Life in the tidepools


I promised a collection of pictures from our beachcombing adventures in Haida Gwai, and here they are. We were struck by the variation between different beaches, in terms of the plant life (different types of seaweed, seagrasses, etc) as well as the types of shore line (from volcanic rock to sandy beaches), but also by the difference in sea life between our two visits there. Last year we were on the islands in June, and this year in August. Last year we found an abundance of huge moon snail shells as well as evidence of many clams (shells, spouting water when we jumped on the beaches in certain places). This year, we found out that moon snails (which bore holes through clam shells with their noses and then suck out the innards) are only around primarily in the winter season. We looked much more closely at the tidepools this year, and were surprised to find so much more life than we had previously seen.

We found distinct areas of the beach where certain creatures would live together. If we found a starfish in a pool, for example, there were bound to be many more starfish nearby. A sand dollar found meant there were most likely hundreds more slightly dug under the sand and many scattered on the beach nearby. I was walking through a tide pool at one point and heard a scuttling behind me and looked back to see five large pink crabs scurrying in different directions. I think it would be incredible to live in such a place where the shifts and changes of the seasons and ocean would always be bringing newness to your view. Everytime the tide goes in or out, the landscape is changed just a little bit.

The underside of a sand dollar. I had previously only seen dead, dried sand dollars, which are bleached white by the sun and have lovely designs on the tops that resemble poinsettas. These were always my favourite shells to find as a kid. Live sand dollars are actually a vibrant purplish-red, and have thousands of tiny cilia protruding from their bottom sides. They sit vertically in the sand and syphon tiny particles of food from the water around them using these wee tentacle arms. When you pick them up, all of the cilia stop moving until they relax again and slowly start to wiggle.

The purple round things in the stream of descending tide are live sand dollars.

A starfish with 13 arms. This guy was incredibly slimy, and slowly slithered his way off my hand as we were taking the picture. Again, with hundreds of tentacles on the bottom of it’s body, it was a really weird feeling to hold this one and feel it slime it’s way off with it’s arms curling towards the ground.

The same starfish looks alot prettier when it’s in it’s natural habitat.  (the following bit of info is shamelessly copied directly from wikipedia). I found the information fascinating.

There are about 1,800 living species of starfish that occur in all the world’s oceans, including the AtlanticPacific,Indian as well as in the Arctic and the Southern Ocean (i.e., Antarctic) regions.

Starfish are among the most familiar of marine animals and possess a number of widely known traits, such asregeneration and feeding on mussels. Starfish possess a wide diversity of body forms and feeding methods.

Most starfish typically have five rays or arms, which radiate from a central disk. However, several species frequently have six or more arms. Several asteroid groups, such as the Solasteridae, have 10-15 arms whereas some species, such as the Antarctic Labidiaster annulatus can have up to 50. It is not unusual for species that typically have five-rays to exceptionally possess six or more rays due to developmental abnormalities.

This is just the beginning of the information on these interesting creatures that can grow up to two feet wide and live up to 34 years old.  They were by far our favourite discoveries in the tidepools.

A collection of carpet starfish. These come in a variety of vivid colors.

A close up of an orange carpet star.

The underbelly of a carpet starfish. The jelly looking thing in the middle is it’s stomach/mouth. Some starfish will actually begin to digest molluscs outside of their bodies with their mouths until the mollusc can be drawn into the starfish body. The bottom of the starfish is covered in tiny little arms with suction cups on the ends of them which cling to rocks and other debris (the black things on the bottom)

A five armed starfish. The biggest one of these we found was about 18 inches across.

A large crab, mad at us because we moved the smaller dead crab that it had between it’s claws to get a better look. These guys are scavengers, eating anything they can find, including other crab.

The reason you don’t touch these guys with your fingers. They are really quick, and quite protective. You also wouldn’t want to walk into one of these with bare toes.

A closed up sea anemone. One pool we found had close to 30 sea anemones of all sizes in it. They were this vibrant pink colour, and when relaxed have many tiny arms that drift in the water. They are beautiful. If you touch them, they quickly pull all of their arms in tight and close into a harder ball shape. We watched them at times suck themselves right into the sand so that they were practically invisible.

I can’t remember the name of this creature, although we found it in an ocean book last year and I’m pretty sure it is one of the oldest living beings (from long, long, ago.) on the planet. It was really firmly attached to this rock.
Hope you enjoyed your virtual tour of the sandy shore of Sandspit.

One response »

  1. LOVED this post. I am crazy for tidepool life and had some marvelous times this summer discovering different creatures, on my own and with my kids. That last one is a Chiton (not sure the exact type). Was it turquoise on the underside? I found a turquoise underneath one this summer, it was so beautiful. My friend Claire is trying to convince us to go to Haida Gwaii next summer… Your photos are helping. I don’t think our family is ready for the trek yet… someday though!!

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