- Characteristics of Artemia salina
- Morphology
- Head
- Chest
- Abdomen
- Taxonomy
- Habitat and distribution
- Lifecycle
- Nauplius
- Metanauplius
- Pre - adult
- Adult
- Culture
- Getting cysts
- Decapsulation of cysts
- Hatching
- Development
- Feeding
- References
Artemia salina is an arthropod that belongs to the group of crustaceans. It is characterized by being very small (up to 10 mm) and inhabiting continental brackish water bodies. Very rarely it is found in oceans or seas.
This crustacean is an important part of zooplankton, which is why it is a main source of food for other animals such as fish. Likewise, Artemia salina is used for aquaculture, so its cultivation is a very frequent activity. Its cultivation is simple and does not require very sophisticated tools or equipment.
Specimens of Artemia salina. Source: © Hans Hillewaert
Characteristics of Artemia salina
Atemia salina is an organism that, like all members of the animalia kingdom, are multicellular eukaryotes. In their cells, which are specialized in various functions, they have a cell nucleus where DNA is stored.
Likewise, this crustacean is considered a triblastic organism with bilateral symmetry. In this sense, when the animal is developing it has three germ layers, whose cells give rise to all the organs of the adult individual.
They are animals that are distributed throughout the world, thanks to their ability to colonize ecosystems with various characteristics in terms of temperature and salinity.
In these animals, there is mainly a sexual reproduction, with internal fertilization and indirect development.
Morphology
Artemia salina is a small animal, reaching an approximate length of 10 mm.
As with all arthropods, its body is divided into several segments: head, thorax and abdomen.
Head
It is made up of the fusion of five segments. On both sides are the organs of vision, which are represented by compound-type eyes.
Likewise, on the head there are also appendages known as antennae. In the case of males, the antennae are shaped like pincers or pincers, while in females the antennae are shaped like leaves.
Other appendages seen on the head are the jaws and maxillae, which are used by the animal in its feeding process. Also present on the head is a pair of very small antennae, the secondary antennae.
Chest
The thorax is divided into a total of eleven segments. From each segment a pair of appendages emerges that are known as thoracopods. The function of these appendages is related to the movement of the animal.
Abdomen
It is the thinnest area of the animal's body. It is divided into eight segments. The first segments are the genitals. In the case of females, a widening can be observed, known as the ovigerous sac, which communicates with the outside through the genital pore.
Female and male Artemia salina specimens. Note the ovigerous sac in the female. Source: K.Tapdıqova / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
Taxonomy
The taxonomic classification of Artemia salina is as follows:
- Domain: Eukarya
- Animalia Kingdom
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Branchiopoda
- Order: Anostraca
- Family: Artemiidae
- Genus: Artemia
- Species: Artemia salina
Habitat and distribution
Of all the species of the Artemia genus, Artemia salina is the one that is most widespread throughout the planet. They are particularly abundant in North America, central Asia, Australia, southern Spain, and Tunisia.
Contrary to what one might think, Artemia salina is not typical of oceans or seas, but is found in bodies of water such as lakes and lagoons. Because this crustacean has an internal system that helps regulate osmotic pressure, they can develop in places where there is high salinity.
Lifecycle
The type of reproduction observed in Artemia salina is sexual. This involves the fusion of female and male gametes (sex cells). Fertilization is internal and development is largely determined by salinity conditions. When it is very high, development is ovoviviparous, while when conditions are normal and stable, the animal behaves like viviparous.
Now, the development of this crustacean is indirect, since they present intermediate stages between the egg and the adult individual. In this sense, the life cycle of Artemia salina includes several stages: nauplii, metanauplii, pre-adult and adult.
Nauplius
It is the first larval stage. It is characterized by being orange in color and measuring approximately 250 microns. In addition to this, the body is not segmented. Some specialists maintain that there are two types of nauplii: Nauplius 1 and Nauplius 2.
As a whole, this larval stage lasts approximately 30 hours.
Metanauplius
It is a second larval stage. The main characteristic of the metanauplii is the presence of the thoracopods. These are nothing more than appendages that are detached from its body and that, later, participate in the locomotion of the animal. As expected, the size in this phase increases significantly.
Pre - adult
At this stage, the different characteristics that will identify males and females begin to appear. The main differential character that appears in this stage has to do with the morphology of the antennas. In females they are very small, while in males they are larger and pincer-shaped.
Adult
Already in this phase the animal acquires its definitive characteristics.
Culture
The cultivation of Artemia salina is a fairly common and important activity in the aquaculture industry. In this sense, the cultivation of this crustacean is a simple process that, despite being made up of several stages, is not very difficult.
Getting cysts
The first step to start the culture of Artemia salina is to look for the eggs. However, they are abundant in tropical and subtropical areas, specifically on the shores of large bodies of water such as streams and lakes.
Eggs are also marketed, so they can be purchased this way as well.
However, when the eggs are obtained naturally, they are usually found in the form of cysts. Once collected, these must undergo a somewhat complex process. They must be passed through a sieve and washed, both with seawater and with fresh water. This is done in order to remove cysts that are not viable.
Decapsulation of cysts
The next step is to decapsulate the cysts so that they can hatch. For this reason it is necessary to follow some procedures, such as hydrating the egg for a certain amount of time.
Subsequently, the eggs considered viable are subjected to the action of a decapsulant solution for approximately 7 minutes. They are then washed, first with tap water and then with a hydrochloric acid solution with a concentration of 1 Normal.
Finally the eggs are transferred to an incubator with sea water and are left there waiting for them to hatch and for the larvae to emerge.
Hatching
In order for the eggs to hatch and the larvae to be released, certain environmental conditions must exist. First, the temperature must be between 25 ° C and 30 ° C. Likewise, the pH must be at 8 and there must also be a wide availability of oxygen, since this is a relevant element in the development of this organism.
Development
While waiting for the larvae (naupilos) to transform into adults, what must be done is to transport them to an aquarium, where the appropriate lighting, temperature and salinity conditions must be maintained.
As time passes, the larvae develop, until they reach the stage of adulthood. After about two weeks, the first matings begin to occur, and consequently the population of Artemia salina begins to grow.
Feeding
Artemia salina is an organism that feeds through a filtration process. That is, they feed on suspended particles that together make up the phytoplankton. It is important to note that Artemia salina is constantly fed, since it does not feed at a specific time of the day, but does so 24 hours a day.
When this crustacean is cultivated, you can buy an extract that contains phytoplankton in suspension, in addition to yeast.
It is important to emphasize that for the culture of Artemia salina to be successful and profitable, it is important to monitor and maintain the ideal environmental conditions, such as salinity, pH and temperature, among others.
References
- Abatzopolulos T., Beardmore, J., Clegg, J and Sorgeloos, P. (2010). Artemia. Basic and appliedd biology. Kluwer Academic Publishers.
- Brusca, RC & Brusca, GJ, (2005). Invertebrates, 2nd edition. McGraw-Hill-Interamericana, Madrid
- Curtis, H., Barnes, S., Schneck, A. and Massarini, A. (2008). Biology. Editorial Médica Panamericana. 7th edition.
- Dumitrascu, M. (2011). Artemia salina. Balneo- Research Journal. 2 (4).
- Hickman, CP, Roberts, LS, Larson, A., Ober, WC, & Garrison, C. (2001). Integrated principles of zoology (Vol. 15). McGraw-Hill.
- Villamar, C. (2011). Artemia salina and its importance in the shrimp industry. Aquatic Magazine. eleven.