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When the sun sets over the open ocean, an extraordinary migration begins. From thousands of feet below the surface, delicate larval fishes, strange gelatinous drifters, tiny sharks, and other remarkable creatures rise into the darkness. For blackwater divers—those who venture offshore at night over deep water—this hidden world comes briefly into view, illuminated only by dive lights and curiosity. 

Marine biologist and underwater photographer Jeff Milisen’s Field Guide to Blackwater opens a window into this otherworldly ecosystem. Drawing on years of firsthand observations and hundreds of dives off the coast of Hawaii, Jeff combines personal stories, scientific insight, and detailed species accounts to introduce readers to the remarkable animals that inhabit the epipelagic ocean at night. The guide highlights the organisms most often encountered by divers and photographers—many of them larval forms that look nothing like their adult counterparts—and explores what these encounters reveal about ocean ecology, behavior, and discovery.

Updated with new data and observations as well as adding 34 more creatures, this second edition can be pre-ordered now through major booksellers and dive retailers, with copies shipping from May 1st. Check out DPG’s review of the first edition here.
 

PRESS RELEASE

Field Guide to Blackwater (2nd Edition) Reveals the Extraordinary Creatures Rising from the Deep Each Night

KONA, HAWAII — [March 23, 2026] — One of the ocean’s most mysterious ecosystems comes to life in Field Guide to Blackwater (2nd Edition), the definitive guide to the remarkable animals encountered during blackwater dives. The highly anticipated new edition is now available for pre-order, with the official release scheduled for May 1.

When darkness falls over the open ocean, a massive vertical migration begins. Larval fishes, gelatinous drifters, tiny predators, and other pelagic organisms rise from depths thousands of feet below the surface. For blackwater divers—those who venture offshore at night over deep water—these fleeting encounters illuminate one of the least understood environments on Earth.

Drawing on hundreds of dives and years of firsthand observation off the coast of Hawaii, Field Guide to Blackwater introduces readers to the fascinating species that appear in divers ’ lights after sunset. The new edition expands the original work with 34 additional animals, updated observations, and new data on seasonal occurrence patterns gathered over years of dives.
 

More than a field guide, the book serves as a gateway into the science and exploration of the open ocean. Through detailed descriptions, real-world observations, and striking imagery, readers gain the tools to identify species and understand the ecological forces behind the ocean’s nightly migration.

Blackwater diving has grown rapidly around the world in recent years, with dive operations now offering expeditions in locations from Hawaii and Florida to the Philippines, Japan, and Indonesia. As the community expands, Field Guide to Blackwater has become the cornerstone reference for identifying the extraordinary life encountered in these dives.

“This book is meant to bring the hidden biodiversity of the open ocean into the light,” the author explains. “Many of these animals are rarely seen alive, and every dive still has the potential to reveal something completely new.”

Field Guide to Blackwater (2nd Edition) is available now for pre-order, with books shipping and available worldwide beginning May 1st.

Book Details

Title: Field Guide to Blackwater (2nd Edition)
Author: Jeff Milisen
Release Date: May 1, 2026
Availability: Pre-order now through major booksellers and dive retailers
Category: Marine Biology / Ocean Exploration / Diving

About the Author

Jeff Milisen is a marine biologist, diver, and ocean explorer based in Kona, Hawaii. Through years of blackwater diving and pelagic research, he has documented hundreds of species rarely observed alive and has helped expand scientific understanding of larval and pelagic marine life.