Starfish, more accurately known as sea stars, are found in the waters surrounding Hawaii. This vibrant marine environment supports a diverse array of these echinoderms, contributing to the rich underwater ecosystems of the Hawaiian Islands.
Starfish Species in Hawaiian Waters
Hawaii’s waters are home to a variety of sea star species, with approximately 20 known shallow-water species and 68 deep-sea species identified. Among the more recognizable species is the Crown-of-Thorns starfish (Acanthaster planci), a large, multi-armed sea star covered in venomous spines. This species can grow up to 18 inches across with as many as 21 arms, and its body coloration often includes shades of red and green.
Another notable resident is the Blue Sea Star (Linckia laevigata), known for its striking blue coloration, which can range from deep royal blue to turquoise. This species typically reaches 10 to 14 inches in diameter across its five slender arms and is found throughout the Indo-Pacific, including Hawaiian coasts.
The Chocolate Chip Sea Star (Protoreaster nodosus), also known as the Horned Sea Star, is characterized by its light to reddish-brown body adorned with distinct black, conical protrusions resembling chocolate chips. It is found in Hawaii, where it can grow up to 12 inches in diameter.
The Cushion Star (Culcita novaeguineae), sometimes called the Hawaiian Sea Star, is known for its plump, cushion-like appearance and vibrant colors. It is often found around Oahu.
Habitats Where Starfish Thrive
Sea stars in Hawaii inhabit a range of marine environments, from shallow coastal areas to deeper offshore waters. Many species, including the Crown-of-Thorns starfish, are commonly found on coral reefs, where they can forage for food.
Other species, like the Blue Sea Star, thrive on coral reef flats, sandy bottoms, and in seagrass beds, typically at depths ranging from 3 to 100 feet. Some sea stars, such as Linckia multifora, prefer crevices on shallow reefs and areas under rocks on the reef flat, feeding on fine organic debris.
Certain sea stars are also found in soft sediment environments, such as sandy or muddy bottoms, demonstrating their adaptability to various substrates.
Ecological Significance and Threats
Sea stars play a significant role within Hawaii’s marine ecosystems, primarily acting as predators and scavengers. Many species contribute to reef health by consuming detritus, algae, or other invertebrates, helping to maintain ecological balance. For instance, the Cushion Star feeds on algae, which helps prevent overgrowth that could harm corals.
The Crown-of-Thorns starfish (Acanthaster planci), while a natural part of the ecosystem, can become a source of concern during population outbreaks. In such events, these sea stars consume large amounts of coral, potentially causing significant damage to reef structures. Hawaii has a Rapid Response Contingency Plan in place to address potential Crown-of-Thorns outbreaks, alongside other threats like coral bleaching and disease.
Beyond outbreaks, Hawaiian sea stars face challenges from climate change, including rising ocean temperatures and ocean acidification, which can disrupt their habitats and physiology. However, Hawaii’s isolated location has so far protected its sea star populations from widespread sea star wasting disease, a significant threat to populations in other parts of the world.