You can't catch junk from pools, which are like fishing "nodes". The little schools of fish you see floating around count as pools and I believe wreckage does too. Fishing in regular water will still give you junk if your skill's too low.

Also, I have one thing to say to whoever wants this title/achievement:

Mr. Pinchy.

That's all.

I got my Mr Pinchy after a few tries. One loop of Terokkar Forest's highlakes yielded nothing, so I logged for a few hours and tried again. Fished him up in the Hordes lake, and got the pet on the first attempt. Was ecstatic.
Won the Kalu'ak Tournament last Saturday, so I have just the coins, the rare catch and 1 more Outland Fishing Daily to get for Salty.

Mr. Pinchy really isn't so bad. I've caught him three times. The first time I actually lost him due to the BoP dialog box and me being too quick on the recast. In my experience, it shouldn't take much longer than an hour or so to get him if you've got an epic flier to buzz around the upper lakes with.

Mr. Pinchy took me over 1400 casts.

By the time I hit 'Salty', I was well over 14,000.

Gotta love the bobber game though. To summarize: "Wait for it... Wait for it..." *Splash* CLICK DAMN YOU! CLICK!!!!

Yeah, it's uber relaxing. :D