Octopus mimus, the Changos’ octopus

Octopus mimus is a meroplanktonic species with small planktonic hatchlings (∼3mm total length) and benthic juvenile and adult phases. It is the most abundant octopus species along the west coast of South America, distributed from southern Ecuador to northern Chile. Its embryonic development may last between 25 d (at 24°C) and 65 d (at 16°C), with the apparent lower thermal limit for normal development at around 12°C. There is no information about the settlement or juvenile phases. Subadult growth rates seem to be faster in northern (Peru) than southern (Chile) distribution limits, with females growing equally or more slowly than males, presumably due to sex-related differences associated with reproduction. Size at maturity, however, is greater in females (1000–1200g) than in males (200–400g). Female fecundity is significantly correlated with size. Spawning takes place throughout the year, with a major peak during the austral spring and summer (October–March). Beak growth increment counts suggest a 1-year lifespan, although length-frequency data from wild and laboratory-reared individuals suggest a maximum lifespan of around 2.5–3years. O. mimus is a generalist predator, with crustaceans and molluscs being the most common prey items, but showing some variation depending on geographical zone and season. Instances of aggressive behaviour leading to cannibalism have been recorded in the field and in individuals maintained at high densities in the laboratory. Predators of O. mimus include mammals (the South American sea lion) and coastal fishes. Considering its large distribution range, it is likely that O. mimus plays an important role in coastal food webs. There have been no detailed studies on parasites, but in Chile and Peru, the intestine and caecum are infected by coccidians of the genus Aggregata.