Chilean Sea Urchin, Loxechinus albus

Image Caption: Chilean Sea Urchin, Loxechinus albus. Credit: Dentren/Wikipedia (CC BY-SA 3.0)

The Chilean sea urchin (Loxechinus albus) is a species that can be found along the coastlines of Chile and Peru. It is typically found in shallow waters at or below the tide level, buried in sand or lying just on top of it. This species is often associated with Macrocystis pyrifera, a type of kelp. It is most often found in more open spaces.

The Chilean sea urchin can reach an average width of up to 3.9 inches. This species has a test shell that is covered completely in spines, and it holds between six and eleven ambulacral plates that bear primary and secondary spines. It is typically green in color, with reddish interambulacres and ambulacres, and some larger individuals found in deeper waters can be white in color.

The Chilean sea urchin spawns at different times depending upon its location, either in June or between November and December. Individuals found in the Magellan Region deviate from this, typically spawning between June and September. After the larvae are spawned, they remain in the zooplankton for about thirty days, feeding on phytoplankton until they are large enough to fall to sea floor. The larvae reside in the intertidal zone within crevices until undergoing metamorphosis, at which point they move into areas that are more open.

The Chilean sea urchin is an herbivore, feeding on many species of algae that live alongside it. Young members of this species feed primarily on algal detritus, crustose coralline algae, and diatoms. Unlike sea urchins found in the Northern Hemisphere, this species does not appear to be limited by the amount of algae found in its area, because there are no population swings or barren areas, which are made by large numbers of sea urchins stripping the sea floor of algae. It is thought that this occurs because the species feeds on floating algae as well as algae found on the floor.

In Chile, the Chilean sea urchin is locally known as Erizo rojo, which mean red urchin. It is harvested in this area to be used in local cooking, but this practice is causing the species to become rare in certain places. There are no regulations that control the harvest of the species, and it takes at least eight years for some populations to return to normal, harvestable levels.