How is abalone restoration affected by octopuses?

Octopuses are formidable predators, and they love to eat little abalone. 

Efforts to restore the endangered white abalone may depend in part on how much scientists can learn about one of its natural predators, the California two-spot octopus. Full story:

Population Surveys and Octopus Collection

Our first step is establishing how many octopuses are in our sites, and where they are located. 

How to catch an octopus 

I catch octopuses using vinegar (CDFW Scientific Collection Permit #11725). It takes patience and a little trickery. 

How to tag an octopus

This is Octopus H, so we named her Hermione! She was tagged off the coast of San Diego, CA as part of my study understanding octopus movement, habitat use, and habitat choice. 

How does VPS (Vemvo Positioning System) work?

Determining the position of a tagged octopus is very similar to the way Google knows where you are. When at least three of my stationary receivers (the black bottle shapes in the animation) detect the coded sound, or "ping" that is emitted from the octopus tag, we can use the slight differences in the amount of time it took that ping to reach each receiver to calculate the octopus's position. This is called triangulation. 

This work is funded by the California Sea Grant.


Measuring and Tagging

Every octopus that is caught is measured, weighed and, sexed. See the image below to learn how to tell the sex of an octopus!

how to sex an octopus.jpeg

Each octopus arm is numbered. If you orient the animal so the eyes are on top, the arms on the left side of the body are L1 through L4, and the arms on the right side of the body are R1 through R4. In females, all arms look the same. In males, R3 is a modified sex arm, called the hectocotylus. There is typically a groove down the side of the arm (the "sperm conveyor belt") and a the tip of the arm has a species-specific morphology, called the ligula.  During reproduction, the male octopuses inserts this arm into the oviduct of the female.