What propaganda techniques does the author use to make the catching

of shelled fish seem a poor activity and conversely) the catching of

unshelled fish a worthy and desirable activity?

The author mentions how expensive it is to catch unshelled fish

Explanation:

In the passage, it was stated that fishermen generally move to usual locations of unshelled fish and they had to rent and pay for different amenities in order to catch the fish, Unlike the shelled fish that are relatively slow, the unshelled fish are not. They are usually active and lively in nature and this makes them difficult and expensive to catch.