The following has happened in winter 2006.

I claim to have completed this task by building a giant magnet on a rope [evidence #1, #2]. Every single disk of rare earth magnet has a theoretical holding capacity of 100kg on a flat surface. This gives a theoretical recovery capacity of 700kg - and significantly less on round surfaces and with metal particles gathering on its surface.
The rope is a waterproof 50m speleologic (static climbing) rope.

Using this rope, I have gone fishing on the Torfstraßensteg in Berlin, Germany. [cf. territory] This is an pedestrian bridge spreading over an inner city channel in proximity to the Westhafen port. I was able to pursue my activity unbothered by the bypassers, and the occasional police vessel patrolling the waters. I have, of course, removed the rope from the water as soon as a vessel was within sight.

This location should prove to be the most successful location out of three attempts at fishing for scrap metal. I had originally hoped for bicycles or traffic signs, but I guess I would have to choose a more touristic area for traces of that kind of vandalism. What I detected were pieces of steel cable, an eye bolt, and a cheap, and severed bike lock. [evidence #3, #4]

I was able to pursue the origins of the bike lock to the company Burg & Wächter, from the inscription. In an email to the company, I was told that the type of lock was produced until 1991.

The name of the cat is Audrey.