Echinoderms
Sunflower sea star
Pycnopodia helianthoides
Epipelagic zone
One of the largest starfish in the world, able to move surprisingly fast thanks to more than 15,000 tube feet, but today decimated by over 90% by a mysterious disease.
🗺️ Geographic range
Pacific coasts of North America, from Alaska to Baja California.
📊 Population
Population decimated by more than 90% since 2013 by a mass wasting disease; listed as critically endangered by the IUCN in 2020, one of the fastest population collapses ever documented in a marine invertebrate.
⚠️ Threats
Sea star wasting disease
A still poorly understood disease has wiped out more than 90% of the population since 2013, one of the fastest collapses ever documented in a marine invertebrate.
Source: IUCN — Red List of Threatened Species
Habitat
- Pacific Ocean · Kelp forest / seaweed meadow · Epipelagic zone · Permanent
🥚 Reproduction
External fertilisation, high fecundity.
Behaviour
- Diet
- Sea urchins, molluscs, other starfish: a voracious, fast-moving predator.
- Hunting
- Active pursuit at a speed unusual for a starfish.
- Communication
- None.
- Social life
- Solitary, essentially a hunter.
Physiology
- Anatomy
- Up to 24 arms, more than 15,000 tube feet in total.
- Respiration
- Dermal gills.
- Vision
- Eyespots at the tip of each arm.
- Adaptations
- A record movement speed among starfish, over a metre per minute.
⚡ Its extraordinary abilities
- Can have up to 24 arms and more than 15,000 tube feet
- One of the fastest starfish known, over a metre per minute
🏆 Records
One of the fastest documented population collapses in an echinoderm
More than 90% of the population wiped out since 2013 by a wasting disease.
Source: IUCN — Red List of Threatened Species
If you cross paths with this animal…
Risk: None.
Behaviour: Active, a key predator of sea urchins on Pacific coasts.
Advice: Critically endangered since 2013, a victim of a mass wasting disease.
💡 Did you know?
- Has lost more than 90% of its population since 2013 due to a still poorly understood disease.
- Its disappearance has fuelled a boom in sea urchin populations, threatening kelp forests.
