Was the camera sideways when you took this shot? Since the streaks go up and down, I'm having trouble understanding how the shutter could cause such a problem if the slit ran from top to bottom. If the shutter slit ran side to side (oriented against the photo you posted), then I could see a sticky shutter with an inconsistent speed causing a weird issue like this. If the shutter ran from top to bottom, then the only thing I could think of would be a dirty shutter slit, partially blocking the film. Like maybe some stray strings or other junk partially blocking the light path. If they were light streaks, instead of dark streaks, I might be inclined to think you have some pinholes in the shutter curtain overexposing certain areas.
Otherwise, I'm inclined to think this is a development issue. If you use too small of a pan and don't vary your agitation method enough, you can get standing waves which might look similar to that.