Has anybody developed an Airborne Fish Finder, mounted on the belly of an aircraft?

Question

1. Can such Airborne Fish Finder can direct fishing boats on the ground to a specific location?
2. Do different types of fishes actually have some kind of spectral emission or radiation that can be detected using such aerial payload?
3. Can such aerial payload build up an electronic data base on fishes in a particular geography, and then try to compare known signatures everytime it detects a signature?
4. Would such signature be known as a species specific frequency, signature, emission or anything else, I mean technically?
5. If such a payload does exist, can it be effective airborne alone, or does it have to "shakehand" with a water based SONAR to get better accuracy?
6. Can such a payload give information regarding the species, speed of travelling, direction, depth, approximate school size?

Answer 1

TCAS is euphamistically referred to as a "fish finder"

Answer 2

I see why you chose the moniker "Question man".