Attack of the Giant Green Anemone!

This could be a somewhat believable title for a cheesy horror movie. After all, Giant Green Anemones are carnivorous. Not to worry! The sting is harmless to humans.

These beautiful flower-shaped creatures feed on small fish, newly molted crabs, sea urchins, detached mussels, and bits of marine plants. Some fish have developed protection against the anemone’s sting by covering themselves with mucus.

Little Giants

Even though Giant Green Anemones carry the name ‘Giant’ most only measure between seven and 12-inches.

They live a solitary life, and sometimes congregate in small groups (less than 14). These small groups create what looks to be a beautiful underwater floral arrangement. They will change color depending on the amount of light they receive. Different types of anemones will have other colors.

A Deadly Crown

Giant Green Anemones sport an oval crown of six or more rows of tentacles. These tentacles have stinging cells that help protect the anemone from predators. The tentacles also stun prey and help pull the prey into the anemone’s mouth.

Predators include seastars, snails, sea spiders, and fish. Some predators feed on the tentacles and others feed on the column.

Finding Them

Giant Green Anemones stay in the same location most of their lives. They can slowly walk around and swim to escape predators or when detached. These little giants are found in intertidal zones from Alaska south potentially as far as Panama.

Intertidal zones are areas that are above the water level during low tide. Anemones prefer areas where water is present most of the day such as tidepools and relatively shallow harbors.

Low tide will sometimes expose Anemones clinging to pilings and rocks, or even on the beach. When exposed, the anemone will ‘droop’ or close up into its green and brown stem while waiting for the incoming tide.

The fragile, yet harsh Intertidal zones are a challenging place to live but does provide some predation protection. Water conditions can be challenging. While the tide is regular, the shore may not pool the water. The water may be salty one day and diluted by fresh rain the next, and hard wave action can carry one out to sea. Still, many species, like the Giant Green Anemone, thrive there.

Amazing Factoid: A compound from the Giant Green Anemone is used by the pharmaceutical industry to create a beneficial heart stimulant for humans.

REFERENCES:
–Wikipedia Anthopleura xanthogrammica and Intertidal zones (https://en.wikipedia.org/wiki/Anthopleura_xanthogrammica)
–About Giant Green Anemone, Monterey Bay Aquarium (https://www.montereybayaquarium.org/animals/animals-a-to-z/giant-green-anemone)