Animal field guide
Japanese Sea Nettle
Chrysaora pacifica
Japanese Sea Nettle teaches Coastal Bloom in the bays of Japan and Korea, where a jellyfish barely 20 cm across becomes, for part of every summer, the most abundant animal in the water.
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Get AnimalDexJapanese Sea Nettle at a glance
Animal · Native range keys: north_pacific · Uncommon
Known for: Pale bell marked with sixteen radiating brown, Bell typically around 20 cm across, Long, Appears in dense seasonal aggregations in coastal
Understand the animal
Understand the Japanese Sea Nettle
Factual biology first: what this animal is like, where it lives, how it survives, and why those traits exist.
01
Introduction to Japanese Sea Nettle
Japanese Sea Nettle teaches Coastal Bloom in the bays of Japan and Korea, where a jellyfish barely 20 cm across becomes, for part of every summer, the most abundant animal in the water.
How to identify a Japanese Sea Nettle
- Pale bell marked with sixteen radiating brown stripes
- Bell typically around 20 cm across
- Long, fine tentacles trailing well beyond the bell
- Appears in dense seasonal aggregations in coastal water
Why Japanese Sea Nettle are interesting
- The radiating brown stripes on the bell are the quickest way to tell it from other sea nettles.
- It occurs in coastal waters around Japan and Korea.
- Its sting is painful to swimmers and it is a familiar summer nuisance on some beaches.
- Bloom size varies enormously from year to year with water temperature and currents.
- Like other sea nettles it alternates between a drifting medusa and an anchored seabed polyp.
02
Adaptations and biological abilities
03
Why does Japanese Sea Nettle behave this way?
- Pale bell marked with sixteen radiating brown stripes
- Bell typically around 20 cm across
- Long, fine tentacles trailing well beyond the bell
- Appears in dense seasonal aggregations in coastal water
Japanese Sea Nettles pulse steadily around the clock, drifting with tide and current rather than resting.
04
Why Native range keys: north_pacific?
Habitat: Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
Native range: Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
Native range
Natural range, not this specific capture location.
Some regional overlays are unavailable in this web build.
Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
05
Why this diet?
Zooplankton, fish larvae and other small drifting animals taken on stinging tentacles. This diet supports Coastal Bloom because a dense bloom can only form where plankton is dense enough to feed it.
06
Activity, rest, and lifespan
Japanese Sea Nettles pulse steadily around the clock, drifting with tide and current rather than resting.
The medusa stage lives for months at most, while the polyp on the seabed persists for years, holding the population between blooms.
07
Japanese Sea Nettle reproduction
Medusae release larvae that settle as polyps, and those polyps bud off young jellyfish when conditions turn favourable. Offspring fit the principle because the polyp waits, then releases many at once.
Male and female medusae are outwardly identical. Nothing distinguishes them because a bloom reproduces by broadcast rather than by pairing.
08
Predators, threats, and defense
Sea turtles, ocean sunfish and some fish that take jellyfish. Its answer is numbers and a strong sting rather than any individual defence.
09
Conservation and rarity
Rarity: Uncommon · 58/100. AnimalDex canonical rarity score: 58/100, maintained by the live indexed species profile.
- Observe from a respectful distance and avoid changing the animal's behavior.
- Do not block feeding, shelter, nesting, or travel routes.
- Use a live camera capture without handling or staging wildlife.
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Ask about its biology, behavior, abilities, survival strategy, symbolism, or what its strategy can teach you. Answers stay grounded in this species page.
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Where to find them
Where to find Japanese Sea Nettle
To find Japanese Sea Nettle in the wild, focus on the exact habitat patches that match its body design and daily behavior, not just the broad country where it exists. You usually do better by working one good piece of habitat inside native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate. than by covering too much ground.
- Headlands, reef edges, island colonies, tidal channels, or productive coastal water
- Protected habitat blocks within native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
Animal field guide
Japanese Sea Nettle
Japanese Sea Nettle teaches Coastal Bloom in the bays of Japan and Korea, where a jellyfish barely 20 cm across becomes, for part of every summer, the most abundant animal in the water.
Native range
Natural range, not this capture location
Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
Search near meAnimalDex stats
Dominance
28
Speed
12
Size
16
Intelligence
6
Rarity
58%
Total
120
Size scale
Scientific name
Chrysaora pacifica
Category
Animal
Habitat
Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
Rarity
Uncommon · 58/100
Native range
Native range keys: north_pacific, east_asia. Warm coastal bays and inshore water around Japan and Korea suit Japanese Sea Nettle because Coastal Bloom depends on shallow, enclosed water where numbers can concentrate.
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