Complex sentence: Early principal activities were farming, salt works, shipping, whaling, and sheep husbandry, which was very popular due to the introduction of Merino sheep and the beginnings of water-powered mills that could process the wool.
Split into simpler sentences: Early principal activities were farming, salt works, whaling, shipping, and sheep. Sheep husbandry was very popular due to the introduction of Merino sheep and the beginnings of water-powered mills that could process the wool.