The West Coast Starry Flounder (Platichthys stellatus) is a flatfish that resides in cold water. They go by many different names, such as the grindstone fish, emery wheel fish, long-nosed flounder, rough jacket fish, diamond flounder, English sole, or swamp flounder.
These flounder have some unusual ways to hide from predators and are flexible in where they hunt for their prey.
To learn more about these dark flatfish that propel themselves through the water, read this article about the Starry Flounder.
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Characteristics & Appearance
The Starry Flounder is one of the odd flatfish that can only see on one of their body because of the placement of their eyes.
They can be left-eyed or right-eyed, but most of them are left-eyed. A fascinating fact since Starry Flounder technically belong to the right-eyed flounder family.
Weight & Length
The Starry Flounder can be as small as eight or nine inches long, while others can grow as massive as three feet long.
The average length that the Starry Flounder grows to is between ten and fourteen inches. The maximum weight of a Starry Flounder recorded is 20 pounds, but they often weigh closer to ten or twelve pounds.
Physical Characteristics & Color
The most notable characteristic of this flounder is their flat widebodies. They travel with their flat bodies perpendicular to the ocean floor to easily cut through the water.
An impressive feature of this fish is its ability to change color by altering the pigment granule concentration in its chromatophores.
The side of their body that they have visibility on is a dark brown color with some dark orange accents.
The dark brown color blends in perfectly with the muddy seafloor, making them excellent at camouflaging when predators are around.
The other side of their body, called their blindside, is typically a shade of white. The blindside is white because when they hide, it lays against the ocean floor so no predators can see it, and it won’t give away its position.
On their dorsal and anal fins, they have alternating colors of black and orange. The colors can confuse predators as they move through the water.
But on the other hand, these colors can make it harder for them to camouflage against the ocean floor.
Lifespan & Reproduction
The Starry Flounder lives a relatively long life for their size. Females usually live for 15-17 years, while males can survive for 25 years under the right conditions. The smaller fish tend to live longer, permitting predators don’t eat them.
Their spawning period runs from November to February. But they are most active during December through January, as they prefer colder water when fertilizing and reproducing.
Like many fish, they exercise external fertilization, meaning the eggs are laid and then fertilized by the sperm.
These fish do not usually lay eggs in deep water, sticking to the shores, riverbeds, and sloughs to keep their eggs safe from predators until they can hatch.
The Starry Flounder thrives in the dark, muddy parts of the ocean, where it can comb for food and hide from predators.
They can be just a few inches below the water’s surface near the coast or dive down as deep as 1,200 feet where the ocean floor is sandy and muddy.
They like sand, mud, and gravel because it allows them to hide at any given moment. While Starry Flounder are most common off the coast in the ocean, they can also survive in freshwater, which is a fascinating ability.
They typically avoid over-salinated water because their cells have trouble regulating salt levels in their body.
Where Do Starry Flounder (West Coast) Live?
The Starry Flounder population is primarily off the coast of California near Santa Barbara. They are abundant on the west coast of the United States, but they can live near Korea and Southern Japan throughout the Bering Strait. Sometimes they also move as far up the coast as Canada and Alaska.
Food & Diet
As discussed, the Starry Flounder can grow to be small or incredibly large. It is unclear what dictates the size a flounder will grow to and may be a genetic trait passed down from parents, like how some humans are 6 foot 5 while others are 5 foot 1. The size of the individual Flounder plays a significant role in their diet.
What Do Starry Flounder (West Coast) Eat?
Smaller Starry Flounder, usually under a foot in size, most commonly eat worms, crabs, clams, sand dollars, and brittle stars. They generally survive on planktonic organisms because they are easy prey.
These sea creatures are relatively small and can be found along the ocean floor or on continental shelves near beaches.
Usually, they move toward the shores as they run out of prey in the deeper parts of the ocean floor.
Larger Flounder, those around three feet in length, will feast on small fish such as sardines or sanddabs. Whichever kind of prey they go after, they usually find it by combing the bottom of the ocean floor with optimum stealth.
When they approach prey, they lunge, taking in a big gulp of water to trap the organism and bring them into their mouth.
Sometimes the Flounder will sit in one place on the ocean floor using their camouflage. They wait for prey to near them, and then they attack.
Threats & Predators
The Starry Flounder is relatively safe from predators and human threats because of its ability to camouflage itself against the seafloor.
Not only does its natural coloring help it blend in with mud and gravel, but it can change its coloring to mimic its environment, adding another level of stealth and protection.
Humans do not pose a significant threat to the species. They are well-managed in fishing because they are not in high demand commercially, as their flavor as a portion of food is rather unimpressive. However, they suffer from pollution and dumping in the ocean and along the shores.
Microplastics and other trash can enter their system or entangle them, so they suffocate. While pollution hasn’t had a massive impact on the species, there has been a decline in the population.
Climate Change & Global Warming
But they also mostly must live near shores to feed. As the oceans warm, the shores become the warmer waters, threatening the Starry Flounder population.
Predators of the Starry Flounder mainly include birds, marine mammals, and sharks. Because this fish swims so close to shore and has a blind spot, they are perfect prey for seagulls and often get scooped up and eaten.
They can usually avoid these predators by laying motionless on the floor. But if they get in their path, they’re almost sure to be eaten.
Aside from pollution, warming oceans, and natural predators, Starry Flounder, do not have many other threats.
One concern is the disruption of their habitat, but because they can thrive in both deep and shallow water, most of their habitats are undisturbed.
Although ocean warming poses a threat to the Starry Flounder species, as does pollution, the population is stable for now. They are classified as Least Concern mainly because they do not face the threat of overfishing.
Fun Facts About Starry Flounder (west coast)
- Technically, Starry Flounder don’t swim; they glide.
- They swim like other fish (vertically) when they are young and then switch to horizontal swimming when they sexually mature.
- They have the unique ability to swim backward, which many fish cannot do.
- Their scales look like tiny stars; that’s where they got their name!
- When they rest or hide on the ocean floor, their fins prop them up so their body never touches the floor.