The Pacific sea nettle is a drifting predator with a golden, venomous armament

Nature · Published 3 October 2026 Swipe more like this →

In short: The Pacific sea nettle, Chrysaora fuscescens, is a striking jellyfish known for its golden-brown bell and long, trailing tentacles. While its sting can be irritating to humans, this cnidarian is a master of passive hunting, drifting through the northeastern Pacific and using complex venom to secure a diverse diet of marine life.

Described by Johann Friedrich von Brandt in 1835, the Pacific sea nettle derives its genus name from the Greek mythological figure Chrysaor, meaning 'he who has a golden armament.' This refers to the creature's distinct golden-brown bell, which can reach over one meter in diameter, though most individuals remain under 50 centimeters. Trailing behind this bell are 24 maroon tentacles and whitish oral arms that can extend up to 15 feet, forming a deadly net for unsuspecting prey.

These jellyfish are carnivorous drifters that rely on nematocysts—specialized cells that launch barbed stingers upon contact. These stingers inject a cocktail of proteins, including pore-forming toxins and proteases, which disrupt tissues and cell membranes. While this venom is effective against zooplankton, crustaceans, and small fish, it is generally nonlethal to humans. Interestingly, the nettle itself is not invincible; it serves as a food source for marine birds, large fish, and leatherback turtles, which seem immune to its defensive sting.

The life cycle of the sea nettle is a complex process involving both sexual and asexual reproduction. Fertilized eggs develop into planula larvae on the female's oral arms before settling as polyps on solid surfaces. These polyps then reproduce asexually through budding, eventually metamorphosing into the free-swimming medusa stage. In recent years, populations have surged off the coast of Oregon. While some experts view this as a potential indicator of climate change, others suggest that human-driven nutrient runoff, which fuels algal blooms and increases food availability, may be the primary driver behind these dense, problematic swarms.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Known as flower animals, these ancient marine predators build the world's most diverse ecosystems.
• True jellyfish are ancient, cup-shaped predators that have thrived since the Cambrian period.
• The sea wasp is a nearly invisible predator that can kill in five minutes.
• These predatory marine animals are named after flowers but hunt with harpoon-like venom cells.
• Nettle cells built jellyfish, corals, and anemones
• Simple sea creatures may hold the secret to the first eyes
• The moon jellyfish genome reveals the ancient origins of our own complex nervous systems
• The tiny, armored architects of the ocean's hidden biodiversity
• Hydrozoa are tiny, predatory architects that build complex, interconnected living colonies in the sea.
• Soft corals are chemical factories producing life-saving compounds from the ocean floor
• The smallest animals on Earth are actually highly evolved, microscopic jellyfish relatives
• The stinging secret of nature's most primitive tissue-based animals

More in Cnidarians · More in Nature · Latest · A–Z · All topics