Monday, January 1, 2018

Research @ Otago - Erica Donlon

Erica is studying growth, development rates, and ageing methods in the midget octopus, Octopus huttoni.

Erica taking measurements of a common octopus

Erica is currently breeding wild caught midget octopus from Otago and the Foveaux Strait. Once females lay their eggs in a small crevice or tube, they will starve for the entire gestation period (30-80 days) in order to protect the eggs and keep them clean of debris.

Midget octopus with eggs
When the eggs hatch, the paralarvae live in the plankton for 40-70 days feeding on crab larvae and absorbing nutrients through the skin. In Erica's experiment, the paralarvae will be reared in 4 temperatures (5°, 11°, 17°, and 23°C) to observe how ocean warming could have an effect on the developmental rates of these octopus.

Midget octopus paralarvae
The white ball seen beneath the eyes and between the tentacles is a yolk sac that will be quickly consumed as they start swimming in the water column.

Paralarvae starting to hatch
During the next year, Erica will be observing the growth rates of this species by looking at growth rings on the beaks and stylets (remnant of the mollusc shell). This new information will give more insight of the life history of this species which can then be applied to other pygmy octopus species.

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