I had made a circuit similar to this, not for fishing though, what I had used was an old stepper motor connected to a schmitt buffer connected to a monostable 555 timing circuit. When the stepper stepped, it generated a pulse, which was buffered by the schmitt and triggered the timing circuit which lit up an LED.
It could've been modified to go through a counter first, then after x number of pulses it would trigger the timer.
You could also use a comparator instead of schmitt buffer to give better control over the triggering threshold.
as for the RF part, instead of a LED, you could send a pulse over one of those cheap RF transmitter/receiver pairs (like from Robotshop.ca, or Sparkfun.com)