.e. cyst size, cyst hatching characteristics, caloric content and fatty acid composition of the nauplii) determine if a particular cyst product is suitable for hatchery use of specific fish or shrimp species.

By bio-encapsulating specific amounts of particulate or emulsified products rich in highly unsaturated fatty acids in the brine shrimp metanauplii, the nutritional quality of the Artemia can be further tailored to suit the predators’ requirements. Application of this method of bio-encapsulation, also called Artemia enrichment or boosting, has had a major impact on improved larviculture outputs, not only in terms of survival, growth and success of metamorphosis of many species of fish and crustaceans, but also with regard to their quality, e.g. reduced incidence of malformations, improved pigmentation and stress resistance. The same bio-encapsulation method is now being developed for oral delivery of vitamins, chemotherapeutics and vaccines.

Furthermore, a better knowledge of the biology of Artemia was at the origin of the development of other Artemia products, such as disinfected and decapsulated cysts, various biomass preparates, which presently have application in hatchery, nursery and broodstock rearing. All these developments resulted in optimized and cost-effective applications of this live food in hatchery production.

4.1.2. Biology and ecology of Artemia

4.1.2.1. Morphology and life cycle
4.1.2.2. Ecology and natural distribution
4.1.2.3. Taxonomy
4.1.2.4. Strain-specific characteristics

4.1.2.1. Morphology and life cycle

In its natural environment at certain moments of the year Artemia produces cysts that float at the water surface (Fig. 4.1.1.) and that are thrown ashore by wind and waves. These cysts are metabolically inactive and do not further develop as long as they are kept dry. Upon immersion in seawater, the biconcave-shaped cysts hydrate, become spherical, and within the shell the embryo resumes its interrupted metabolism. After about 20 h the outer membrane of the cyst bursts (= “breaking”) and the embryo appears, surrounded by the hatching membrane (Fig. 4.1.2.). While the embryo hangs underneath the empty shell (= “umbrella” stage) the development of the nauplius is completed and within a short period of time the hatching membrane is ruptured (= “hatching”) and the free-swimming nauplius is born (Fig.4.1.3.).

Figure 4.1.1. Harvesting of brine shrimp cysts from a saltpond.

Figure 4.1.2. Cyst in breaking stage. (1) nauplius eye.

Figure 4.1.3. Embryo in “umbrella” stage (left) and instar I nauplius (right). (1) nauplius eye; (2) antennula; (3) antenna; (4) mandible.

The first larval stage (instar I; 400 to 500 µm in length) has a brownish-orange colour, a red nauplius eye in the head region and three pairs of appendages: i.e. the first antennae (sensorial function), the second antennae (locomotory + filter-feeding function) and the mandibles (food uptake function). The ventral side is covered by a large labrum (food uptake: transfer of particles from the filtering setae into the mouth). The instar I larva does not take up food as its digestive system is not functional yet; it thrives completely on its yolk reserves.

After about 8 h the animal molts into the 2nd larval stage (instar II). Small food particles (e.g. algal cells, bacteria, detritus) ranging in size from 1 to 50 µm are filtered out by the 2nd antennae and ingested into the functional digestive tract.

The larva grows and differentiates through about 15 molts. Paired lobular appendages are appearing in the trunk region and differentiate into thoracopods (Fig. 4.1.4.). On both sides of the nauplius lateral complex eyes are developing (Fig. 4.1.5. and 4.1.6.). From the 10^th instar stage on, important morphological as well as functional changes are taking place: i.e. the antennae have lost their locomotory function and undergo sexual differentiation. In males (Fig. 4.1.6. and 4.1.8.) they develop into hooked graspers, while the female antennae degenerate into sensorial appendages (Fig. 4.1.11.). The thoracopods are now differentiated into three functional parts (Fig. 4.1.13.), namely the telopodites and endopodites (locomotory and filter-feeding), and the membranous exopodites (gills).

Figure 4.1.4. Instar V larva. (1) nauplius eye; (2) lateral complex eye; (3) antenna; (4) labrum; (5) budding of thoracopods; (6) digestive tract.

Figure 4.1.5. Head and anterior thoracic region of instar XII. (1) nauplius eye; (2) lateral complex eye; (3) antennula; (4) antenna; (5) exopodite; (6) telopodite; (7) endopodite.

Adult Artemia (± 1 cm in length) have an elongated body with two stalked complex eyes, a linear digestive tract, sensorial antennulae and 11 pairs of functional thoracopods (Fig. 4.1.10. and 4.1.11.). The male (Fig. 4.1.10.) has a paired penis in the posterior part of the trunk region (Fig. 4.1.9.). Female Artemia can easily be recognized by the brood pouch or uterus situated just behind the 11th pair of thoracopods (Fig. 4.1.9. and 4.1.11.). Eggs develop in two tubular ovaries in the abdomen (Fig. 4.1.7.). Once ripe they become spherical and migrate via two oviducts into the unpaired uterus.

Figure 4.1.6. Head and thoracic region of young male. (1) antenna; (2) telopodite; (3) exopodite.

Figure 4.1.7. Posterior thoracic region, abdomen and uterus of fertile female. (1) ripe eggs in ovary and oviduct.

Figure 4.1.8. Head of an adult male. (1) antenna; (2) antennula; (3) lateral complex eye; (4) mandible.

Fertilized eggs normally develop into free-swimming nauplii (= ovoviviparous reproduction) (Fig. 4.1.12.) which are released by the mother. In extreme conditions (e.g. high salinity, low oxygen levels) the embryos only develop up to the gastrula stage. At this moment they get surrounded by a thick shell (secreted by the brown shell glands located in the uterus), enter a state of metabolic standstill or dormancy (diapause) and are then released by the female (= oviparous reproduction) (Fig. 4.1.14.). In principle both oviparity and ovoviviparity are found in all Artemia strains, and females can switch in-between two reproduction cycles from one mode of reproduction to the other. The cysts usually float in the high salinity waters and are blown ashore where they accumulate and dry. As a result of this dehydration process the diapause mechanism is generally inactivated; cysts are now in a state of quiescence and can resume their further embryonic development when hydrated in optimal hatching conditions.

Under optimal conditions brine shrimp can live for several months, grow from nauplius to adult in only 8 days time and reproduce at a rate of up to 300 nauplii or cysts every 4 days.

Figure 4.1.9. Artemia couple in riding position. (1) uterus; (2) penis.

Figure 4.1.10. Adult male.

Figure 4.1.11. Adult female.

Figure 4.1.12. Uterus of ovoviviparous Artemia filled with nauplii (first larvae are being released). (1) ovary with eggs.

Figure 4.1.13. Detail of anterior thoracopods in adult Artemia. (1) exopodite; (2) telopodite; (3) endopodite.

Figure 4.1.14. Uterus of oviparous Artemia filled with cysts. (1) brown shell glands (darker colour).

4.1.2.2. Ecology and natural distribution

Artemia populations are found in about 500 natural salt lakes and man-made salterns scattered throughout the tropical, subtropical and temperate climatic zones, along coastlines as well as inland (Fig. 4.1.15.). This list still remains provisional as more extensive survey work should lead to the discovery of many more Artemia biotopes in different parts of the world (Table 4.1.1.). The distribution of Artemia is discontinuous: not all highly saline biotopes are populated with Artemia. Although brine shrimp thrive very well in natural seawater, they cannot migrate from one saline biotope to another via the seas, as they depend on their physiological adaptations to high salinity to avoid predation and competition with other filter feeders. Its physiological adaptations to high salinity provide a very efficient ecological defense against predation, as brine shrimp possess:

· a very efficient osmoregulatory system;

· the capacity to synthesize very efficient respiratory pigments to cope with the low O₂ levels at high salinities;

· the ability to produce dormant cysts when environmental conditions endanger the survival of the species.

Artemia therefore, is only found at salinities where its predators cannot survive (³ 70 g.l^-1). As a result of extreme physiological stress and water toxicity Artemia dies off at salinities close to NaCl saturation, i.e. 250 g.l^-1 and higher.

Different geographical strains have adapted to widely fluctuating conditions with regard to temperature (6-35°C), salinity and ionic composition of the biotope. Thalassohaline waters are concentrated seawaters with NaCl as major salt. They make up most, if not all, of the coastal Artemia habitats where brines are formed by evaporation of seawater in salt pans. Other thalassohaline habitats are located inland, such as the Great Salt Lake in Utah, USA. Athalassohaline Artemia biotopes are located inland and have an ionic composition that differs greatly from that of natural seawater: there are sulphate waters (e.g. Chaplin Lake, Saskatchewan, Canada), carbonate waters (e.g. Mono Lake, California, USA), and potassium-rich waters (e.g. several lakes in Nebraska, USA).

Artemia is a non-selective filter feeder of organic detritus, microscopic algae as well as bacteria. The Artemia biotopes typically show a very simple trophical structure and low species diversity; the absence of predators and food competitors allows brine shrimp to develop into monocultures. As high salinity is the common feature determining the presence of Artemia, the impact of other parameters (temperature, primary food production, etc.) may at most affect the abundance of the population and eventually cause a temporary absence of the species.

As Artemia is incapable of active dispersion, wind and waterfowl (especially flamingos) are the most important natural dispersion vectors; the floating cysts adhere to feet and feathers of birds, and when ingested they remain intact for at least a couple of days in the digestive tract of birds. Consequently the absence of migrating birds is probably the reason why certain areas that are suitable for Artemia (e.g. salinas along the northeast coast of Brazil) are not naturally inhabited by brine shrimp.

Next to the natural dispersion of cysts, deliberate inoculation of Artemia in solar salt works by man has been a common practice in the past. Since the seventies man has been responsable for several Artemia introductions in South America and Australia, either for salt production improvement or for aquaculture purposes. Additionally, temporal Artemia populations are found in tropical areas with a distinct wet and dry season (monsoon climate), through inoculation in seasonal salt operations (e.g. Central America, Southeast Asia).

Figure 4.1.15. The world distribution of Artemia.

Table 4.1.1. World distribution of Artemia.

Country	Locality	Sex	Species
Artemia sites in Africa
Algeria	Chegga Oase	-	-
	Chott Djeloud	-	-
	Chott Ouargla	-	-
	Dayet Morselli	-	-
	Gharabas Lake	-	-
	Sebket Djendli	-	-
	Sebket Ez Zemouk	-	-
	Sebket Oran	-	-
	Tougourt	-	-
Egypt	Port Fouad	B	A. sal
	Wadi Natron	B	A. sal
	Qarun Lake	P	A. par
Kenya	Elmenteita	-	-
Libya	Mandara	B	A. sp
	Ramba-Az-Zallaf (Fezzan)	-	-
	Quem el Ma	-	-
	Trouna	-	-
	Gabr Acun (Fezzan)	-	-
Madagascar	Salins de Diego Suarez	-	-
	Ankiembe saltworks	P(3n)	A. par
	Ifaty saltworks	B	A. fra
Morocco	Larache	P	A. par
	Moulaya estuary	-	-
	Qued Ammafatma	-	-
	Qued Chebeica	-	-
	Sebket Bon Areg	-	-
	Sebket Zima	-	-
Mozambique	Lagua Quissico	P	A. par
Namibia	Vineta Swakopmund	P(2n, 4n)	A. par
Niger	Teguidda In Tessoun	-	-
Senegal	Dakar	-	-
	Lake Kayar	-	-
	Lake Retba	-	-
South Africa	Couga Salt Flats	-	-
	Swartkops	-	-
Tunisia	Bekalta	B	A. sal
	Chott Ariana	B	A. sal
	Chott El Djerid	-	-
	Megrine	B	A. sal
	Sebket Kowezia	-	-
	Sebket mta Moknine	B	A. sal
	Sebket Sidi el Hani	-	-
	Sfax	B	A. sal
Artemia sites in Australia and New Zealand
New Zealand	Lake Grassmere	B	A. fra
Queensland	Bowen	-	-
	Port Alma	B	A. fra
	Rockhampton	B	A. fra
South Australia	Dry Creek, Adelaide	P	A. par
West Australia	Dampier	-	-
	Lake Mc Leod	-	-
	Port Hedland	P	A. par
	Rottnest Island	P	A. par
	Shark Bay	P,B	A.par,A.fra
Artemia sites in North America
Canada	Akerlund Lake	B	A. sp
	Alsask Lake	B	A. sp
	Aroma Lake	B	A. sp
	Berry Lake	B	A. sp
	Boat Lake	B	A. sp
	Burn Lake	B	A. sp
	Ceylon Lake	B	A. sp
	Chain Lake	B	A. sp
	Chaplin Lake	B	A. fra
	Churchill	B	A. sp
	Coral Lake	B	A. sp
	Drybore Lake	B	A. sp
	Enis Lake	B	A. sp
	Frederick Lake	B	A. sp
	Fusilier Lake	B	A. sp
	Grandora Lake	B	A. sp
	Gull Lake	B	A. sp
	Hatton Lake	B	A. sp
	Horizon Lake	B	A. sp
	Ingerbright Nath	B	A. sp
	Landis Lake	B	A. sp
	La Perouse	B	A. sp
	Little Manitou Lake	B	A. fra
	Lydden Lake	B	A. sp
	Mawer Lake	B	A. sp
	Meacham Lake	B	A. sp
	Muskiki Lake	B	A. sp
	Neola Lake	B	A. sp
	Oban Lake	B	A. sp
	Richmond Lake	B	A. sp
	Shoe Lake	B	A. sp
	Snakehole Lake	B	A. sp
	Sybouts Lake-East	B	A. sp
	Sybouts Lake-West	B	A. sp
	Verlo West	B	A. sp
	Vincent Lake	B	A. sp
	Wheatstone Lake	B	A. sp
	Whiteshore Lake	B	A. sp
USA Arizona	Kiatuthlana Red Pond	B	A. fra
	Kiatuthlana Green Pond	B	A. fra
USA California	Carpinteria Slough	B	A. sp
	Chula Vista	B	A. sp
	Mono Lake	B	A.f. mon
	Moss Landing, Monterey Bay	B	A. fra
	Owens Lake	B	A. sp
	San Diego	B	A. sp
	San Francisco Bay	B	A. fra
	San Pablo Bay	B	A. fra
	Vallejo West Pond	B	A. sp
USA Hawaii	Christmas Islands	B	A. sp
	Hanapepe	B	A. sp
	Laysan Atoll	B	A. fra
USA Nebraska	Alkali Lake	B	A. sp
	Ashenburger Lake	B	A. sp
	Antioch (Potash)Lake	B	A. fra
	Cook Lake	B	A. sp
	East Valley Lake	B	A. sp
	Grubny Lake	B	A. sp
	Homestead Lake	B	A. sp
	Jesse Lake	B	A. fra
	Johnson Lake	B	A. sp
	Lilly Lake	B	A. sp
	Reno Lake	B	A. sp
	Richardson Lake	B	A. fra
	Ryan Lake	B	A. sp
	Sheridan County Lake	B	A. sp
	Sturgeon Lake	B	A. fra
USA Nevada	Fallon Pond	B	A. fra
USA North Dakota	Miller Lake	B	A. sp
	Stink (Williams) Lake	B	A. sp
USA New Mexico	Laguna del Perro	B	A. sp
	Loving Salt Lake	B	A. sp
	Quemado	B	A. fra
	Zuni Salt Lake	B	A. fra
USA Oregon	Lake Abert	B	A. sp
USA Texas	Cedar Lake	B	A. fra
	McKenzies Playa	B	A. sp
	Mound Playa	B	A. sp
	Playa Thahoka	B	A. sp
	Raymondville	B	A. sp
	Rich Playa	B	A. sp
	Snow drop Playa	B	A. sp
USA Utah	Great Salt Lake	B	A. fra
USA Washington	Cameron Lake	B	A. fra
	Deposit Thirteen	B	A. fra
	Penley Lake	B	A. fra
	Hot (Bitter) Lake	B	A. fra
	Omak Plateau	B	A. sp
	Soap Lake	B	A. sp
Artemia sites in Central America
Bahamas	Great Inagua	B	A. sp
	Long Island	B	A. sp
	San Salvador	B	A. sp
Brit. Virgin Islands	Anegada	B	A. sp
Carribean Islands	Antigua	B	A. sp
	St. Kitts	B	A. sp
	St. Martin	B	A. sp
	South Caicos	B	A. sp
Costa Rica	Gulfo Nicova	B	A. sp
	Bahia salinas, Guanacaste	B	A. fra
Dominican Republic	Isla Cabra	B	A. sp
	Las Calderas	B	A. sp
	Monte Cristi	B	A. sp
	Puerto Alejandro	B	A. sp
	Punta Salinas	B	A. sp
Haiti	Grandes salines	B	A. fra
Mexico Baja Calif. Norte	San Quintin	B	A. fra
Mexico Baja Calif. Sur	Pichilingue, La Paz	B	A. fra
	Guerrero Negro	B	A. fra
	Isla del Carmen	B	A. fra
Mexico Sonora	Laguna de Yavaros	B	A. fra
Mexico Coahuila	Salinas 5 km SE Cuatrocienegas	B	A. sp
Mexico Chiapas	Laguna del Mar Muerto	B	A. sp
	La Joya	B	A. sp
	Buenavista	B	A. sp
	Los Palos	B	A. sp
	Solo Dios	B	A. sp
	Carretas	B	A. sp
	Pereyra	B	A. sp
	Chanchuto	B	A. sp
	Panzacola	B	A. sp
Mexico Estado de Mexico	Brine El Caracol, Sosa Texcoco	B	A. sp
Mexico Oaxaca	Ponds W. Salina Cruz	B	A. sp
Mexico San Luis Potosi	Las Salinas	B	A. sp
Mexico Sinaloa	Bahia de Ceuta	B	A. sp
Mexico Yucatan	San Crisanto	B	A. sp
	Celestun	B	A. sp
	Chuburna	B	A. sp
	Xtampu	B	A. sp
	Las Coloradas	B	A. sp
Netherlands Antilles	Aruba	B	A. sp
	Bonaire Duinmeer	B	A. fra
	Gotomeer	B	A. sp
	Pekelmeer	B	A. sp
	Martinus	B	A. sp
	Slagbaai	B	A. sp
	Curaçao Fuik	B	A. sp
	Rifwater	B	A. sp
Nicaragua	Salinas Grandes, Leon	B	A. fra
Puerto Rico	Bahia Salinas	B	A. fra
	Bogueron	B	A. sp
	Cabo Rojo	B	A. sp
	La Parguera	B	A. sp
	Ponce	B	A. sp
	Tallaboa salterns	B	A. fr
Artemia sites in South America
Argentina	Bahia Blanca	B	A. sp
	Buenos Aires	B	A. per
	Hidalgo	B	A. per
	Mar Chiquita	B	A. sp
Bolivia	Lake Canapa	B	A. sp
	Lake Chulluncani	B	A. sp
	Lake Hedonia	B	A. sp
	Lake Poopo	B	A. sp
Brazil	Aracati	B	A. sp
	Cabo Frio	B	A. fra
	Fortaleza	B	A. sp
	Icapui	B	A. sp
	Macau	B	A. fra
	Mundau	B	A. sp
Chile	Salar de Surire	B	A. sp
	Playa Yape (Iquique)	B	A. sp
	Salar de Pintados (I Region)	B	A. sp
	Salar de Llamara (II Region)	B	A. sp
		B	A. fra
	Puerto Viejo (Copiapo)	B	A. sp
	La Pampilla (Coquimbo)	B	A. sp
	Palo Colorado (Los Vilos)	B	A. sp
	Salinas de Cahuil (Pichilemu)	B	A. sp
	Salinas de Constitución (VII Región)	B	A. sp
Colombia	Galerazamba	B	A. sp
	Manaure	B	A. sp
Ecuador	Galapagos (S.Salvador)	B	A. fra
	Pacoa	B	A. sp
	Salinas	B	A. sp
Peru	Caucato	B	A. sp
	Chicama	B	A. sp
	Chilca	B	A. sp
	Estuario de Virrila	B	A. sp
	Guadalupe	B	A. sp
	Pampa de Salinas	B	A. sp
	Pampa Playa Chica	B	A. sp
	Puerto Huarmey	B	A. sp
	Tumbes	B	A. sp
Venezuela	Boca Chica	B	A. sp
	Coya Sal	B	A. sp
	Coche	B	A. sp
	Coro Coastline	B	A. sp
	La Orchila	B	A. sp
	Las Aves	B	A. sp
	Los Roques	B	A. sp
	Port Araya	B	A. sp
	Tucacas	B	A. sp
Artemia sites in Asia
P.R. China Liaoning	Jinzhou	P	A. par
	Yingkou	P(2, 4, 5n)	A. par
	Dongjiagou	P(2n)	A. par
	Pulandian	P(2n)	A. par
	Lushun	P(2, 4, 5n)	A. par
	Fuzhouwan	P	A. par
P.R. China Hebei	Nanpu	P(2n)	A. par
	Luannan	P	A. par
	Daqinghe	P	A. par
	Huanghua	P(2n)	A. par
	Shangyi	B	A. sin
	Zhangbei	B	A. sin
	Kangbao	B	A. sin
P.R. China Tianjin	Hangu	P(2n)	A. par
	Tanggu	P(2, 4, 5n)	A. par
P.R. China Shandong	Chengkou	P(2n)	A. par
	Yangkou	P(2n)	A. par
	Dongfeng	P(2, 5n)	A. par
	Gaodao	P	A. par
	Xiaotan	P	A. par
	Nanwan	P	A. par
	Jimo	P	A. par
P.R. China Jiangsu	Xuyu	P	A. par
	Lianyungang	P	A. par
P.R. China Zhejiang	Zhanmao	P	A. par
	Shunmu	P	A. par
	Zhujiajian	P	A. par
P.R. China Fujian	Shanyao	P	A. par
	Xigang	P	A. par
	Huian	P	A. par
P.R. China Guangdong		P	A. par
P.R. China Hainan	Dongfang	P	A. par
	Yinggehai	P(2, 4, 5n)	A. par
P.R. China Xinjiang	Aibi	P(2, 4n)	A. par
	Dabancheng	P(2, 3, 4, 5n)	A. par
	Balikun	P(2,4n)	A. par
	Aletai	B	A. sp
P.R. China Tibet	Yanjing	B	A. sp
	Shenzha	B	A. sp
	Bange	-	-
	Gaize	-	-
	Geji	-	-
	Zhangchaka	-	-
	Wumacuo	-	-
	Jibuchaka	-	-
	Dongcuo	-	-
P.R. China Qinghai	Gahai	P(2n)	A. par
	Xiaocaidan	P	A. par
	Dacaidan	P	A. par
	Suban	P	A. par
	Keke	P(4n)	A. par
	Chaka	P	A. par
	Tuosu	P	A. par
P.R. China Gansu	Gaotai	B	A. sp
P.R. China Inner Mongolia	Haolebaoji(Y)	B	A. sin
(Y = Yimeng Area)	Haotongyin(Y)	B	A. sin
(X = Ximeng Area)	Taigemiao(Y)	B	A. sin
	Ejinor(X)	B	A. sin
	Beidachi(Y)	B	A. sin
	Jilantai	B	A. sin
	Wuqiangi	B	A. sin
	Shanggendalai(X)	B	A. sin
	Dagenor(X)	B	A. sin
	Bayannor(X)	B	A. sin
	Zhunsaihannor	B	A. sin
	Erendabusen	B	A. sin
	Chagannor(X)	B	A. sin
	Huhetaolergai(Y)	B	A. sin
	Hangjinqi	B	A. sin
P.R. China Ningxia		-	-
P.R. China Shaanxi	Dingbian	-	-
P.R. China Shanxi	Yuncheng	B	A. sin
India Rajasthan	Didwana	-	-
	Sambhar Lake	-	-
India Gujarat	Gulf of Kutch	P	A. par
	Balamba salterns	P	A. par
	Mithapur	P	A. par
	Jamnagar	-	-
India Bombay	Vadala	-	-
	Bhayander	P	A. par
	Bahinder	-	-
India Madras	Kelambakkam	-	-
	Vedaranyam	-	-
India Tuticorin	Veppalodai	-	-
	Pattanamaruthur	-	-
	Spic Nagar	-	-
	Thirespuram	-	-
	Karsewar Island	-	-
	Saltwater springs	P	A. par
	Harbour	-	-
India Kanyakumari	Thamaraikulam	P	A. par
Iraq	Abu-Graib, Baghdad	P	A. par
	Basra	-	-
	Dayala	-	-
	Mahmoodia	-	-
Iran	Urmia Lake	B	A. urm
	Schor-Gol	-	-
	Shurabil	-	-
	Athlit	-	-
Israel	Eilat North	P	A. par
	Eilat South	-	-
Japan	Chang Dao	-	-
	Tamano	-	-
	Yamaguchi	P	A. par
Kuwait		-	-
Korea	Pusan	-	-
Pakistan	Karachi saltworks	P	A. par
Sri Lanka	Bundala	-	-
	Hambantota	-	-
	Palavi	-	-
	Putallam	P	A. par
Taiwan	Peinan Salina	-	-
	Beimen	B	A. sp
Turkey	Balikesir, Aivalik	-	-
	Camalti, Izmir	P	A. par
	Tuz Golii	-	-
	Ankara Salt Lake	-	-
	Konya Karapinar-Meke Salt Lake	-	-
	Imbros	-	-
Artemia sites in Europe
Bulgaria	Burgas	P	A. par
	Pomorye	-	-
Croatia	Secovlje, Portoroz	P(4n)	A. par
	Strunjan	P	A. par
	Ulcinj	P	A. par
Cyprus	Akrotiri Lake	-	-
	Larnaca Lake	B	A. sal
France	Aigues Mortes	P	-
	Carnac-Trinité sur Mer	-	-
	Guérande-le Croisic	P	A. par
	La Palme	-	-
	Lavalduc	P	A. par
	Mesquer-Assérac	-	-
	Porte La Nouvelle	-	-
	Salin de Berre	P	A. par
	Salin de Fos	-	-
	Salin de Giraud	P	A. par
	Salins d’Hyères	-	-
	Salin des Pesquiers	-	-
	Sète	P	A. par
Greece	Citros, Pieria	P(4n)	A. par
	Megalon Embolon, Thessaloniki	P(4n)	A. par
	Kalloni, Lesbos	P(4n)	A. par
	Polychnitos, Lesbos	P(4n)	A. par
	Mesolongi	P	A. par
	Milos Island	P	A. par
Italy	Quartu or salina di Poetto, Cagliary	B	A. sal
	Carloforte, Sardinia	B	A. sal
	Cervia, Ravenna	P(4n)	A. par
	Commachio, Ferrara	P(4n)	A. par
	Margherita di Savoia, Foggia	P(2,4n)	A. par
	Sant’ Antioco, Sardinia	B	A. sal
	Santa Gilla, Sardinia	P(2n)	A. par
	Siracuse, Sicily
	Tarquinia, Viterbo	B	A. sal
	Trapani, Sicily	B	A. sal
Portugal	Alcochete	P	A. par
	Tejo estuary	-	-
	Sado estuary	-	-
	Ria de Aveiro	-	-
	Ria de Farc	-	-
Romania	Lake Techirghiol	P	A. par
	Lacul Sârat Brâila	P	A. par
	Movila Miresii	-	-
Romania Slâric Prahova	Baia Baciului	P	A. par
Romania Slâric Prahova	Baia Neagrâ, SP	P	A. par
	Baia Verde I, SP	P	A. par
	Baia Verde II, SP	P	A. par
	Baia Verde III, SP	P	A. par
	Baia Rosie, SP	P	A. par
Romania Telega	Telega Bâi	P	A. par
	Telega II	P	A. par
	Telega III	P	A. par
	Ocra Sibiului	P?
	Sovata	P?
Spain Alava	Añana	P(4n)	A. par
Spain Albacete	Petrola	P(4n)	A. par
	Pinilla	P(4n)	A. par
Spain Alicante	Bonmati, S.Pola	B, P(2, 4n)	mixed
	Bras de Port, S.Pola	B	m
	Calpe	P(2n)	A. par
	La Mata	P(2n)	A. par
	Molina del Segura	B
	Salinera Espanola, S. Pola	B
	Villena	B
Spain Burgos	Poza de la Sal	B	A. sp
Spain Cadiz	Sanlucar de Barrameda	P	A. par
	Dos hermanos	B, P(2n)	mixed
	San Eugenio	B, P(2n)	mixed
	San Felix	B	A. sal
	San Fernando	B	A. sal
	San Juan	B, P	mixed
	San Pablo	B, P	mixed
	Santa Leocadia	B, P	mixed
	Barbanera	B	A. sal
Spain Canary islands	Janubio, Lanzarote	P(2n)	A. par
Spain Cordoba	Encarnacion	P(4n)	A. par
	Puente Montilla	P(4n)	A. par
Spain Formentera	Salinera Espanola,	B	A. sal
Spain Guadalajara	Armalla	P(4n)	A. par
	Imon	P(4n)	A. par
	Olmeda	P(4n)	A. par
	Rienda	P(4n)	A. par
Spain Huelva	Ayamonte	P(2n)	A. par
	Lepe	P(2n)	A. par
	Isla Cristina	P(2n)	A. par
	San Juan del Puerto	B	A. sal
Spain Huesca	Rolda	P	A. par
	Peralta de la Sal	P	A. par
Spain Ibiza island	Salinera Espanola
Spain Jaen	San Carlos
	Don Benito
Spain Malaga	Fuente de Piedra
Spain Mallorca	Campos del Puerto	B	A. sal
Spain Murcia	San Pedro del Pinatar	B	A. sal
	Jumilla	B	A. sal
	sal. Punta Galera	B	A. sal
	sal. Catalana	B	A. sal
Spain Soria	Medinaceli	P(4n)	A. par
Spain Tarragona	Delta del Ebro	P(4n)	A. par
Spain Teruel	Arcos de las Salinas	P(4n)	A. par
Spain Zaragoza	Chiprana	P(4n)	A. par
	Bujaralo	P(4n)	A. par
Artemia sites in former USSR
Russia	Bolshoe Otar Mojnaksho
	Bolshoe Yarovoe	P
	Maloe Yarovoe/Mojnakshoe/Dscharylgach
	Ghenicheskoe
	Karachi Lake
	Kujalnic liman	P	A. par
	Mangyshlak peninsula
	Schekulduk	P
	Tanatar	B	A. par
	Kulundinskoe	P
	Soljonoe	P
	Mirabilit	P
	Bolshoe Shklo	P	A. par
	Kurichye	P
	Buazonsor	P
	Mormishanskoe A	P
	Mormishanskoe B	P
	Kutchukskoe	P
		P
Kazakhstan	Maraldi	P
	Sejten	P
Turkmenistan		P
Ukraina	Popovskoe (=Ojburgskoe)	P
	Tchokrakskoe	B
	Tobetchikskoe	P
	Shtormovoe	B
	Sakskoe
	Sasyk

P = parthenogenetic strain
B = bisexual strain
A. par = Artemia parthenogenetica
A. sal = Artemia salina (= A. tunisiana)
A. fr = Artemia franciscana
A. fr. mon = Artemia franciscana monica
A. per = Artemia persimilis
A. urm = Artemia urmiana
A. sin = Artemia sinica
A. sp = Artemia species (unknown)

4.1.2.3. Taxonomy

The genus Artemia is a complex of sibling species and superspecies, defined by the criterion of reproductive isolation. Early taxonomists assigned species names to populations with different morphologies, collected at different temperatures and salinities. Later on, the profusion of names was abandoned and all brine shrimp was referred to as Artemia salina Linnaeus 1758. Some authors continue this practice today. Generally, different names are assigned to reproductively isolated populations or clusters of populations:

· A. salina Linnaeus 1758: Lymington, England (now extinct), Mediterranean area;

· A. tunisiana Bowen and Sterling 1978 synonym of A. salina;

· A. parthenogenetica Barigozzi 1974, Bowen and Sterling 1978: Europe, Africa, Asia, Australia;

· A. urmiana Gunther 1900: Iran;

· A. sinica Yaneng 1989: Central and Eastern Asia;

· A. persimilis Piccinelli and Prosdocimi 1968: Argentina;

· A. franciscana superspecies: Americas, Carribean and Pacific islands, including populations reproductively isolated in nature like A.(franciscana) franciscana Kellogg 1906 and A.(franciscana) monica Verrill 1869 (Mono Lake, California);

· Artemia sp. Pilla and Beardmore 1994: Kazakhstan.

The coexistence of two species in the same saline habitat is possible: mixtures of parthenogenetic and zygogenetic populations have been reported in Mediterranean salterns. In addition, commercial aquaculture ventures have seeded salterns with imported cysts on many occasions; A. Franciscana being introduced throughout Asia, Australia, and South America over the last 20 years. Because new populations are constantly being characterised, scientists are urged to use the denomination Artemia sp. unless they have sufficient biochemical, cytogenetic or morphological evidence to identify the species name.

The worldwide distribution of brine shrimp in a variety of isolated habitats, each one characterised by its own ecological conditions, has furthermore resulted in the existence of numerous geographical strains, or genetically different populations within the same sibling species; in particular the parthenogenetic Artemia with its di-, tri-, tetra- and pentaploid populations display a wide genotypic variation. Among these strains a high degree of genetic variability as well as a unique diversity in various quantitative characteristics have been observed. Some of these characteristics (i.e. the nutritional value of freshly-hatched nauplii) are phenotypical, and change from year to year or season to season. Others, however (i.e. cyst diameter, growth rate, resistance to high temperature) are strain specific and remain relatively constant, (i.e. they have become genotypical as a result of long-term adaptations of the strain to the local conditions; see chapter 4.1.2.4).

4.1.2.4. Strain-specific characteristics

INTRODUCTION

While the nutritional value can be manipulated, other qualities favourable for aquaculture use can be obtained by selection of strains and/or their cross breeds. Although until recently over 90% of all marketed cysts originated from the Great Salt Lake, Artemia cysts are commercially available from various production sources in America, Asia, Australia and Europe. A knowledge of the characteristics (both genotypic and phenotypic) of a particular batch of cysts can greatly increase the effectiveness of its usage in a fish or shrimp hatchery.

SIZE AND ENERGY CONTENT

The nutritional effectiveness of a food organism is primarily determined by its ingestibility and, as a consequence, by its size and form (see further: chapter 4.3.3.). Data on biometrics of nauplii from various Artemia strains are given in Table 4.1.2.

Table 4.1.2. Size, individual dry weight and energy content of Artemia instar I nauplii from different cyst sources hatched in standard conditions (35g.l^-1, 25°C)

cyst source	length (mm)	dry weight (µg)	energy content (10-3 Joule)
San Francisco Bay, CA-USA	428	1.63	366
Macau, Brazil	447	1.74	392
Great Salt Lake, UT-USA	486	2.42	541
Shark Bay, Australia	458	2.47	576
Chaplin Lake, Canada	475	2.04	448
Tanggu, Bohai Bay, PR China	515	3.09	681
Aibi Lake, PR China	515	4.55	-
Yuncheng, PR China	460	2.03	-
Lake Urmiah, Iran	497	-	-

Many strains can be differentiated on the basis of their biometrical characteristics. In spite of small variations between batches of the same strain, possibly caused by environmental and/or processing factors, generally the cyst diameter of different production batches of the same strain remains rather constant. Other biometrical characteristics such as cyst volume, cyst dry weight, instar I-naupliar length, individual naupliar weight and naupliar volume, energy content etc., show a high correlation with the cyst diameter. As a consequence, biometrical parameters, in particular cyst diameter, are good tools to characterize Artemia strains, and to help to define the origin of unknown or even mixed cyst samples.

Some general correlations can also be made between sibling species and size: parthenogenetic Artemia produce large cysts, A. tunisiana large cysts with a thick chorion, A. franciscana and A. persimilis small or intermediate cysts with a thin chorion.

HATCHING QUALITY

Comparative studies of the hatching behaviour of cysts of different origin show a considerable variation in hatching percentage, rate and efficiency. However, none of these parameters is strain specific as they are influenced by a wide array of factors like harvesting, processing, storage and hatching techniques, as well as production conditions affecting the parental generation. For optimal use of Artemia in aquaculture the hatching characteristics of any batch of cysts being used should be known. More information in this respect is given in chapter 4.2.5.2.

GROWTH RATE OF NAUPLII

Standard culture tests with brine shrimp from different geographical origin show important differences in growth rate even within the same sibling species, but not among batches of the same strain (Table 4.1.3.). Although in the field the population growth of Artemia (i.e. after inoculation) is determined by lots of factors, selection of a strain with a high potential growth rate will have a positive impact on maximal production output.

TEMPERATURE AND SALINITY TOLERANCE

Both temperature and salinity significantly affect survival and growth, the effect of temperature being more pronounced. A broad range of temperatures and salinities meets the requirements for >90% survival. Strains from thalassohaline biotopes share a common temperature area of preference in the range 20-25°C where mortalities are <10%. Interaction between temperature and salinity is limited; substantial differences in tolerance have been recorded at low salinities (around 5 g.l^-1) and high temperatures (30-34°C). At elevated temperatures the survival of the GSL strain is significantly higher than for other strains.

Table 4.1.3. Growth of Artemia nauplii from different cyst sources under standard culture conditions (7 days, darkness, 10 instar I nauplii/25 ml, 35g.l^-1, 25°C, fed with Dunaliella viridis)

cyst source	growth expressed as % recorded for reference strain (SFB, batch 1)
San Francisco Bay, CA-USA, batch 1	96
San Francisco Bay, CA-USA, batch 2	96
Macau, Brazil, batch 1	98
Macau, Brazil, batch 2	103
Great Salt Lake, UT-USA, batch 1	125
Great Salt Lake, UT-USA, batch 2	127
Shark Bay, Australia	95
Chaplin Lake, Canada	130
Tanggu, Bohai Bay, PR China	110
Aibi Lake, PR China	105
Yuncheng, PR China	109

LIFE HISTORY TRAITS AND REPRODUCTIVE CAPACITY

Life history and reproductive characteristics of Artemia strains are important factors when an introduction of brine shrimp in a new habitat is considered, especially when competition with a local strain is to be expected. These competitive abilities are related to factors like the length of reproductive, pre- and post-reproductive period, total lifespan, number of offspring per brood, broods per female, time in-between broods etc. In general New World (bisexual) populations have a very large number of offspring per brood, a large number of offspring/day/female and a fast development time to sexual maturity, which favours this group to Old World bisexual and parthenogenetic Artemia.

Age at first reproduction is a key factor determining the population growth rate, and the rate of colonisation of new environments with limited nutrient resources. Consequently, if environmental preferences and nutritional factors don’t interfere, New World bisexuals generally outcompete parthenogenetic strains, the latter in their turn predominating over Old World bisexuals. Inoculation experiments in natural habitats therefore require prior screening of candidate strains and of eventual local populations, as well as the study of prevailing environmental conditions. Uncontrolled introduction of Artemia may thus lead to a decrease of natural variability. Therefore, before inoculation of Artemia in a habitat with a local strain is undertaken, sufficient cyst material of the local population must be collected and stored in order to safeguard its gene-pool.

NUTRITIONAL VALUE

In the late seventies, when many fish and shrimp hatcheries started to go commercial, switching from one source of Artemia to another provoked unexpected problems (Table 4.1.4.). Very significant differences in production yields were even obtained with distinct Artemia batches of the same geographical origin. Especially the pattern of total lipids and fatty acid composition, as well as the metabolization of fatty acids in the Artemia, seemed to differ widely from strain to strain, and even from batch to batch, as a consequence of the fluctuations in biochemical composition of the primary producers (mainly unicellular algae) available to the adult population. Cyst products from inland resources are more constant in composition, be it however at suboptimal low levels. Appropriate techniques have thus been developed to improve the lipid profile of deficient Artemia strains, taking advantage of the indiscriminate filter-feeding behaviour of Artemia.

Applying simple methods lipophilic compounds can be easily incorporated into the Artemia before being offered as a prey (see chapter 4.4.).

A number of other compounds also appear to be variable from strain to strain: nutritional components such as total amount of free amino acids, pigments (canthaxanthin), vitamin C, minerals and trace elements, as well as contamination with chemicals such as pesticides and heavy metals. In most cases these variations are not strain specific, but just correspond to different production conditions. Despite this, their effects on larviculture success are usually far less significant.

Table 4.1.4. Growth and survival of fish and crustacean larvae fed with Artemia nauplii from different cyst sources

cyst source	species tested	survival	growth
San Francisco Bay, CA-USA, various batches	Mysidopsis bahia	+	+
	Palaemon serratus	+	+
	Cyprinus caprio	+	+
	Solea solea	+	+
	Scophthalmus maximus	+/±/-	+/±/-
	Dicentrarchus labrax	+	+
Macau, Brazil, various batches	Mysidopsis bahia	+	+
	Cancer irroratus	+	+
	Menidia menidia	+	±
	Cyprinus carpio	+	±
	Scophthalmus maximus	+	+
	Pseudopleuronectes americanus	+	±
Great Salt Lake, UT-USA, various batches	Mysidopsis bahia	+/-	+/-
	Cancer irroratus	-	-
	Palaemon serratus	-	-
	Penaeus vannamei	-	-
	Menidia menidia	+	+
	Cyprinus carpio	+	+
	Dicentrarchus labrax	-	-
Shark Bay, Australia	Mysidopsis bahia	+	+
	Cancer irroratus	+	+
	Menidia menidia	+	+
	Cyprinus carpio	+	+
	Pseudopleuronectes americanus	+	+
Chaplin Lake, Canada	Mysidopsis bahia	±	±
	Menidia menidia	±	-
	Cyprinus carpio	+	-
	Pseudopleuronectes americanus	+	±
	Pagrus major	+	±
Tianjin, Bohai Bay, PR China	Mysidopsis bahia	+	+
	Menidia menidia	+	+
	Cyprinus carpio	+	+
	Pseudopleuronectes americanus	+	+

4.1.3. Literature of interest

Beardmore, J.A., Pilla, E.J., and Thomas, K.M. 1994. Genetic variation in Artemia: speciation, reproductive mode and potential for exploitation. In: Book of abstracts of contributions presented at the International Conference “Improvement of the commercial production of marine aquaculture species”. G. Gajardo and P. Coutteau (Eds), Puerto Montt, Chile, 5-9 December 1994.

Browne, R.A. and Bowen, S.T. 1991. Taxonomy and population genetics of Artemia. In: Artemia Biology. Browne, R.A., P. Sorgeloos and C.N.A. Trotman (Eds), CRC Press, Boca Raton Ann Arbor Boston, USA, pp 221-235.

Browne, R.A. and Halanych, K.M. 1989. Competition between sexual and parthenogenetic Artemia: a re-evaluation (Branchiopoda, Anostraca). Crustaceana, 57(1): 57-71.

Browne, R.A., Li, M., Wanigasekera, G., Simonek, S., Brownlee, D., Eiband, G. and Cowan, J. 1993. Ecological, physiological and genetic divergence of sexual and asexual (diploid and polyploid) brine shrimp (Artemia). Trends in Ecology: 1-14.

Browne, R.A., Sallee, S.E., Grosch, D.S., Segreti, W.O. and Purser, S.M. 1984. Partitioning genetic and environmental components of reproduction and lifespan in Artemia. Ecology, 65(3): 949-960.

Lavens, P. and Sorgeloos, P. 1987. The cryptobiotic state of Artemia cysts, its diapause deactivation and hatching, a review. In: Artemia Research and its Applications, Vol. 3. Sorgeloos, P., D.A. Bengtson, W. Decleir and E. Jaspers (Eds), Universa Press, Wetteren, Belgium, pp 27-63.

Léger, Ph., Bengtson, D.A., Sorgeloos, P., Simpson, K.L. and Beck, A.D. 1987. The nutritional value of Artemia, a review. In: Artemia Research and its Applications, Vol. 3. Sorgeloos, P., D.A. Bengtson, W. Decleir and E. Jaspers (Eds), Universa Press, Wetteren, Belgium, pp 357-372.

Persoone, G. and Sorgeloos, P. 1980. General aspects of the ecology and biogeography of Artemia. In: The brine shrimp Artemia. Vol. 3. Ecology, culturing, use in aquaculture. Persoone, G., P. Sorgeloos, O. Roels and E. Jaspers (Eds), Universa Press, Wetteren, Belgium, pp 3-24.

Pilla, E.J.S and Beardmore, J.A. 1994. Genetic and morphometric differentiation in Old World bisexual species of the brine shrimp (Artemia). Heredity, 72: 47-56.

Tackaert, W. and Sorgeloos, P. 1991. Semi-intensive culturing in fertilized ponds. In: Artemia Biology. Browne, R.A, P. Sorgeloos and C.N.A. Trotman (Eds), CRC Press, Boca Raton Ann Arbor Boston, USA, pp 287-315.

Triantaphyllidis, G.V., Zhang, B., Zhu, L. and Sorgeloos, P. 1994. International Study on Artemia. L. Review of the literature on Artemia from salt lakes in the People’s Republic of China. International Journal of Salt Lake Research, 3:1-12.

Vanhaecke, P., Tackaert, W. and Sorgeloos, P. 1987. The biogeography of Artemia: an updated review. In: Artemia research and its applications. Vol. 1. Morphology, genetics, strain characterisation, toxicology. Sorgeloos, P., D.A. Bengtson, W. Decleir and E. Jaspers (Eds), Universa Press, Wetteren, Belgium, pp 129-155.