What and how much you catch depends to an extent on what you use for bait, but Washington fish seem to regard the rules of angling as made to be broken. We've caught cats, supposed to use their "whiskers" to forage exclusively by smell, on brand-new rubber worms, and almost everything down there seems sometimes willing to take bloodworms or a nightcrawlers. Shrimp or table scraps can at times produce surprising catches.
If you're Metrofishing, however, you must make yourself as portable as possible, not to mention socially acceptable to your fellow passengers, so plan a little in advance. A foam cup of worms will slip easily into a knapsack or cooler. Messy but effective chicken livers require a leakproof container with a tight lid. Artificial lures are no problem, and you can always stick a few rubber worms in your pockets in case the live baits don't produce.
Try using 12-pound line, since you'll often be casting from seawalls a dozen or more feet above the water, and hoisting your protesting catch quite a distance. While a net with a long-sectioned pole can work in these spots, a strong line is cheaper and less bulky.
A knapsack or small shoulder bag will accommodate the few other things a Metrofisher needs: a pack of hooks (45 to 75 cents for six, depending on the store and hook size), a bunch of sinkers of different weights, some bobbers if you use them, a knife to cut your line or scale your catch, a rag to clean things up and a couple of all- important plastic bags.
Plastic bags are the sine qua non of Metrofishing. You can fit all your gear into a large heavy-duty trashbag; a second should be set aside for your catch, which your fellow passengers would just as soon not look at or smell. Bring a bag, too, for the trash you're sure to find; the Park Service has discreet litter baskets all over, so you won't have to lug it very far.
Since you have to walk a little to reach the fishing spots, you don't want to tote a lot of bulky gear. Army surplus field pants have all kinds of handy pockets, and a lot of the elaborate paraphernalia the military designed to hang on a web belt can be adapted with a little imagination. For instance, a leakproof belt pouch designed to contain chemical warfare agents costs a couple of dollars and is great for holding messy chicken livers and even earthworms if not closed too tightly.
The only other thing you need is a Farecard.