Its typical habitat is on rock bottoms with encrusting red algae, Lithophyllum, or soft sediments composed of coarse sand and shell fragments.

[3] In the subtidal zone of temperate Chile it feeds on eight different species of echinoderm, and with Meyenaster gelatinosus is the dominant predator.

[5] Other species of starfish recorded in the same zone in the cold waters off Peru are Patiria chilensis, Stichaster striatus and Meyenaster gelatinosus.

[6] L. magellanica plays an important role in the control of grazing echinoids, and such factors as El Niño events can alter the population dynamics.

If fewer L. magellanica are recruited because of temperature and other factors, more grazers such as Tetrapygus niger survive, and barren areas occur.