Regional airlines offer it to entice firstclass passengers. Most eager consumers of sharkfin soup probably aren't aware that there's a major problem with the rapid and uncontrolled growth in its popularity. Simply stated, sharks can't keep up. They have been around for some 400 million years and are arguably among the most successful organisms on the planet. Found globally, sharks have adapted to a multitude of environments.
Sharks are slow to reproduce.
Certain species take over 20 years to reach breeding age. This means that the common fishing practice of taking nearly all the adult sharks from a reef practically extinguishes the shark population for the foreseeable future, perhaps for good. To make matters worse, most shark species produce few offspring when they do mate. This contrasts with other fish, which reach maturity rapidly and produce thousands of offspring in a single mating. As a consequence, shark populations have a very difficult time replenishing themselves through natural patterns of reproduction.