An electronic fishing device for facilitating trolling a fish-catching element in water and a related system, method, and use, the fishing device including: a first sensing element for obtaining a first indication relating to water temperature, a second sensing element for obtaining a second indication relating to the depth of the device, a steering member for adjusting the depth of the device, a processing unit for controlling, via the first and/or second indication provided by the first and second sensing elements, the steering member so as to guide the device relative to at least one element selected from the group consisting of: the position of the thermocline layer, a predetermined depth, and a predetermined temperature. In addition to fishing the disclosed device may be utilized in marine or other underwater research.
