​The purpose of the Sonar project is to bring new technology to salmon research in the Miramichi River. We are using sonar (SOund NAvigation and Ranging) for counting Atlantic salmon. ​Sonar allows fast and accurate fish stock estimates. ​ When the information of returning adult salmon is available faster, it is possible to make in-season fisheries management decisions based on collected data.​

Research: Improving the sonar fish counts

Although the technology has already proven to be useful, there is still a lot to do before the sonar counts can be fully utilised in the Miramichi River. A research team from Canadian Rivers Institute at University of New Brunswick is testing and working to improve the method. 

The three following components describe the most critical tasks for the next years:

1. Accuracy and Precision

One aspect of the research project is to improve the accuracy of the fish counts and make sure that all the fish are registered in our data. The steps we are taking include:

• Improving our study site.
• Comparing sonar counts and length measurements to data from known fish.
• Cultivating this innovative technology to understand how it may unlock further information about fish migration, e.g. relationship of migration and environmental conditions.

2. Fish Species

Currently, the sonar method does not differentiate between fish species. Fish length can be measured from the sonar image, but there are several fish species that are of similar size to salmon, and particularly the one sea-winter salmon, commonly known as "grilse". Our goal is to find a method that can be used to distinguish between the species. We are using migration timing, fish behavior, and their swimming characteristics for species identification.

3. Automated processing

Fish counting will never be fully automated: River research is always challenging and one can never be ready for all the surprises nature has in store for us. 

​However, one advantage of using sonar to count fish is the smaller need of staff. While other fish counting methods can be very laborious, sonar data can be processed with computers. We are working to make things faster by automating large parts of the process. 

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