Leeward chain was first discovered by the prehistoric Polynesians and the islands remained uninhabited until discovered by Europeans in the 19 th century. Volcanoes can be found on some of the islands. There are about 1500 Hawaiian monk seals left in the world. These seals suffer mainly from humans disturbing them and aggressive males that attack the female and the pups during the mating season. Pups die constantly from disturbance during their suckling times due to attacks from aggressive male monk seals.
Sharks are a problem for the Hawaiian monk seal, as are commercial fishing nets.
Many sick and dying seals were observed in the first half of 1978. Samples of their livers were taken from some of the seals. The samples indicated that there was a poison called ciguatoxin, a toxin produced by protozoan that is concentrated through the food chain making the flesh of the affected fish highly toxic to mammals. Ciguatoxin outbreaks occur when a coral reef has been disturbed. Pollution poses threat to seals because it concentrates in body fat which seals have a lot of.