Where did all the abalone go?

There was a time when the rocky reefs of Monterey Bay shimmered with abalone shells — red, green, even the ghostly white. You didn’t need to be a diver to spot them; they clung to intertidal rocks and played a crucial role in the underwater rhythm of the coast. Today, that rhythm feels broken.

So where did they go?

Their disappearance wasn’t caused by one single event, but a series of ecological dominoes:

  • Marine heatwaves, like the infamous Blob in 2013, warmed coastal waters beyond the comfort zone for giant kelp — abalone’s primary food source.

  • Sunflower sea stars, key predators of purple sea urchins, were wiped out by a mysterious wasting disease.

  • Urchin populations exploded, consuming entire forests of kelp and leaving barren reefs in their wake.

  • Abalone, unable to migrate or compete, starved. Their numbers plunged not just from hunger, but also from stress, disease, and the lingering impact of overharvesting in past decades.

The result? A once vibrant kelp ecosystem reduced to rubble and urchins. Monterey’s coastline became a cautionary tale of what happens when ecological checks and balances fall apart. The sea otter numbers were already fragile, and their absence in certain areas amplified the damage.

Why do abalone matter?

Abalone aren’t just pretty shells. They’re keystone grazers, quietly managing algae, clearing rocky surfaces, and making space for kelp to grow. Without them:

  • Algae can overgrow, smothering young kelp and other foundational species.

  • Urchins dominate the grazing niche, but unlike abalone, they don’t know when to stop, turning lush forests into "urchin barrens."

  • Ecosystem diversity suffers, impacting species from rockfish to sea otters — and even the oxygen-cycling capacity of kelp forests.

In short, without abalone, the balance tips — and the entire food web feels the loss.

Up north in Bodega Bay, scientists at the UC Davis Marine Lab are rewriting that story. By raising abalone in controlled environments, caring for them like marine royalty, and reintroducing them to carefully chosen reefs, they’re proving that recovery is possible.

I was wondering if its success offers lessons for the projects I’m working on in Monterey. The first two below, G2KR is doing, but perhaps there is room to collate data together to influence the California Department of Fish and Wildlife policy. The Sunflower Star Lab could learn breeding best-known-methods and possibly how to breed resilient sunflower sea stars. The lab is currently in the initial stages of learning how to breed.

  1. Restore kelp before abalone can return.

  2. Control urchin populations through culling, ranching, or predator support.

  3. Breed resilient abalone strains adapted to today’s warmer, more variable oceans.

Withering syndrome is a bacterial disease that disrupts abalone’s digestive system, causing their muscles to shrink and eventually detach from rocks even when food is available. First identified in the 1980s, it’s caused by Candidatus Xenohaliotis californiensis and has spread along the California coast and beyond. Warmer ocean temperatures accelerate its impact, especially during marine heatwaves like The Blob. There’s no cure, only prevention, close monitoring, and breeding for resistance.

It would be fascinating to know where Bodega Marine Lab breeding program stands today. Are new generations of abalone ready to be released? Could their successes ripple southward toward Monterey?

Perhaps it’s time for a field trip.

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