The last time I explored tide pools on the Boston Harbor Islands, I was taking Bruce Berman’s Snails to Whales class. We learned the geography of the Harbor, visited the islands, learned about the clean-up, and saw so many creatures I never knew existed in this area. We saw a few of those same creatures on Spectacle Island this past Monday.
Taking cover near a rock, this Asian shore crab (Hemigrapsus sanguineus) does its best to remain hidden. This non-native crab can be distinguished from others in our area by the three “teeth” it has running down each side of its shell. Other species have at least five.
We surprised another one of these crabs and it stood upright on its back legs, its claws pointed up at us. The red spots on its claws are also characteristic of this species.
Common periwinkles (Littorina littorea) shared the rocks with northern rock barnacles (Semibalanus balanoides).
Long-clawed hermit crabs (Pagurus longicarpus) scurried about in their shells, formerly occupied by periwinkles. This one appears to be feeding on seaweed or tiny creatures on the seaweed.
We picked one up and placed it on a rock, waiting for it to emerge from its shell. Its face is a cross between a robot and a gremlin. One claw is much larger than the other.
Rock weed was the most identifiable seaweed growing on the rocks. Turns out this is Irish Moss, a kind of red algae.
We found orange sheath tunicate (Botrylloides violaceus) growing on the underside of the rocks, where it is constantly bathed in seawater. Each orange speck is its own creature, growing in a colony.
Can you find the creature in the photo below?
It’s a transparent shrimp! We saw a couple of these shrimp floating in the tide pools.
A dead skate had washed ashore. The underside looks like a mask from the movie Scream.
Areas of salt water ran down patches of sand, creating these shallow channels.
The tide pools we found were on the southeast corner of the island. Make sure you visit during low tide!