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Well, He was speaking to fishermen. :) But what do you mean?
True, he was speaking to fishers vice hunters. But I think that very little, if anything, in God's plan is by accident. Consider the differences between fishing and hunting (I exclude spearfishing, as that is essentially hunting for fish).
The net fisher selects an appropriate spot and casts his nets out. The fish that are caught in the net are brought back in. If there are no fish to catch, then the net fisher will cast his nets out again.
The hook fisher must provide some sort of bait to attract the fish to the hook. The fish must bite the hook first, before being drawn back into the boat (or the shore or whatever).
The hunter, on the other hand, selects his specific target, stalks the target, and then attacks the target with an arrow, a spear, or a bullet.
For the fisher to be successful, the fish must take a little bit of action (swim into the net, bite the hook, etc.). The fisher cannot, on his own power, force the fish to be caught.
For the hunter to be successful, the hunter must be smarter than the hunted. He must take the action to attack the target. No cooperation on the part of the hunted is required (other than being inept enough not to detect the presence of the hunter and run away).
Both the fisher and the hunter may use some techniques to attract their targets. They might use bait, decoys, scent, or something else. But the presence of those techniques will not alter the fact that the fish must either swim into the net or bite the hook, while the prey only need stand still long enough (or move slow enough) to be killed.
Are you seeing an analogy in the gospels yet?