Strand Feeding Dolphins of Hilton Head Island
On Hilton Head Island, there are many opportunities to view wildlife in all its beauty and wonder. Nothing, however, compares with getting an opportunity to witness bottlenose dolphins strand feeding along the shores of our waters.
What is Strand Feeding?
Dolphins are well-known for their complex social behavior and intelligence. Both these traits can be seen exhibited through an amazing hunting technique known as “strand feeding.” It involves herding fish up onto a mudflat in the shallow waters around low tide. Working together to corral the fish into tight groups, the dolphins then turn into the school of fish, creating a massive force of water, pushing themselves and the fish onto the mudflat. They then use their rostrum (beak) to pluck individuals out of the group and swallow them whole. Once they have eaten the fish stranded on the shoreline, they then wiggle themselves back into the water, regroup and do it again.
The few. The proud. The strand feeders.
While its estimated we have a couple hundred resident dolphins that live here full time around Hilton Head, not every dolphin will learn strand feeding as a hunting technique. While both males and females can strand feed, it’s thought the majority of the strand feeders will be female. Visual observations have shown females strand feeding in small groups while their calves stay near observing the action, learning. Even within the female population, its estimated less than 20% will learn strand feeding as a hunting technique.
Where to find the strand feeders?
Those dolphins that do strand feed are quite selective on where to do it. Conditions have to be just right. The tide must be low enough to limit fish from escaping back into deeper water. The mud flats have to be the proper angle; too steep and the fish will be able to roll back into the water. Too flat and the dolphins risk getting themselves stuck on the shoreline. Our tours have had the best luck finding them in the smaller creeks that lead to the Calibogue Sound.
Right side only!
Dolphins that strand feed will only do so on the right side of their bodies. This brings up some interesting points and some questions that scientists are still working on. Dolphins don’t have the jaw strength to chew their food, so when they feed, the eat things they can consume whole. They do, however, need their teeth to capture their prey. While strand feeding, dolphins are taking in mud, shells, and bits of cordgrass and detritus. These things can damage their teeth over time and wear down the enamel, rendering them useless to grab things over time. Dolphins appear to be aware of this. By strand feeding strictly on one side, they only risk damage to that side of their mouths, leaving a perfectly intact side of teeth to catch prey in the open water.
Why they choose the right side over left is still a mystery to science. It could be a choice due to physiological makeup of the location to the air passage within the blowhole in relation to the pharyngeal aperture within the pharynx that allows them to swallow, or some other anatomical limitation that makes the right side a more preferable feeding side. There are still many things we don’t know about dolphins.
How can you see dolphins strand feeding?
Here around Hilton Head Island, the best way to see dolphins strand feeding is by boat. While we offer Private Dolphin Tours throughout the day, the best opportunity to find strand feedings are at departure times just before dead low tide. Feel free to call us at 843-247-8117 to coordinate an outing to coincide with the tides.
Strand feeding is truly one of the most remarkable feats in nature to witness. To see the coordinated effort put on by these beautiful creatures is something you must see to believe. If you have an interest in seeing dolphins strand feed on Hilton Head Island, or just want to get out on the water and see the amazing wildlife our island has to offer, get in touch with us to reserve your private boat charter today!
Things to do on Hilton Head when it rains
Hilton Head is full of things to do outdoors. Beautiful beaches, bike trails, golf courses and boat rides are all major reasons why it’s such a popular tourist destination. But there are some days the weather doesn’t quite work out the way we’d like.
Don’t let a rainy day spoil your trip! There are plenty of things to do even when the weather runs foul. Here are a few ideas.
The Beaufort County Library has a Hilton Head location on the north side of the island. Nothing beats curling up with a good book on a rainy day! The spacious building houses a children’s storytelling area, cozy South Carolina Reading Room, and the popular Friends of the Library Bookstore. Residents and vacationers alike are welcome to come see what they have to offer. Open year round, closed on Sundays.
If you have little ones that need to keep their hands and minds busy, you should head over to The Sandbox, an Interactive Children’s Museum. Let the imaginations fly in the children’s flight simulator, find their inner Picassso in the Rhythm and Hues art room, or become one with nature in the Loggerhead Sandcastle room. Hours of entertainment are here, right near Coligny Beach.
Spend some time exploring the history of the island at the Coastal Discovery Museum. While a good portion of the museum’s exhibits are outdoors, there are some amazing indoor exhibits that include the geological and historical development of the island. Check out some of the live animals in the Discovery Lab or immerse yourself in the local culture with one of the many rotating exhibits that focus on art, history and environment. Kids can get an opportunity to meet Myrtle the Turtle, a diamondback terrapin that resides in the Kid Zone! Located in Honey Horn on the north side of the island, the CDM is a must visit rain or shine.
Ever done battle with robots? Gone hang gliding over an island? Maybe you want to create a magical beast for a pet? If you’re looking for a little excitement in your afternoon, check out Atomic VR HHI, the only virtual reality arcade on the island. With over 30 games to choose from, there’s something for everyone to enjoy. Located near the airport, sessions range from 40 to 130 minutes and are suitable for ages 6 and up.
If you enjoy solving puzzles, head on over to the Hilton Head Escape Room. You’ll have an hour to work on this interactive adventure as your team is locked in a themed room. You’ll work together following evidence and discover clues in order for you to find the way out! Located near Coligny, you could easily find yourself spending the whole afternoon trying the various themed rooms.
Have a Beverage and Relax
Another great way to spend a wet couple of hours is to spend it at Park Plaza Cinema. A family owned, dog friendly (under 20lbs) movie theater, Park Plaza offers several films, comfortable seats, and an extensive food and drink selection. Showtimes and listings vary at this south located cinema, off Greenwood Drive near the Harris Teeter shopping center.
If it’s just adults in the group you can visit 3 spots of locally made beer, wine and spirits. Hilton Head Brewing Company, Hilton Head Distillery and the Island Winery are all located on the same street on Cardinal Road. Offering group tours and tasting, the Distillery gives you an in depth look at what it takes to make premium hand-crafted spirits, walking you through the entire process. Get a taste and a bite at the island’s first brew pub or get a flight of small batch wines at the Winery. 21 and over.
If the rain carries on into the evening, head on over to the Comedy Magic Cabaret. Known as fun, family oriented entertainment, the Cabaret has been keeping smiles on faces for almost 10 years. Friday nights is their wildly popular comedy game show “BONK” that’s as much fun to watch as it is to play. Centrally located on William Hilton Parkway, reservations are required.
Dolphins are already wet!
One of the great things about Hilton Head is the weather. While it may rain, it doesn’t usually rain all day. It often comes in small cells and doesn’t last too long. If it’s a little rain, we’ll still go out on the water to look for dolphins. Believe it or not, dolphins don’t mind getting wet! Give us a call to see what the day looks like!
These are just a few ideas of what to do while you’re waiting for the sun to come back out. There are countless more options on Hilton Head and its surrounding area you can find. Hopefully the weather cooperates with your vacation, but don’t let a little rain put a damper on your plans to explore.
I don’t think anyone’s ever written a riveting story about grass, but if you were, you’d have to make sure the type of grass is worth talking about. The spartina grass we have that’s found in our salt marsh definitely fits this bill.
Formally called sporobolus alterniflora, and known as smooth cordgrass, it’s the basis of our marine food web. While few organisms actually eat the grass while its alive, plenty of creatures need it for their continued growth and survival.
SURVIVAL OF THE FITTEST
How tough does spartina grass have it? Well, consider the obstacles it goes through for survival.
First, spartina is a freshwater plant that lives in saltwater. When faced with an submergence of saltwater, most freshwater plants would perish, but spartina has a trick up its sleeve. Through a process of desalination, the grass draws in saltwater through its roots, “sweats” out the salt, and retains the fresh water. If you were to look closely at a spartina stalk, you’d see salt crystals along its stem and leaves.
Because the marsh is inundated with saltwater from tidal flooding, the soil itself has very little oxygen in it. In the soil exists bacteria that actually creates its own oxygen to survive, and in the process emits a byproduct, hydrogen sulfide, that permeates the soil. At low tide you can actually smell this rotten egg scent.
But this hydrogen sulfide presents another challenge to spartina’s survival. High concentrations of hydrogen sulfide are highly toxic to all plants. Spartina is no different here, so why does it flourish here? Well, the plant has an ingenious solution.
Spartina has hollow air tubes that run from the top of the stalk down into its roots. The tubes draw oxygen from the air, down its stem and to the roots, which release the oxygen directly into the soil. This oxidizes the hydrogen sulfide in the soil immediately surrounding the root system, converting it to iron sulfate, which is a non-toxic sulfur. As the roots grow, this little bubble of iron sulfate enriched soil expands, protecting the plant!
SPARTINA: PROTECTOR OF THE LOW COUNTRY
So why is spartina so important? As mentioned before in a previous post, we have really, really high tides. When we have an incoming tide, the grass is almost fully submerged. This allows juvenile fin fish, shrimp larvae and small crabs to use the salt marsh as a nursery. Hiding in the spartina gives these young organisms a chance for survival from predation. It is estimated that over 70% of all commercial seafood caught off of the coast of the United States will have spent some portion of their lives in these nurseries.
Another reason for their importance is as an erosion barrier. The spartina lines the tidal creeks of the salt marsh and runs all the way to the tree line. The seasonal storms we have can bring significant waves and tidal surges. This grass is a first line of defense to absorb wave action and diffuse it before it reaches the land.
A FOOD SOURCE FOR MANY
Like all things living, spartina eventually dies, but even in death, the grass brings an abundance of life.
The dead spartina grass, called wrack, eventually makes its way out of the marsh on a high outgoing tide. It gets washed out of the creek, out into the sound, and eventually out into the Atlantic Ocean. While this is going on, the grass is decaying into detritus. Small microorganisms called phytoplankton will feast on the detritus. The abundance of feeding phytoplankton bring in zooplankton and small fish to feast on them, and in turn, larger organisms like fin fish, crabs, rays and dolphins eat the smaller creatures.
GRASS AS A BEACH BUILDER
And just when you think the grass couldn’t do any more, it has one last role to play. As it floats around the Atlantic, much of the wrack eventually finds itself along our beaches. Here it performs its second duty of an erosion barrier as the wrack breaks down into smaller fragments. It blends in with our fine sand, reinforcing the beaches, creating sand dunes and berms. The dunes then become annual nesting sites of sea turtles! Loggerheads, greens and leatherbacks all make appearances every year laying thousands of eggs right here on Hilton Head.
From the salt marsh, to the waterways, to our beaches. Spartina plays an irreplaceable role in the ecology of our island. Without it, we wouldn’t have the diversity or the beauty we often take for granted. Such a simple stalk of grass that does so much to bring life and protect it. As far as grasses go, spartina is indeed pretty cool. While on your next dolphin tour, you can appreciate all that the spartina does for us.
Healthy waters are a staple of healthy island life. While visiting the Island, a lot of visitors will ask about the quality of our water. They see its brown or green coloration and think it must not be very clean. There’s a natural inclination to see something murky as unhealthy. Not only is our water healthy, but its some of the cleanest sea water you’ll find on a coastline! The murkiness you see comes from two things; how much life is in the water and what attracts that life into the water; our mud.
From dirty pluff mud comes clean water
Pluff mud is a goopy mixture of soil, dead animal and plant matter. The majority of that dead plant matter is the spartina grass that lines our salt marsh. Pluff mud packs down densely, and doesn’t allow oxygen to permeate below a few inches of the surface. Any type of bacteria that survives in the mud has to create its own oxygen and you can actually smell this chemical reaction at work. As the bacteria create oxygen, they emit a by-product into the air, hydrogen sulfide, giving it a distinct aroma. Many people are convinced its smells like rotten eggs.
The pluff mud lines the bottom of our tidal creeks and its top layer is constantly moving with the strong currents we have here around the island. This primordial soup of nutrients is continually being kicked up and swirled about, never quite getting a chance to settle. As the current moves at its maximum speed churning up the mud, our waters turn a very ruddy brown coloration. This is the predominate color over winter as cool temperatures control the growth of microorganisms.
The Phytoplankton Cometh
Inside the pluff mud is a large amount of decayed animal and plant matter. This organic material is called detritus. Detritus breaks down in the salt water and allows microscopic algae known as phytoplankton to feed. These guys are tiny. We’re talking a fraction of a millimeter in length. As the phytoplankton eat the detritus, they release oxygen into the water. Warm temperatures and increased sunlight contribute to their growth. During the hot summer months the amount of phytoplankton increases and, while you can’t see them individually, you can see the effects of the colony. A large phytoplankton bloom will turn the water a greenish color.
Clean Water via the Food Web
Is all this algae bad? While some areas of the country face environmental catastrophes due to algae blooms, we don’t have that problem here. There’s a delicate balance to maintain and the salt marsh does an amazing job of regulating this by creating a food web. The algae that feeds off the detritus in turn becomes food for our oyster beds. Oysters are constantly filtering the waters here, collecting phytoplankton, other algae and bacteria and pushing out clean sea water.
Other organisms that eat phytoplankton, include zooplankton. Grass shrimp larva, cannonball jellyfish and sea roaches are common examples. They are voracious eaters, taking in as much phytoplankton as they can. In turn, bait fish, shrimp, crabs, and mobula rays make their way here and feed off zooplankton. These animals will continue the food web, as larger fish, sharks and dolphins will eat the smaller creatures. The fecal waste of all the animals go back into the water, becoming detritus, feeds the phytoplankton, and the cycle repeats itself over and over.
Keeping a balance for clean water
It’s important to have a balance within our water column. Any loss of one organism can have profound and devastating effects on the entire ecology. Loss of oyster habitat, overfishing or taking undersized fish out of the food chain all contribute to the decline to our water quality. Fishing restrictions include time, size and quantity give a species a chance to grow and repopulate without human interference. On land, building restrictions are in place to limit the amount of harmful pollutants entering our creeks and rivers. Without these regulations, we run the risk of becoming another environmental catastrophe.
While the waters here may not be crystal clear, you can be assured that they are healthy and clean . The next time you’re out on a dolphin tour exploring the waterways, you can be thankful that our murky waters bring so much life to our island.
Tides and Currents
Mobula Rays of Hilton Head Island
Hilton Head Island is a well known place to see dolphins in the wild. But did you know we also get an influx of manta and mobula rays coming into the waterways every spring and summer?
Mobula Ray or Manta Ray?
There was a time that manta and mobula rays where considered separate families. It was only within the last 10 years that scientists had realized they shared the same genus. All mantas have now been reclassified into the mobula genus, making them the largest of the mobulas rays. The largest mobula, the giant oceanic manta, can grow up to 3600lbs and have a wingspan of 29 feet. Here on the island we can regularly see the Atlantic devil rays, with a wing span of 4 feet, and occasionally the reef manta, that can exceed 15 feet. Over the past few years several large reef manta have been spotted along the coastline. This video was taken just off of Hilton Head!
Aside from size, another way to tell the difference is mouth placement. A reef manta’s mouth opening will be at the top of its head, directly between its feelers. An Atlantic devil ray’s mouth will be slightly lower.
Intelligence of Mobula Rays
But how smart are these creatures? Mobulas have the largest brains out of all fish, with developed areas for problem solving, communication, and learning. They’ve also passed what’s known as the mirror test, meaning they have the ability to identify their own reflection and have a greater likelihood of being self aware. Studies have shown mobula can also identify individuals within a group (specific humans for example) and react accordingly.
Another example of their intelligence is shown through their hunting techniques. Different from most other rays, mobulas are filter feeders, collecting zooplankton with their cephalic feelers into their mouths as they swim along. One such hunting pattern is with a large group of rays, they will begin to furiously swim in circles, actually changing the flow of the water and trapping the plankton inside the vortex they create. They’ll then line up, three at a time, one above the other, and enter the water vortex, mowing down the captured plankton. Very few animals have the knowledge and ability to change their own living environment for their benefit.
While the water here is a bit murky, you can still see these beautiful creatures in action. As the spring waters warm up into the early summer, we get an acrobatic treat from these rays. On any given day on the sound, the mobulas will launch up and out of the water, some somersaulting, some belly flopping, others doing a semi graceful swan dive. Why they do it is still a mystery to scientists. One theory is that the acrobatics are part of a lengthy mating ritual.
The females release a pheromone into the water that drives the males crazy and a chase begins. More males will join in the chase, forming a train of rays, one following the other, following the female. This can go on for several days. Over time the competing males will lose interest until only one is left. Whether this popcorning action of jumping out of the water is the female garnering their attention or the male showing off their prowess is unknown, but it does provide for a spectacle show.
Future of the ray
Information on mobula rays is still limited, but numbers suggest their population is going down. While their only natural predators are large sharks and killer whales, human interference plays a pivotal role in their livelihood. Overfishing, pollution and the effect of by-catch all play a pivotal role in their decline. Locally, there had been recorded documentation of large reef mantas roaming the Port Royal Sound 200 years ago. Unfortunately, these recordings also documented the hunting of these gentle giants with harpoon simply for sport. The rays we see today pale in size and number compared to the written testaments of the fishermen from the 18th century. Mantas are now a protected species in the United States with the hopes that the protection will give them a greater chance of survival.
Click here for our tour schedule, if you want to get an opportunity to see the mobula rays. Make sure to keep your eyes out on the water for these amazing creatures. You can be rewarded with a magical display at any given moment.
If you have any personal requests or questions about any of our tours, please feel free to reach out by phone, text or email(843) 247-8117