Some seals die because sharks are killing them. Some male seals kill the young seals and some are just curious and get tangled in fishermen's nets. They die of starvation or strangulation. Hawaiian Monk Seals have been endangered since 1976. Fishing is also a threat to Hawaiian Monk Seals.
Sharks are one of the biggest threats.
Some seals have been found with parts of their bodies bitten off. Some seals have even been found inside of sharks.