Have heard of a old retired guy with a real passion for salmon fishing and he spent most of his free time targeting them on the river. Was told the story a few years back and the details have become blurred but I beleived he caught around 5 salmon a year from the Wairau. Have no idea how that compares with the rivers further south. Last summer heard of a trout angler who spent a lot of time on the river, he caught several hundred trout but also a couple of Salmon.
The other Salmon option is to fish the Clarence which is about a hour to the south. Have spent very little time at that river but have seen a couple of Salmon caught, one from the surf and another far upstream. Most days during the summer there is a few keen salmon anglers at the mouth chasing them so they must be there, or try for them off the beach at Kaikoura during the spring.
Whitebait, like anything to do with fishing their numbers are right down but it is normally possible to catch a feed. Large runs do occur a few days a year where it is possible to catch many kg’s of them.