Whether fishing for Pacific or Atlantic salmon, you will need to use a rod that will be capable of handling the species you are after. With so many salmon fishing rods available, you will need to either do your own research or talk to an expert who can advise you on your options.
The type of fishing you do is going to determine what kind of rod you will use. If you use a spin casting reel, not just any rod will do. It is going to depend on a few things like how wide the river is and what is the potential size of the salmon you are hoping to catch. You won't be able to cast your lure where the fish are if the rod isn't the right length or stiffness.
If you're fishing for salmon from a boat, then a shorter, stiffer rod will be required. You may prefer a single handed rod over a 2 handed rod or maybe you like a one piece rod versus a 3 or 4 piece rod. You can even match your rod to the type of lure that your using.
For fly fishing, it gets even more complicated. If you are a purest, you'll want a cane or greenheart rod and these vary in length and weight as well. If you're like most anglers, you'll prefer a more modern fly rod that is made from graphite so it is lighter and has more backbone than the old ones. Fly rods can be single handed or double handed and of course handle they all handle different weight lines.
If you are into spey fishing, then a spey rod will be your pick. You can have a single spey that is typically about 11 feet long and handles a 7 to 8 weight line or a double handed spey rod which is much longer. They come in lengths of 11 feet to 15 feet or more and are capable of handling 9 to 12 weight fly lines. Some are 3 piece and some are 4 piece and all are available with different actions.
So you see that with salmon fishing rods, there is a lot to think about before buying one. Talk to other anglers and salmon fishing guides to see what their experience has taught them. Most likely, you will end up with several different salmon fishing rods so you can maximize your opportunities whenever you go fishing!