Or you can sit at cape westwind futilely trying to catch the titanic sawfish , 'bah another silver shark' you will say dozens of times.
the silver shark is a level 41 fish, you have to catch a HQ version of a small fish (goby/fm sardine), then use that fish as bait and hope a silver shark bites, they can be caught at lower levels but some will escape you. they are a pain to catch don't expect to catch hundreds an hour or anything, maybe 20 or so, but its all down to the RNG.
This, by far, is the best place I've found. Rat Tails are perfect for this, sometimes you catch the shark first shot instead of having to mooch.