Threatened species of Zalophus

Sea lions are killed by entanglement in fishing nets and gear throughout their range, although this problem is now declining. The major culprits are set and drift gillnet fisheries, but entanglement also occurs in troll, purse seine, net pen, trawl and commercial passenger fishing vessel fisheries.

One species of Sea Lion declined by about 50 % to 80% over the past two years. The number of northern Fur Seal pups declined by half between the 1950's and 1980's in the Pribilof islands - the major breeding ground in the Pacific.

Available records show that the fishery causing the highest mortality is the California set gillnet fishery for halibut and angel shark which kills an average of 815 sea lions each year. Excluding the Mexican shark drift gillnet fishery, for which there is incomplete data, it is estimated that a minimum of over 1,400 California sea lions are killed each year by entanglement.