The Galapagos sea lion faces various threats. In the 19th century, sea-lions worldwide were hunted for their meat, skin and oil. The hunting of some sea-lions, including the Galapagos species, has now been banned and populations have recovered (2). Galapagos sea lions are still vulnerable to human activity as their inquisitive and social nature means they are more likely to approach areas inhabited by humans. This brings them into contact with fishing nets, hooks and human waste, all of which can be fatal (6). There are also problems resulting from the increase in numbers of deep-water tuna and billfish fisheries as these sea-lions become victims of bycatch (7). Research indicates that the majority of these incidents (67 percent) involve juveniles, probably due to their more curious and playful nature (7). These marine mammals are also negatively affected by the phenomenon El Niño. During El Niño 1997 and 1998, Galapagos sea lion populations of the main colonies declined by 48 percent. Many sea lions migrated and, amongst those that stayed in the Galapagos Archipelago, there was high mortality due to starvation (7). A viral disease, known as sea lion pox, is another threat to this marine mammal (5). The illness is spread by mosquitoes and causes paralysis, which in turn prevents the sea lion from feeding and may result in death.