As you will probably know, I like stamps which use pictures to display their subject. I think this set is a great example of this from the 1970s. What makes these stamps so good is that drawings were used rather than photographs which would have included too much details for the small area of a postage stamp. Also the decision to use drawings might have been because of technology at that time. The result is they are interesting, clear and easy to understand.
New Zealand is surrounded by oceans and has always been connected with the sea. This stamp issue is about how the country is gaining wealth and produce from the resources of the ocean while at the same time protecting these resources for future generations.