Fishing for parts to make the Fishing Rod is awful. I have fished countless nodes in the solo instance and have only found 5 of one component, which only needs one You should be able to get at least one usable part per node. At the current rate I would need several years to complete this quest BTW It doesn't matter if I wear harvesting gear or not, the RNG is too severe.
Chance to obtain the Oceansfull Fishing Rod from the shoals of fish in Trench of Terrors (both solo and heroic) has been increased.