One Fish, Two Fish, A Lot of Starfish!
The shorelines of South Carolina are teeming with starfish! Let’s dive in and learn more about starfish washing ashore, starfish biology, and the ins and outs of these 5-legged beauties! Watch the video here.
Tomato, Tomahto? Sea Star, Starfish?
Photo Source: John Lockett from the Sun
Fun fact: starfish aren’t actually fish, they are echinoderms! Most marine biologists refer to them as sea stars, but they can be called starfish or sea stars. They lack gills, scales, and fins. An echinoderm is an invertebrate that lives in the ocean and has a unique body shape. The word echinoderm means “spiny skin.” Sea stars, sea cucumbers, brittle stars, sand dollars, sea lilies, feather stars, and sea urchins make up the Echinodermata phylum.
Sea stars are extremely diverse; there are about 2,000 different species of them! Most of the time, they have five arms each with its own eyes at the tip.
Sea stars travel by means of their “tube-like feet” and use them for support. They have suction cups that help them grip to the ocean floor and move. If a leg is lost due to predation, damage, or the elements; it can regrow!
Sea stars, like other echinoderms, exhibit something called “radial symmetry.” This means that their bodies have symmetry around a central axis (dictionary definition). Starfish are found in a variety of habitats, but mostly in the intertidal zone. Other times, they can be found in the deep sea, rocky shores, kelp beds, tropical areas, or even colder regions of the ocean. Sea stars can have anywhere from five to 40 arms. The sun star is one example of a sea star that has up to 40 arms.
A New Level of “Nom Nom”
Sea stars are carnivorous, meaning they exclusively eat animals. They have an incredible way of hunting and swallowing their prey! Typical prey items they will hunt for are coral, sponges, clams, oysters, sand dollars, barnacles and mussels. On the edges of their arms, they have light-sensitive eyespots that aid in finding food. Once they’ve acquired their target, sea stars will actually extend their stomach out of their body! The stomach will stretch out of their mouth and cover the prey item. Since their stomach contains enzymes, these break down the tissue of their prey and allow them to bring it into their stomach for digestion. If the prey organism is small enough, starfish will just swallow them whole. YUM!
Sea Star Party in South Carolina!
Earlier this week, over 1,000 thousand starfish washed ashore of Garden CIty beach in South Carolina. During low tide, people had the pleasure of viewing all of these starfish washed ashore. Biologists suggest that the sea stars were following their prey items, barnacles and clams, into the intertidal zone and got left behind during low tide.
The sea stars’ ability to “walk” back into the ocean saved most of them during this phenomenon. Some beach guests interacted with the sea stars or put them back into the water themselves. In an interview done by Zach Wilcox advises beach enthusiasts to let the wildlife find their way back to the ocean and avoid disrupting their feeding behavior and schedule. This particular phenomenon of starfish washing ashore is normal and has occurred throughout history.
Getting Washed Up
Another famous occurrence of sea stars coming ashore happened in Ireland in 2012. There were an estimated 50,000 starfish that washed up that year! Marine biologists studied this event and have several theories for the cause of it. Some say that this is a result of stormy weather creating stronger waves that can dislodge starfish from their feeding grounds nearby. Others say that this could be a type of breeding behavior and that the congregation might have to do with the timing of year and breeding season. Additionally, fishing practices such as dredging may disrupt and uproot starfish causing them to lose grip of the ocean floor and get carried out to the shoreline. Jellyfish and Portuguese man o’ wars have been known to wash ashore, too, with change in the climate.
Sea stars are an important predator in ocean ecosystems. Their diversity in habitats and size help control the prey population and keep marine food chains in balance. As always, clean up trash, reduce waste, eat sustainably, and lower your carbon footprint to help these marine organisms thrive. They are truly stars of the ocean!
Thanks for reading our blog post. I hope everyone is having a beautiful summer and enjoying the ocean in any way that they can!
Written By: Bailey Higa