How many fish live here!?!

Thursday, January 17, 2013 by Meredyth Eufemia

Scientists and fishermen are both very interested in how many fish there are in the Gulf of Maine. This fall, a group of 10 lobstermen and four scientists from GMRI set out to find just how many herring  are in the nearshore area of the Gulf of Maine. Scientists want to answer this question so they can help set fishing regulations and lobstermen are interested because they often use herring to bait their lobster traps.

 Scientists provided the lobstermen with sonar equipment, often referred to as fish finders. The transducer is the part of the system that goes under the water and is attached to the bottom of the boat. The transducer is about the size of a small dog!

 The lobsterman would then go out over night once a week while the sonar system used sound waves to create images like this one of what is under the boat. Sonar systems work similar to how bats use sound to “see”.

The thick brown line shows us where the ocean floor is. The patches above that show us schools of fish. Scientists can then use these images to estimate how many fish are in the area of the study. 

The ten fishermen that took part in this study are from different areas along the coast of Maine. When you put all their data together it stretches the entire coastline! The area covered by this study means that scientists have a more complete estimate of how many herring come into coastal Maine waters to reproduce.

The blue lines show the trips that the boats made while collecting data.

In total the boats completed 69 surveys over the course of the fall. Added together that’s 4140 miles traveled. If stretched across the Atlantic it would reach Europe!

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