Are There Starfish in the Tropical Ocean?

Tropical oceans are found throughout the world in a band stretching around the earth between the Tropic of Cancer to the north and the Tropic of Capricorn to the south. The central Pacific and Atlantic Oceans reside within the tropics, as well as most of the Indian Ocean. Tropical oceans support many types of marine life, especially in and around coral reef formations and tropical upwellings, currents commonly found on the west side of tropical continents.

  1. Sea Stars

    • Sea stars are often called starfish, but they are not actually fish. Fish have vertebrae and fins, while sea stars have neither. Sea stars are echinoderms, a Greek word for "spiny skin." Echinoderms, including sea stars, are radially symmetrical, meaning they have many appendages protruding at equal distances from the body. Sea stars belong to the group Stellaroidea, which is divided into two subgroups. True sea stars and sun stars belong to the group asteroidea, which has a distinguishing feature of connected arms. The arms of the subclass Ophiurodeas are not connected to each other but extend individually from the body.

    Habitat

    • Tropical oceans have incredibly temperate climate. Water temperature normally exceeds 68 degrees Fahrenheit and remains fairly constant year round. There are around 2,000 types of sea stars found in all three types of ocean: tropical, temperate and polar. Most sea stars dwell in the tropical regions near coral or rock formations. Their tentacles possess hundreds of small tube feet tipped with suction cups that help them cling to the hard surface and withstand strong ocean currents. Some tropical sea stars live in shallow, sandy areas. These sea stars do not have suction cups on their tentacles, but instead have a special type of exoskeleton which helps them filter sand from their gills.

    Anatomy

    • Sea stars typically have five arms but some species can have from 10 to 40 arms. Sea stars can regenerate lost limbs and some can even grow an entirely new body from just a small portion of an arm because all vital organs are housed within their arms. Sea stars move by filling their feet with sea water. The feet expand as they fill, and muscles retract the feet, allowing them to move around.

    Tropical Types

    • The crown-of-thorns is one of the most distinctive tropical sea stars because of its large size and sharp spines protruding from its body. Crown-of-thorns sea stars can quickly overtake a coral reef because of their capability for prolific breeding. The Blue Star is usually a variation of blue but can be aqua, purple or orange. Blue Stars are found throughout the tropical Indo-Pacific region. The Horned Sea Star is also called the Chocolate Chip sea star because of the dark-colored knobby protrusions on its skin and is found throughout tropical oceans from the South Pacific to Eastern Africa.