Starfish underwater

Starfish are marine echinoderms found in all oceans, with over 2,000 known species renowned for their regeneration ability and radial symmetry.

About this subject

Starfish, or sea stars, belong to the phylum Echinodermata, which includes sea urchins and sea cucumbers. They inhabit environments from intertidal zones to abyssal depths, adapting to substrates like rocks, sand, and coral reefs. Most have five arms, but some species can have up to 40. Their water vascular system, composed of tube feet, enables slow locomotion and prey capture, targeting mollusks and small crustaceans.

A remarkable feature is their ability to regenerate lost arms and, in some cases, an entire body from a single arm. This process may take months and is vital for survival against predators. Ecologically, starfish control populations of mussels and oysters, which can impact aquaculture. In Brazil, species like the green starfish (Linckia guildingii) are common along the northeastern coast.

Culturally, starfish symbolize renewal and are often used in coastal decor. However, overharvesting and pollution threaten their populations. Ocean warming causes mass mortality events, such as the sea star wasting disease affecting populations on the US West Coast. Interestingly, they lack a brain and blood, relying on a decentralized nervous system to coordinate movement and responses to stimuli.

Frequently Asked Questions

How many arms can a starfish have?

Most have five arms, but some species can have up to 40, like the sunflower sea star (Pycnopodia helianthoides).

Can starfish regenerate body parts?

Yes, they can regenerate lost arms and, in some species, even a whole body from a single arm.

Where are starfish found in Brazil?

They are common along the entire Brazilian coast, especially on coral reefs and rocky bottoms, with notable species like Linckia guildingii in the Northeast.