AAAAIIIIEEEEEEEE!!!!!!!! They're Coming - Masses Of Sea Slugs Moving North Along CA Coast
A colorful flood of tiny southern sea slugs rarely seen in the waters off Northern California is puzzling scientists concerned about the warming ocean. The numbers of humpback whales and dolphins, normally more abundant off the Southern California coast, have been increasing in Monterey Bay, and now inch-long sea slugs are suddenly concentrating here in spectacular masses, biologists in San Francisco and Santa Cruz have found.
This isnt El Niño weather, but ocean temperatures along the Northern California coast are higher by several degrees than they have been in decades, and as the warming continues, the immigrant sea slugs are finding it comfortable to thrive farther north. Its a population explosion, said Terry Gosliner, the curator of marine invertebrates at the California Academy of Sciences and a longtime expert on the sea slugs, known to scientists as nudibranchs.
One species of the southern nudibranchs, popularly known to biology students and home aquarium collectors as the Hopkins Rose, is scientifically called Okenia rosacea. Their bright pink bodies are normally common in tide pool areas near Los Angeles and San Diego but uncommon north of San Luis Obispo.
However, they have recently been observed blanketing tide pools as far north as Humboldt County.
EDIT
http://www.sfgate.com/science/article/Sea-slug-masses-migrate-to-Northern-California-6049772.php