As of 2019, the International Union for Conservation of Nature (IUCN) recognizes 36 pinniped species.
With the Japanese sea lion and the Caribbean monk seal recently extinct, ten more are considered at risk, as they are ranked "Endangered" (Hawaiian monk seal, Mediterranean monk seal, Galápagos fur seal, Australian sea lion, New Zealand sea lion, Caspian seal, and Galápagos sea lion) or "Vulnerable" (northern fur seal, hooded seal, and walrus).
Species that live in polar habitats are vulnerable to the effects of recent and ongoing climate change, particularly declines in sea ice.
There has been some debate over the cause of the decline of Steller sea lions in Alaska since the 1970s.

Some species have become so numerous that they conflict with local people.
In the United States, pinnipeds are protected under the Marine Mammal Protection Act of 1972 (MMPA).
Since that year, California sea lion populations have risen to 250,000.
These animals began exploiting more man-made environments, like docks, for haul-out sites.
Many docks are not designed to withstand the weight of several resting sea lions.
Wildlife managers have used various methods to control the animals, and some city officials have redesigned docks so they can better withstand use by sea lions.
Sea lions also conflict with fisherman since both depend on the same fish stocks.
In 2007, MMPA was amended to permit the lethal removal of sea lions from salmon runs at Bonneville Dam.
The 2007 law seeks to relieve pressure on the crashing Pacific Northwest salmon populations.
Wildlife officials have unsuccessfully attempted to ward off the sea lions using bombs, rubber bullets and bean bags.
Efforts to chase sea lions away from the area have also proven ineffective.
Critics like the Humane Society object to the killing of the sea lions, claiming that hydroelectric dams pose a greater threat to the salmon.
Similar conflicts have existed in South Africa with brown fur seals.
In the 1980s and 1990s, South African politicians and fisherman demanded that the fur seals be culled, believing that the animals competed with commercial fisheries.
Scientific studies found that culling fur seals would actually have a negative effect on the fishing industry, and the culling option was dropped in 1993.

Pinnipeds are also threatened by humans indirectly.
They are unintentionally caught in fishing nets by commercial fisheries and accidentally swallow fishing hooks.
Gillnetting and Seine netting is a significant cause of mortality in seals and other marine mammals.
Species commonly entangled include California sea lions, Hawaiian monk seals, northern fur seals and brown fur seals.
Pinnipeds are also affected by marine pollution.
High levels of organic chemicals accumulate in these animals since they are near the top of food chains and have large reserves of blubber.
Lactating mothers can pass the toxins on to their young.
These pollutants can cause gastrointestinal cancers, decreased reproductivity and greater vulnerability to infectious diseases.
Other man-made threats include habitat destruction by oil and gas exploitation, encroachment by boats, and underwater noise.
As of 2019, the International Union for Conservation of Nature (IUCN) recognizes 36 pinniped species. With the Japanese sea lion and the Caribbean monk seal recently extinct, ten more are considered at risk, as they are ranked "Endangered" (Hawaiian monk seal, Mediterranean monk seal, Galápagos fur seal, Australian sea lion, New Zealand sea lion, Caspian seal, and Galápagos sea lion) or "Vulnerable" (northern fur seal, hooded seal, and walrus). Species that live in polar habitats are vulnerable to the effects of recent and ongoing climate change, particularly declines in sea ice. There has been some debate over the cause of the decline of Steller sea lions in Alaska since the 1970s.
Some species have become so numerous that they conflict with local people. In the United States, pinnipeds are protected under the Marine Mammal Protection Act of 1972 (MMPA). Since that year, California sea lion populations have risen to 250,000. These animals began exploiting more man-made environments, like docks, for haul-out sites. Many docks are not designed to withstand the weight of several resting sea lions. Wildlife managers have used various methods to control the animals, and some city officials have redesigned docks so they can better withstand use by sea lions. Sea lions also conflict with fisherman since both depend on the same fish stocks. In 2007, MMPA was amended to permit the lethal removal of sea lions from salmon runs at Bonneville Dam. The 2007 law seeks to relieve pressure on the crashing Pacific Northwest salmon populations. Wildlife officials have unsuccessfully attempted to ward off the sea lions using bombs, rubber bullets and bean bags. Efforts to chase sea lions away from the area have also proven ineffective. Critics like the Humane Society object to the killing of the sea lions, claiming that hydroelectric dams pose a greater threat to the salmon. Similar conflicts have existed in South Africa with brown fur seals. In the 1980s and 1990s, South African politicians and fisherman demanded that the fur seals be culled, believing that the animals competed with commercial fisheries. Scientific studies found that culling fur seals would actually have a negative effect on the fishing industry, and the culling option was dropped in 1993.
Pinnipeds are also threatened by humans indirectly. They are unintentionally caught in fishing nets by commercial fisheries and accidentally swallow fishing hooks. Gillnetting and Seine netting is a significant cause of mortality in seals and other marine mammals. Species commonly entangled include California sea lions, Hawaiian monk seals, northern fur seals and brown fur seals. Pinnipeds are also affected by marine pollution. High levels of organic chemicals accumulate in these animals since they are near the top of food chains and have large reserves of blubber. Lactating mothers can pass the toxins on to their young. These pollutants can cause gastrointestinal cancers, decreased reproductivity and greater vulnerability to infectious diseases. Other man-made threats include habitat destruction by oil and gas exploitation, encroachment by boats, and underwater noise.
Pinniped