The ocean’s aphotic zones, those places so far from the surface that light will never puncture them, are inky black sanctuaries for otherworldly creatures of the deep. They are lightless refuges for self-illuminating angler fish and vampire squid, pitch-black oases for phytoplankton—and a metaphor for chef Peter Hemsley’s newest San Francisco venture.

Like those impenetrable underwater kingdoms, SoMa’s Aphotic is a darkened sanctuary devoted to the ocean’s riches. Instead of selecting fish, bivalves, and crustaceans on taste alone - a practice which has led to overfishing and the precarious unbalancing of the undersea ecological web - only those caught or harvested locally and sustainably cross its threshold.

On Aphotic’s first seasonal ten course tasting menu, Hemsley and team get creative. The ocean echoes through not just savory dishes like Bodega Bay rockfish and house garum, and Monterey abalone with swordfish bacon and dashi, but through its desert courses, too: a tiny stroopwafel dipped in fish sauce caramel, for example, or a chocolate cream puff filled with reserve caviar.

The exquisitely prepared meal complements the restaurant’s interior, a painstakingly designed space that feels at once like an underwater ghost forest with accents of sculptural driftwood and a wood plank ceiling hewn like the inside of a boat; and a Viking banquet hall with onyx walls and two live fires burning at the dining room’s edge. It’s welcoming like a Scandinavian lodge at deepest winter, dark and cozy but beating with life.

Although the tasting menu isn’t Aphotic’s only option—they have fifteen seats at the bar where a la carte dishes, most of which differ from those on the tasting, are served—it’s an intriguing lineup I’ve been looking forward to since the restaurant opened in March.

The meal begins with a single bite of Mt. Lassen trout (the fish selected by Hemsley, himself) and its roe (smoked by local caviar specialists Tsar Nicoulai) embedded within and on top of a sphere of rice. In my glass is a flor fatal, a cocktail made with smooth raicilla, vermouth, cardamaro, sherry, and Spanish luxumus liqueur.

Aphotic is the kind of high-end, white tablecloth restaurant where they leave no detail to chance, from the time they take your coat at the door to the time they send you home with a bag of housemade confections. An army of well-trained, handsomely dressed staff anticipate your needs and swoop in with trivets and chopstick rests paired perfectly to each dish.

By the third course, I’m tasting not just the quality of the chefs’ technique but the magnificence of the fish and seafood with which they’re working. Bites of raw spot prawns crowned with tiny nasturtium leaves and slivers of apple and radish encircle a garden of golden osetra caviar. Fish crackers made in house accompany the garland, replacing the typical blini with a toothsome crunch.

My favorite dishes of the meal come in quick succession one after another. The milk bread and Dungeness crab curry hollandaise is served with a pillowy, lightly charred roll to dip into a saucer of creamy citrus-and-Japanese-curry gravy punctuated with chunks of sweet crab meat. The white leg prawn risotto and San Diego uni is drenched in a foam of seafood stock and dolloped with a lump of buttery, briney sea urchin. The Pacific skate, a bottom-feeder often considered a “trash fish”, is thick and meaty, its flavor enhanced by a stalk of wood-fired green garlic and smoked wine-and-herb nage.

With the first dessert dish of the meal, things go a little off the rails, and presumably, that’s how Hemsley and executive pastry chef Deirdre Balao Rieutort-Louis like it. They present a delicate oyster in its shell, a dab of mignonette foam on one side, a crisp sea bean on the other. Except the oyster isn’t an oyster at all. It’s ice cream, oyster ice cream, and although I am not a fan, I appreciate the playful nod to the restaurant’s mission.

But there’s still more to come. First a mochi chiffon made with Buddha’s hand and amazake, followed by a set of mignardises, both of which incorporate ingredients from the ocean that taste far better than they sound.

The ten course throughline celebrating sustainable seafood with transparent origins is a success, but you’ll pay generously for its pleasure: $230 per person, plus an additional $150 for the wine pairing (mains on the bar menu range from $35-45). But that’s part of the point, too. Seafood, especially keystone species like salmon and tuna on which ecosystems depend, should be luxury items not the lowest common denominators on a TGI Fridays menu.

From sea to plate, Aphotic approaches fish, bivalves, and crustaceans like the uniquely valuable creatures they are. While not all of us can afford to buy into Hemsley’s extravagance, his ethical perspective is something about which we can’t afford not to take notice

// Aphotic is open for dinner Tuesday through Saturday from 5:30pm to 10pm; 816 Folsom St. (SoMa), aphoticrestaurant.com