the basking shark has been hunted for its large liver, which has been sold in japan, and has been burned and used in lamps by fishermen in the u.k, whilst the oil has been used in the manufacture of cosmetics. due to the long amount of time it takes to mature, and the slow reproductive rate, the basking shark is vulnerable to over-fishing, and targeted populations are very slow to recover from targeted fisheries. today the biggest threat comes from the demand for the fins for shark fin soup, and from accidental by-catches in the fishing industries. although it is difficult to tell exactly, there has been a report that the population of basking sharks has decreased by 80% since 1950.