We want to go fishing to figure out if some heavy metal pollution is present in the food chain (fishes), so we are trying this device to make our data gathering more successful. Some fishes might be attracted by the sound of smaller fishes eating. The challenge is to find this frequency.
Our own fish caller circuit on github.
Documentation of fish caller workshops
- Workshop Japan-Jogjya - Video documentation on Workshops on Lifepatch vimeo
- Lifepatch explained in their own words
- The Koganecho Bazaar Residency in Yokohama, 2014 (Lifepatch site)
- Bamboo Curtains Residency, 2015 (Lifepatch site)
- Design It Yourself Surabaya, 2015 (Lifepatch site)
A fish caller circuit kit 
!985 Electronic Circuit Diagram > Alarm > Beeper Sound  Advertisement for fish caller bait 
A video of the above fish caller kit 
A startup (?) making fish callers ? 
Angler's bite booster circuit: http://chemelec.com/Projects/Misc-Circuits/Fish-Caller.jpg
A patent for a fish caller 
Finally, this one looks doable, with schematics and all components values  555 Astable Circuit Calculator