Sunflower stars and the hunger of recovery

The water off English Bay carries a different weight now than it did ten years ago. Below the surface, where kelp forests once swayed above a seafloor patrolled by the largest sea stars in the world, something fundamental shifted and is only now beginning to shift back. The rocky bottom here tells a story of absence and slow return.

The sunflower star (Pycnopodia helianthoides) was the apex predator of these subtidal zones until 2013. Picture an animal the size of a manhole cover, twenty-four arms radiating from a central disc, moving across the rocks with surprising speed on thousands of tube feet. These stars could hunt down sea urchins, abalone, and other mollusks with relentless efficiency. A single sunflower star might consume a dozen sea urchins in a day, keeping their populations in check and preserving the kelp forests that depend on that balance. Then sea star wasting disease swept through the Pacific coast. The sunflower stars began dissolving, their tissue breaking down until nothing remained but empty shells scattered on the sand.

The absence created a cascade. Without sunflower stars hunting them, purple sea urchin populations exploded. The urchins grazed kelp forests down to bare rock, creating what marine biologists call urchin barrens. Species like the northern abalone (Haliotis kamtschatkana), already struggling from overharvest, lost critical habitat as the kelp disappeared. The abalone, large marine snails that graze algae from rock surfaces, need the complex three-dimensional structure that healthy kelp forests provide. They shelter in crevices during the day and emerge at night to feed on drift algae that settles from the canopy above. Without kelp, the seafloor became a simplified landscape of rock and urchin spines.

Now, nearly a decade later, individual sunflower stars are returning to these waters. They appear first as juveniles, small and cautious, but carrying the same predatory potential that once shaped this ecosystem. Each returning star represents a test of whether the marine environment can support their recovery. The survivors seem to carry some resistance to the wasting disease, though scientists are still learning what makes some populations more resilient than others. Where sunflower stars reestablish, urchin populations begin to decline. Kelp begins to recruit in patches. The seafloor starts to rebuild its complexity, one predator-prey interaction at a time. The process moves slowly, measured in years rather than seasons, as each returning star must find enough food to grow and eventually reproduce.

Somewhere below the surface of English Bay, a sunflower star the size of a dinner plate moves through the underwater landscape. Its tube feet test the texture of each rock, chemical sensors detecting the scent trails of potential prey. The water above reflects the late spring light, filtering down to illuminate this careful work of reconstruction. The star's presence changes everything around it, not through force, but through the simple fact of being where it belongs, hunting where it evolved to hunt, maintaining balances that took millennia to establish and only a few years to lose.