Sea stars, also known as starfish, can be fierce predators, depending on the species. They typically feed on mollusks such as clams, oysters, and mussels, using their suction cup-like tube feet to pry open the shells of their prey. Some sea star species have also been known to feed on small fish, crustaceans, and even other sea stars.
Some sea star species, such as the sunflower sea star, can have an important role in controlling the population of certain types of prey, thus maintaining the balance of the ecosystem they inhabit. Sunflower sea star was once a very common species in the Pacific Northwest, but a disease outbreak in the early 2000s caused a steep decline in population and thus, in the absence of this predator, the population of their prey, such as sea urchins increased and caused severe damages to the kelp forest.
Sea stars rival polar bears as top predators
A recent study published in Ecology and that LiveScience writes about took a deep dive into the Arctic coastal marine ecosystem and made a shocking revelation – the sea stars, which are often overlooked, are just as fierce predators as polar bears in these environments. By analyzing the food chains around Southampton Island in Canada’s Hudson Bay, the researchers discovered that the benthic (bottom-dwelling) part of the ecosystem has just as many intricate connections as the pelagic (open water) part and that sea stars play a crucial role as top predators in the benthic food web.
The research team meticulously went through data on 1,580 individual creatures residing in the Southampton Island coastal ecosystem to construct a new food web. Researchers found that benthic and pelagic ecosystems both have a similar number of steps in their food chains, and sea stars were key predators in the benthic web. One family of sea stars, Pterasteridae, was consistently at the top, feeding on secondary consumers such as bivalves, sea cucumbers, and sponges.
However, it’s important to keep in mind that not all sea stars are predators; some species are filter feeders, meaning they feed on small planktonic organisms.