Monday, August 2, 2010

Harbor Class Lovells Island Ted Williamson


Day 3 in the field (trip to Lovells Island) was another beautiful day! 85 degrees, sunny and low humidity. I have been very impressed by the beauty of the Harbor! We identified more harbor islands, including Spectacle Island, Peddocks Island, Georges Island and Rainsford Island a/k/a Shutter Island.

(picture of Rainsford Island)
We pulled into Lovells Island, a 51-acre island, located just north of Georges Island.

It was low tide and we had the opportunity to explore the entire intertidal zone.

We hit the tidepools (always wet) and immediately saw signs of life.

The rocks looked small, but the habitat is huge for the animals we discoved. This is a crab's eye view as I snapped a picture from the shoreline.

We found and captured many animals.

A baby Northern Lobster (Audubon Field Guide)

A Green Crab (Audubon Field Guide)

Sand Lance (Encyclopædia Britannica)

Saltmarsh Snail Shell or a Mottled Dog Whelk (not a large Periwinkle Shell) (Audubon Field Guide)

Small Scallop Shell (Personal Knowledge)

Many different Tunicates

We also discoverd many other animals, including:

  • New arrival (400 years) Rough Periwinkes (Audubon Field Guide)
  • Long-clawed Hermit Crabs (Audubon Field Guide), some found homes in the shells of Periwinkles and smaller ones found homes in Auger shells (Audubon Field Guide)
  • Bruce and another student found and ate a raw Slipper Snail!
  • Sea Squirts
  • Many differnt plants, including Rockweed and sea lettuce

After lunch we looked at shells that had holes drilled into them. What made the holes?

A Whelk made the holes. This is a term used to identify many types of middle-sized snails. Along with eating algea, snails eat shellfish using thier Radula "teeth". (Britannica)

We then went to land and discovered invasive land snails - Grove Snail (confimed Mr. Brennan's assumption by Wikipedia)

How are air-breathing Grove Snails different from sea snails?

Grove Snail characteristics: Based on "Land Snails of New England" by S. Morse

  • Breath air through right side of body
  • Need moisture
  • Have foot to move and antenae for senses
  • No ability to leave shell (tied to it by muscles)
  • Hybernates when needed
  • Can regenerate lost parts
  • Lays approx. 100 eggs based on how their habitat can protect them
  • Has many teeth

Periwinkle characteristics based on: European Invaders: Periwinkles

  • Breath under water
  • Active all year
  • Lays 10,000 to 100,000 eggs
  • Also eats invertabrates (clams, oysters, etc.)

Saturday's and Sunday's habitats had similarities:

  • Both Boston Harbor shorelines
  • Similar climate

But the habitats had more differences:

  • Different depths
  • One had a vertical tide, and the other had a horizontal tide
  • Less interaction with human life at Lovells
  • No shrimp or micro animals found in Lovells' tide pools?



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