Thursday, July 26, 2012

Snails and Lovells Island

Today we explored the tidal pools at Lovells Island.  We almost weren't able to due to a cancelled boat, but the wonderful crew of the Abigail helped us out in our time of need.  Thank you again!

On Lovells Island, the tide pools were teeming with life.  We found so much!  We had hermit crabs, sea lettuce, rockweeds, barnacles, green-grass like seaweed, blue mussels, asian shore crabs, tiny arthropods, periwinkes and tunicates galore!  The tidal pools had organisms from both environments.  The growth of the seaweed and organisms wasn't as dense as we found in the subtidal locations at the Barking Crab and Rowe's Wharf, but it was much more dense than the periwinkles and crabs found at Peddock's Island.  
 Life in the tidal pool

Personally, I was surprised by the amount and variation of tunicates we found.  We found orange sheath tunicates, blood tunicates, a colony of tunicates, and another lighter colored tunicate. 
 Blood tunicate
 Colony of tunicates
Orange sheath tunicates and another tunicate

We also saw several periwinkles.  Here's a picture of three different ones.
The orange shell is most likely a smooth perwinkle.  According to Peterson's Field Guide, the smooth periwinkle is small and round, and lives among the rockweeds.  The spire is low, and the whorls are smooth.  The color varies and includes orange.  I believe the other two are rough periwinkles.  The rough periwinkles vary in color including white and brown, have a longer and more oval-ish shape than the rounded common periwinkles and has the deeper groove pattern on the shell.  We also saw many common periwinkles.

We also saw some terrestrial snails.  On the beach there was a grouping of shells on the rocks, and then we found live snails on the trees.
Empty snail shells on the rock on the beach

Live terrestrial snail
As far as what type of snail it is, I would say this is a white lipped snail.  The coloring varies with the white lipped snail, but the lip is generally white or light colored as it is in this case.  The bands of color are common with the species, and the snails are able to withstand a wetter climate.  (http://www.arkive.org/white-lipped-banded-snail/cepaea-hortensis/#text=Description and http://www.naturespot.org.uk/species/white-lipped-snail)

As for how the shells got to the rock, I would say that seagulls brought them there.  There were wide holes in each of the shells that make it appear that they have been damaged, and I would venture a guess that a seagull brought them over to the rock and hit them with its beak until it was able to eat them.  Here's a video on how seagulls eat snails: http://video.nationalgeographic.com/video/kids/animals-pets-kids/birds-kids/seagull-eating-snails-kids/.

See you all tomorrow!
-Danielle

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