Haven't got to the point where I can feed the Walrus yet, I'm still chasing Murlods for stuff. But if experience of previous items such as the Carnival Platform is anything to go by, if your warehouse is full you lose the reward, which makes it all fairly pointless.
I've made some progress in the quests related to feeding the walrus...
But, be warned:-
If you are anywhere close to this quest:
There are three types of so called "dives" (or deals) when the walrus is fed. Each dive (deal) costs an increasing number of fish (the fish need to be earned first).
Upon feeding the fish to the walrus:
1. You complete the first deal (the other two are blocked at this stage). The first deal costs 20 fish.
2. After completeing the first deal, a timer starts to work (it times for 24 hours), during this time only you can order the second and the third deals. The 2nd deal costs 30 fish and the 3rd deal costs 60 fish.
3. If you do not complete deals 2 and 3 in time, the quest will start from the beginning (only first deal available, the other two blocked).
I think that you can buy more time to complete deals 2 and 3 by using crystals, but I'm not totally sue of this and it's unlikely to be worth doing this.
I assume that you get a reward for doing just the first deal, even if you can't complete the 2nd and 3rd deals in time. Similarly if you complete 1 and 2 but not 3.
Now, as the fish take a minimum of 5 hours to earn 3 fish, you can see that it will take some effort and time to get sufficient fish to make even the first deal with the walrus which costs 20 fish. To hope to make walrus deals 2 and 3 then you really need a minimum of 120 fish before launching into the 24 hour window for walrus deals 1, 2 and 3.
I haven't yet done any walrus deals so I don't know whether the resultant prizes at each of the 3 walrus-deal levels are decent.
I imagine that the prizes will not be worth all the effort, but it will be necessary to do 10 walrus deals to complete the main quest.
(It all becomes a little more clear when you get the walrus which may be some way off for lower level players).
Hope this makes sense to a few of you. (Can you tell that I'm bored with Airport City).
I need to get a life!
Nutty