Herrings Mystery Cache

The cache is not at the posted coords - it swam upstream.  But if you use the right bait, you may catch this one. ><((((((0>

To find this cache, you must visit aquariums and fisheries around the world  (not really, but play along).   Your route will take you from

Berlin to Königsberg

Königsberg to Riga

Berlin to Rome

East Ukraine to South Ukraine

Königsberg to East Ukraine

Berlin to Belgrade (but omit the trip between Salonika and Rhodes)

East Ukraine to Königsberg

Berlin to Oslo (but omit the trip between Rome and Berlin)

Berlin to La Roche  (but omit the trip between Central Belarusse and Königsberg)

Berlin to Rome

Copenhagen to Berlin

Königsberg to North Ukraine (but omit the trip between Belgrade and Berlin)

Salonika to Berlin

Rome to Tunis

Rhodes to Salonika

You can validate your puzzle solution with certitude.