August 10, 2009
Flexibility is an important factor in planning and conducting field research. There are many factors that influence a successful day; weather conditions including tide information, illness, people, transportation, coordination of resources, other agencies and wildlife. The logistics get a bit tricky to manage. You need to plan for plans to change, that's field work.
Today, we drove 2.5 hours to Bradley, which is north of Bangor, Maine. We worked with Chip Wick, who works for the Maine Department of Inland Fisheries and Wildlife. He is responsible for the electro-shocking boat. Colleen Fuller, Dr. Karen Wilson, Chip and I traveled to the site to launch the boat. There were two women citizen scientists who live nearby who came out to watch the action. It is important to keep local people informed about the research conducted in their own backyard. They can create a positive bridge between the community and the public agencies/colleges trying to gather data.
The site is Blackman Stream, which is the outlet of Chemo Pond that flows into the Penobscot River. The Penobscot River eventually flows into the Gulf of Maine and the Atlantic Ocean.
The boat is equipped with a generator, which creates an electric current in the water to temporarily shock and paralyze the fish within a set radius around the boat. Then, one person sits on the high chair and scoops out the shocked fish with a long-handled net. They then place the fish into a large, water-filled cooler on board. The second person uses a shorter net to collect any escaping fish off to one side. I was able to capture a large pumpkinseed sunfish. That was my contribution for the day. I was trying to be careful not to get electro-shocked myself. We wore rubber waders, a life vest (PFD) and heavy rubber gloves on board as a safety measure.
The purpose for collecting fish is to study the food chain in the Blackman Stream environment. Each fish is identified, measured for length and weight and a muscle tissue sample is collected in the field. To collect the tissue sample, the scales are removed from a tiny area on the fish then a biopsy tool is used to punch a small hole in the muscle tissue of the fish. The tissue of the fish is collected in a small container for processing in the lab and sent out for testing. The fish is then released back into the stream. Some of the smaller fish are removed from the stream. The fish are tested for the ratio of different stable isotopes of Carbon and Nitrogen in their tissues. You are what you eat. Each member of the food chain, predators (top carnivores), omnivores and herbivores have a different ratio of these isotopes in their body. The ratio of the isotopes is one way to determine the relationship among fish in the food chain.
*Video: Dr. Wilson explains her food chain research (choice of 3 formats):
The highlight of the day was capturing a very large chain pickerel. He certainly did not fit well inside the cooler and was difficult to manage because he was so slippery and cumbersome. He did not fit on the fish measuring board because he was too long. He appears to be a top predator and the isotope test results should confirm this statement. Hopefully.... The other fish we caught were American eels, pumpkinseed sunfish, red breasted sunfish, brown bullhead, smallmouth bass, golden shiner, white sucker and several minnows.
*Video: Colleen measuring the large chain pickerel (choice of 3 formats):