stylistic:style_transfer, structural:scholar_edition, structural:summarization, structural:expansion, information:classification
Conservation issues

As of 2021, 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. They are ranked as:

Pinnipeds face various threats. 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. Organic chemicals tend to accumulate in these animals since they are high in the food chain and have large reserves of blubber. Lactating mothers can pass the toxins on to their young. These pollutants can cause gastrointestinal cancers, and decreased fertility and immunity to infectious diseases. Other man-made threats include habitat destruction by oil and gas exploitation, encroachment by boats, and underwater noise.

Species that live in polar habitats are vulnerable to the effects of climate change on oceans, particularly declines in sea ice. In 2010 and 2011, sea ice in the Northwest Atlantic was at or near an all-time low and harp seals as well as ringed seals that bred on thin ice saw increased death rates. In the Antarctic, the decreased duration and extent of the sea ice and nutrient availability could potentially reduce the survival of Weddell seal pups and may have important implications for population growth rates. Antarctic fur seals in South Georgia in the South Atlantic saw major decreases over a 20-year study, during which scientists measured increased sea surface temperature anomalies.

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 resist sea lion use. Inland-living New Zealand sea lions face unique human conflicts such as road mortality and run-ins with human infrastructure. Seals also conflict with fisherman. In 2007, MMPA was amended to permit the lethal removal of sea lions from salmon runs at Bonneville Dam. In the 1980s and 1990s, South African politicians and fishermen demanded that brown 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.