The arrival of tropical marine species, including venomous yellow-bellied sea snakes and increased stingray populations, poses potential risks to beachgoers and fishermen along the California coast. Juvenile white sharks, while not necessarily increasing danger, may require adjustments in human behavior to ensure safety. Stingray injuries are expected to rise significantly, with lifeguards already treating thousands annually. Globally, El Niño's impacts on marine ecosystems could disrupt fisheries, affect food availability for sea birds and mammals, and alter rainfall patterns, potentially impacting agriculture and water resources in affected regions.