The slug couldn’t move further north until it had the right conditions: warmer currents that have heralded its arrival in past blooms.Ī study published in 2011 examined prevous nudibranch migrations and forecast that similar travels would happen again under certain conditions. They take their coloring from their sole food source, a pink bryozoan that encrusts rocks from Baja California to Canada. Only about one inch long, the slugs make up for their petite size with the sheer vibrancy of their coloring, clashing brilliantly with the dull browns, greens and grays of the intertidal. Unlike its terrestrial relations, it doesn’t mind all the salt. The Hopkins’ Rose is a tiny type of sea slug. Their movements are just part of the many unusual conditions near our shores-and they hint at longer-term trends that may take hold as Earth’s climate settles into new patterns. But in spring and summer 2015, these beautiful pioneers were carried en masse along the coast by warmer waters. Traditionally, the nudibranchs populate the tide pools of southern California. Though the Hopkins’ Rose has immigrated to Monterey Bay and the rest of the central coast, it isn't an invasive species. It edges its way under an encrusted rock while I watch, entranced. From its squishy body to the waving tentacles covering its back, the slug is uniformly pink. She points into the pool near her feet, and I zero in on the slug right away. “We’ve been seeing them all morning.” I hop from rock to rock over to the waving volunteer in a doomed attempt to stay dry.

When she looks more closely, the volunteer sees a small but stunning specimen of Okenia rosacea, more commonly known as the Hopkins’ Rose nudibranch.

From a distance, it looks like a piece of trash-a Day-Glo pink tentacle toy from a 50-cent vending machine. One observer pauses when she sees an eye-catching object clinging to a rock in a tide pool. 11, 2015-A salt-laden breeze buffets a scientist and her volunteers as they clamber on the rocky reef near Half Moon Bay.

California sea of roses