Anatomy

Animal science

Circumference

Organic chemistry

Chemistry

Geometry

Hatching

Artemia salina

Toxicity

Mathematics

Biology

Aquaculture

Prior to hydration, the cysts of Artemia salina are cup-shaped with a diameter of approximately 0.18 mm. Upon immersion in sea water, the cysts slightly increase in diameter to 0.19 mm and assume a spherical shape. Hatching begins with the splitting of the surface coat. The split runs along a straight line, approximately one-half the circumference of the cyst. The exposed fracture in the surface coat reveals three distinct regions: (1) a thin (1.2 μm) smooth outer layer; (2) a thick (4.7 μm) ‘spongy’ layer; and (3) a thin (1.8 μm) fibrous inner layer. The split becomes more pronounced as the nauplius, enclosed within a transparent hatching membrane, slowly emerges. Once completely emerged from the cyst, the nauplius begins a series of beating movements which rupture the hatching membrane, allowing the nauplius to swim free.

Hatching events in the cysts of Artemia salina