Fighting back against supermarkets

After the widely acclaimed campaign to stop upto half of fisherman's catches being thrown back dead into the sea because of the common fisheries policy, it's interesting to note how tescos is approaching the issue for its customers.

John West tuna, in oil or brine, used to be 4 tins for £4.50 - in a sale, they were £3.50 for four tins.
Checking the shelf price of John West tuna today at tesco, the price has shot up to more than £6!

If more fish are being used for the food chain instead of thrown back into the sea dead, the increase in supply of the product, should, in theory, lead to a price reduction.
Tesco have increased their prices, every profiteering helps!