Tuesday, August 5, 2008

Tide pools and Land Snails

First I promised to post my picture with my life time fish. I caught this off of Orleans down the cape.

Lovells Island reflection

I really enjoyed the day. The first tide pool we visited was on the west side of the Island and I was able to observe the sea life that was entrenched under the rocks in the tidal pool. When we displace a few rocks we could see crabs the size of a quarter scurrying about. The crabs were of a brownish gray color and were very quick. I tried to pick the crab up to take a picture of it but it was very agile. The crab kept scurrying from one rock to another. I believe that this behavior would be beneficial in trying to stay alive when sea gulls and other bird life are feeding. Instinctively the crab found shelter under the edge of the rocks in the tidal pool.

We then moved on to the north side of the island to another good spot to observe the sea life living in the tide pool. I watched very carefully as the periwinkle snails seemed to move across the rocks on top of the rocks surface. I was surprised at just how fast they moved. I was also surprised that when I pulled at the periwinkle; to get a closer look I could actually feel the suction from below. The periwinkles I observed were black in color and had an opening at the bottom. I subsequently learned they use this trap door like opening to help against predators, and to keep in moisture and water so they can survive during the changes in tide and in tide level.

A key observation for me was how the see grass and other sea life seemed to be gathered toward the northwest side of the Island. As the pictures show above the further you see to the east the less accumulation on the shore. I believe that this occurs due to the currents of the ocean, the direction of the wind and the man made rock erosion barriers that form a jetty at the tip of the tide pool.

One question that I pondered is what impact does the man made structure have to the types of life that exists.

My speculation is that it does have an impact. Without it there would be no place for the lava to be stopped to start the life process and the life form may end up dying as it continued to float across the ocean.

Land Snails

My group observed a number of residual snail shells and collected the rarest shell which was the all yellow sample. When I picked it up I thought it was special. My first thought was that it was just worn out from being blown against the ground over a long period of time. My second thought was that it may have picked up some coloring from the plant life in the area where I found it. After our careful review I think that this snails shell was the true color and most probably used as camouflage for protection against birds.

We started at the top of the islands hill and did not have much success finding living snails. We realized that we were in the highest altitude and decided to go lower. We did have success finding living snails. We found them living in the lowest potions of the island upside down on the bottom side of leaves.

We discussed Three types of snails

Common in water


On shore living in mist

Mystery snails have both lungs and snails

We gathered all the shells approx 100 by and sorted them by color size and body style. The question we pondered was is this one species or many? Based on our evaluation I believe that the group felt it was actually one species but with many variations in shell coloring.

Watching the living snails eat the leafs and leave their droppings was also interesting.

Cute little fellas


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