Verrill’s Two-spot Octopus, Octopus bimaculatus

Verrill’s Two-spot Octopus, Octopus bimaculatus. Octopus collected within Magdalena Bay, Baja California Sur, October 2018. Length: 25 cm (9.8 inches). Catch and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny:  Verrill’s Two-spot Octopus, Octopus bimaculatus (Verrill, 1883), is a member of the Octopodidae Family of Benthic Octopus. The Genus Octopus is one of twenty-three genera in this Family, and there are seventy-three species in this genus. In Mexico this species is known as pulpo manchado.

Morphology:  Verrill’s Two-spot Octopus is a mid-sized octopus that reaches a maximum length of 61 cm (24 inches). Their arms are four or five times the length of the mantle. They are highly variable in color. They are normally mottled in appearance and may be light brown, reddish-brown, gray or yellow-green. They have two dark ocelli (fake eye spots) on their mantle that are found beneath their real eyes and between the second and third arms. The ocelli turn bright blue with broken chain-links when the octopus becomes alarmed or agitated. Their skin is warty in texture, more so than other Mexican octopuses. Verrill’s Two-spot Octopus is very similar to and most likely to be confused with the California Two-spot Octopus, Octopus bimaculoides (found only north of Ensenada, Baja California; eye-spots with unbroken chain links) and Hubbs’ Octopus, Octopus hubbsorium (lack the two prominent ocelli spots).

Habitat and Distribution:  Verrill’s Two-spot Octopus is found over and within rocky substrate in the intertidal zone to depths up to 55 m (180 feet). Verrill’s Two-spot Octopus is a resident of all Mexican waters of the Pacific Ocean.

Diet: Verrill’s Two-spot Octopuses are opportunistic night-time predators that feed primarily on bivalves, crustaceans and gastropods.

Predators:  Verrill’s Two-spot Octopuses are eaten by sharks, moray eels, harbor seals, and sea lions.

Reproduction:  Verrill’s Two-spot Octopuses are gonochoric ( male or female for life). Reproduction is sexual with internal fertilization. In the male of this species one arm is modified to carry sperm in an open groove on the ventral edge. This arm is known as a hectocotylus, and in this Family, is not detachable. The male inserts this arm under the mantle of the female during reproduction, delivering packets of sperm (spermatophores). After fertilization, the female will create a den and seal herself in to lay her eggs. A single female can lay thousands of eggs. She will care for her eggs by blowing cool water over them from her siphon to keep them oxygenated. During the process of caring for her eggs, the female often expires due to starvation and exhaustion. After the eggs hatch, which may take 150 to 210 days, the mother will leave the den if she survives and the larval octopus will drift with the tide before settling on the ground to begin developing. On average, these octopuses produce 70,000 offspring. They mate only once in their twelve to eighteen month life span.

Ecosystem Interactions:  Verrill’s Two-spot Octopuses host ectoparasitic flagellates and ciliate protozoans, which live on the octopus’ gills.

Human Interactions:  Verrill’s Two-spot Octopuses are one of the more abundant species of larger octopuses found in Mexican waters and are fished commercially. Overfishing can cause localized population collapses. From a conservation perspective Verrill’s Two-spot Octopus is currently considered to be of Least Concern with stable widely distributed populations.