May 25th Richard de Hamel

Today we met Brian’s friend, Richard de Hamel. He brought us to this beach when the tide was at its lowest point. We were sent out to explore under rocks and tide pools to see what kinds of different species we could find.

We found many different species of crabs, but we decided to focus on one of the first crabs we found, the Porcelain Crab. The Porcelain Crab is of the family Porcellanidae, this type of crab in unique because instead of using its large front claws to eat it uses its maxillipeds, called setae. Therefore, it is considered a filter feeder and it feeds primarily on plankton but will eat flesh from fish and shrimp. Porcelain Crabs live mainly in rock pools in all oceans except the Arctic and Antarctic Oceans. Porcelain Crabs are also not considered true crabs because they only have three pairs of walking legs compared to four pairs in true crabs.

Another interesting creature that we found in the tide pools is the sea urchin. The sea urchin looks immobile upon first site, but really it can actually move, just very slowly. It moves with adhesive tube feet just like the sea cucumber and sea star. It feeds mostly on algae. The most noticeable feature on the sea urchin is its spines. These are used as a defense mechanism against predators. The spines do not cause serious harm in humans, but we are still glad that we found it before we stepped on it. There were many shells stuck in the spines of the sea urchin that we found, and the spines moved slightly when we pulled the shells away. We learned that sea urchins are even served as a delicacy in some countries, and we would be really interested to try that.

There were many other animals on the beach shore including a hairy legged crab, a sea squirt, and many, many sea stars. The hairy legged crab is distinguished exactly as its name implies, it has hairs on its legs. It is the only crab in the New Zealand area that has that feature. We saw many different species of the sea stars, big and small, under the rocks. By flipping the sea stars on their backs, we could see the tiny tube feet moving. We even saw a sea star that had half ingested a chitin. Most of the creatures were found closer to the water rather than more on shore. This is because they do not have to live in the open air as long as the tide is low. Species that do live more on shore have to have the ability to deal with the changing environment around them such as bird predators, fresh water rain, and low oxygen from water. However, they have far less competitors than species closer to the water.

Overall, Richards’s trip to the beach was a success and we learned much more about ocean species than we ever would in Minnesota.

Jessica and Katie