Conclusions
I believe that I was successful in determining whether or not a fish finder can detect objects, however I am still unsure of the best way to deploy a fixed sonar to track the migration patterns of fishes. I had limited success with the side scan portion of the transducer, but was able to get good pictures from the lower frequency conical sections. Using the recordings to determining the species based on its target strength, or logarithmic measure of the proportion of the energy backscattered by the object, will be a difficult task. Using the recordings to determine the size will also present quite a challenge.
The instrument I used only recorded information on an SD card. I am currently looking for and have found a sonar that has video output. With video output I can gather nearly an unlimited amount of recorded information with a DVR device. Once I have the new sonar I can design a frame to deploy the instrument at the bottom of the railroad bridge, or another accessible underwater fixed location. After that I need a reliable power source and a secure place to store the equipment necessary to gather data.
To evaluate the data I need to begin calibrating the sonar to figure out how far away an object is based on the target strength. Different species of fish will hopefully have different target strengths as well. The next step will be evaluating and processing the frames in a program like Matlab to hopefully provide me with useful information. Problems that may arise are whether or not the fish are schooling as they swim past the sonar. If they are piled on top of each other I don't believe I will be able to separate the two fish from each other very easily. To ensure I am detecting fish correctly I will need to have a redundant system in place. This may include a camera when the water clarity is decent or figure out a way to capture the fish after they pass the sonar to determine size and species.
Any way I look at it I can expect to spend many hours in a lab or in the field gathering copious amounts of hopefully useful information to evaluate.
The instrument I used only recorded information on an SD card. I am currently looking for and have found a sonar that has video output. With video output I can gather nearly an unlimited amount of recorded information with a DVR device. Once I have the new sonar I can design a frame to deploy the instrument at the bottom of the railroad bridge, or another accessible underwater fixed location. After that I need a reliable power source and a secure place to store the equipment necessary to gather data.
To evaluate the data I need to begin calibrating the sonar to figure out how far away an object is based on the target strength. Different species of fish will hopefully have different target strengths as well. The next step will be evaluating and processing the frames in a program like Matlab to hopefully provide me with useful information. Problems that may arise are whether or not the fish are schooling as they swim past the sonar. If they are piled on top of each other I don't believe I will be able to separate the two fish from each other very easily. To ensure I am detecting fish correctly I will need to have a redundant system in place. This may include a camera when the water clarity is decent or figure out a way to capture the fish after they pass the sonar to determine size and species.
Any way I look at it I can expect to spend many hours in a lab or in the field gathering copious amounts of hopefully useful information to evaluate.
Special Thanks to:
Rick for letting me borrow the Humminbird SI sonar. Invaluable Wisconsin DNR advisors and friends, Dick Lathrop and Kurt Welke. Hoi Lai for questioning everything I do. Bob for letting me use his ice fishing equipment and helping me look silly on Monona Bay. My professor Chin Wu for introducing me to this idea, and you for spending the time to read this website.
References
Humminbird Website http://www.humminbird.com/
Fisheries acoustics: theory and practice E. John Simmonds, D. N. MacLennan
HTI:http://www.htisonar.com/what_are_hydroacoustics.htm
Wisconsin State Journal: Without the Carp, Lake Wingra Cleans Up, September 1st 2009.
http://host.madison.com/wsj/news/local/environment/article_c268c081-641a-505e-bcf9-f4ea7ef6d869.html
Fisheries acoustics: theory and practice E. John Simmonds, D. N. MacLennan
HTI:http://www.htisonar.com/what_are_hydroacoustics.htm
Wisconsin State Journal: Without the Carp, Lake Wingra Cleans Up, September 1st 2009.
http://host.madison.com/wsj/news/local/environment/article_c268c081-641a-505e-bcf9-f4ea7ef6d869.html