Harborside shops and some meat/fish shops in larger towns provide freezing, smoking and shipping service for people who want to send their salmon or halibut home.
Overnight delivery can be had through FedEx and other services. Travelers can also take a cooler home on the jet if they're confident of getting there before the fish, packed in ice or gel packs, thaws.
Ice is readily available in bags of between 5 and 10 pounds at grocery and convenience stores and at gas stations.