Wednesday, June 13, 2007

The Otter Trawl

An otter trawl is one of the best ways to get an up-close look at the diversity of creatures that live in Narragansett Bay. Today, 20 seventh graders from Thompson Middle School in Newport came out on the Bay aboard Save The Bay’s vessel Alletta Morris, and helped Captain Eric and the crew — me and Bekah — to haul the trawl net aboard near Potter’s Cove, off Jamestown.



The students were hooting and hollering as they pulled the lines in, hand over hand. But Bekah, Eric and I were exchanging worried glances because the net didn’t feel quite right — it was resisting our pull, more than usual.

“You’re almost there, guys, just a little further!” Bekah said.


As the otter boards broke the surface, Captain Eric said, “Stop! Drop the line!” He grabbed one otter board and I grabbed the other. We knew Potter’s Cove usually provides a good catch, so we hoped for a full cod-end. When we got the net on board, we found a big round bulge, and the explanation for all that weight. “A tire!” Captain Eric said.

Despite the tire, we still managed to get a decent catch for such a chilly spring. Narragansett Bay is several degrees colder right now than it was at this time last year. After untying the fishermen’s knot at the cod-end, we opened the bag up wide, and wriggled the tire out to find a 12” winter flounder very happy to flop into the water benches we had filled up with Bay water. Also sharing the cod-end of the net were dozens of sea stars, a few spider crabs, a squid that was a little over a foot long, a few hermit crabs, and a channeled whelk.




Our crew cleared the net, got the lines out of the way, and invited the very excited students to the benches in the back of the boat to examine their catch. After hearing about how sea stars have an eye on the tip of each of their legs, and that it isn’t good for fish to be touched too much because of their protective slime coating, a few of the students noticed that tire. They started to examine it, and found that it had been in the Bay long enough that animals had started to use it as part of their habitat. It had a few barnacles and some algae attached along the outside, but the real treasures were found in the darkness of the inner rim. For me, the two most exciting finds were a small purple sea urchin, and a couple of chitons that had attached themselves onto the tire.

Students helped us to remove any animals that we could from off the tire and to return them to their natural habitat. It is amazing how even the smallest animals that depend on the Bay can adapt and adjust their lives to the stress that humans force them to face on a daily basis. Talk about habitat diversity!


For more info:
Click here for more info about bottom trawling.
Click here for info about Save The Bay education tours aboard Aletta Morris.










3 comments:

DJ Johnson said...

Abbey,

Does the Otter Trawl drag along the bottom?

Abby Wood said...

Hi David,
Yes, otter trawls are a type of bottom collecting gear. The bottom of the net is lined with a chain that "sweeps" the bottom to collect the animals. Trawls can show what the benthic habitat assemblage consists of better than other gear types. At the end, all animals are returned to The Bay where they came from, and the students (and summer campers) have a memorable connection to The Bay.

Unknown said...

Welcome to RI's blogosphere Abby!

Tom
RIReport.com