Définition : Active swimming organisms that live in the water column and are able to move independently of the water mass (adapted from Lincoln et al., 1998).
Définition : An organism that moves through the water column via movements of its fins, legs or appendages, via undulatory movements of the body or via jet propulsion; includes pelagic phases during reproduction (swarming at the surface)
Définition : An organism that moves through the water column via movements of its fins, legs or appendages, via undulatory movements of the body or via jet propulsion; includes pelagic phases during reproduction (swarming at the surface)
Définition : Eye-spots which may be set into a pit to reduce the angles of light that enters, to allow the organism to deduce the angle of incoming light. Lens-like structures may be present, but stemmata, unlike lens eyes, cannot form an image, either for lack of refractive power or retinal resolution.