JJJ Family: Tidepools at Leo Carrillo (1/25/09)

The day before Chinese New Year, we enjoyed a blissful afternoon in Leo Carrillo State Park, visited the tidepools during the lowest tides, and spent a very educational hour with a lovely attentive docent... We always have fun in the tidepools, but never really knew too much about the habitats. It was quite nice to come across this opportunity to explore the tidepools with some knowledgeable naturalists. Such public program is sponsored by Malibu Sector Interpretation of California State Park. For details, please visit http://www.malibuinterp.com/

Among some fascinating tidepools facts and creatures that we learned, the most memorable animal that we encountered was a sea hare (i.e. a very large sea slug). Its primary food source is algae. When disturbed, the sea hare will extrude a bright purple fluid (which is derived from the algae it eats) to distract the attention and escape from danger. Unfortunately, Joshua had some potato chips after he played with the sea hare using his fingers, and came back home with a very sick stomach.

We spotted quite a number of knobby sea stars, mostly chocolate chip color and a few orange ones we spotted on occasionally. When they eat, they use their extremely strong tube feet to pull open their bivalves and then digest their prey outside of their bodies. We were all amazed by the amount of force a relatively small sea star can produce by adjusting the water pressure inside its body.

Aside from hermit crabs, another common animal found in the tidepools is green sea anemone. Green sea anemone is related to jellyfish and corals because it has stinging cells which paralyze and digest its prey with ease. Unlike jellyfish, the stinging cells of a green sea anemone are too small to penetrate human skin.

We learned about “zoning”. Some animals can only survive where the waves pound the rocks, others need the relative shelter of deeper water. Plants and animals can dry out if exposed for too long at low tide.

We sighted a few Chitons and learned that Chiton is a type of mollusk that identified by eight shell plates held together by an outside oval of tissue.

We got to visit the coastal cave which only accessible during the lowest tides. Inside the cave, we sighted groups of gooseneck barnacles. In the earlier days, gooseneck barnacles were confused as birds, since the similarities in color and shape.

Another startling animal we learned is sandcastle worms (or we like to call them beehive/ honeycomb sand worms). Sandcastle worms build sturdy tube-shaped homes from bits of sand and shell, shell, and their own natural glue. Their homes are hard to the touch at first, but with a little force, our fingers can crash their homes at ease.

It may look like a still-life painting at low tide. When nothing seems to be moving, but plant and animal inhabitants interact and affect each other in many ways. There is keen competition for space, light and food. There is predation, one animal eating another. There are animals depend on others (e.g. neighbors) to survive, but some are better off to live alone than in groups. There are animals living on other animals and even inside other animals!