As we shark dive around the world we rarely have an opportunity to visit a shark research facility. Our two weeks on Bimini Island allowed us to photograph great hammerhead sharks, bull sharks, nurse sharks, blacknose sharks, Caribbean reef sharks, southern stingrays, and Atlantic spotted dolphins. What a fantastic diversity of big animals around a very small island. We got to see baby lemon sharks and nurse sharks at the Bimini Shark Lab.
The research they do here is invaluable. Sharks are under threat worldwide and research is needed to better understand them and protect their nursing sites. One thing that their research has revealed is that the female lemon shark returns to the same mangrove sites that they were born at to give birth to their pups. Knowing this allows researchers to influence governments to protect these critical environments.
We found it fascinating to go to their holding pen to see the young shark pups that they were doing research on. We photograph the adults in the oceans but never see pups. Young sharks reside in the mangroves skirting the islands for protection in their early years but at some point venture away from these safe zones. The shark pup with the barbels is a nurse shark and the other is a lemon shark. So neat to see such young, small sharks.
Bimini Island in the Bahamas is where these photographs were taken. It is a small island 80 km (50 miles) from the Florida coast and has a large variety of shark species. On this trip, we also encountered great hammerheads, nurse, blacknose, blacktip, and bull sharks. They are commonly found in shallow water around coral reefs.
Caribbean reef sharks (Carcharhinus perezii) are the most common requiem shark species encountered by divers in the Caribbean sea. They also inhabit parts of the Western Atlantic ocean. If you dive in the Caribbean you may encounter this shark as it is relatively common.
Most of the baited shark dives involve the Caribbean reef shark. This is often the first “shark dive” new divers will take part in and it can be thrilling. We did this years ago with our kids and I must say we were nervous and our adrenaline was sure flowing. However, this made us fall in love with sharks when we realized just how majestic they were. This surreal experience led us to pursue our “shark hobby” and we have been photographing them ever since.
They average about 1.5 to 2 meters (5-7 feet) in length but can reach lengths of about 3 meters (9 feet). They often hang out around Caribbean reefs and it is likely the largest shark you will encounter while reef diving. Their diet consists of a variety of fish, octopus and small rays.
Caribbean reef sharks can evert their stomachs which means the stomach is turned inside out. This is helpful to discard undigested food and plastic. Unfortunately, our oceans are now full of discarded plastic from human consumption. These plastics are often ingested by marine organisms and are responsible for many needless deaths.
Scuba diving in the dark is always an adrenaline rush because you know that there are sharks near you but you can’t see them until they suddenly appear. We love night dives because they add an entirely new dimension to exploring the underwater world. We photographed these great hammerhead sharks around Bimini Island in the Bahamas.
Sharks are very comfortable swimming in the water at night. To simplify, their eyes are designed to allow light to pass through the retina twice which enables sharks to see in the dark. It is believed that sharks can see about ten times greater than humans in clear water.
They also have a cephalofoil (the hammer) that is full of electrical sensors. These electroreceptors are interconnected jelly-filled pores called ampullae of Lorenzini and aid in hunting as these sensors pick up electrical signals given off by all living creatures including humans. Therefore, a shark at night is very aware of your presence and location in the ocean even though you have no idea where they are.
Most divers encounter southern stingrays (Dasyatis americana) buried in the sandy bottom during a dive in the open ocean. During our time on Bimini island in the Bahamas, we decided to snorkel around the shallow mangroves in search of juvenile lemon sharks. Mangroves are critical environments for juvenile fish and sharks because it acts as a nursery for many species. Protected from the predators in the open ocean these shallow waters with their massive root systems provide protection.
We didn’t find any sharks but we were surprised to see so many southern stingrays around the shallow mangroves. There is a relatively large population of great hammerhead sharks that inhabit these waters at this time of year. Because the main predator of these rays is the great hammerhead shark we wondered if they modified their behavior at this time of year to try to avoid these sharks.
When most people think of sharks, they think of species like the great white shark, tiger shark, and bull shark. These are known as requiem sharks and have that classic shark appearance. However, there a numerous species of shark that look very different from requiem sharks including the nurse shark (Ginglymostoma cirratum). These are very common sharks in the Caribbean and often encountered by new divers.
The head is broad with tiny eyes and has two barbels (whisker-like appendages) that are used in the search of food. Their teeth are small and designed for crushing as part of their diet includes eating shrimp, crab, and lobster. They are nocturnal and during the day they are often seen laying under ledges but are also seen in the open on the sand.
They are a fairly large shark and can reach over 3 meters or about 10 feet although most are much smaller. They can tip the scales between 90 to 115 kg (200-250 pounds). The gestation period for nurse sharks is about 6 months and generally, they have between 20-30 pups.
Although many divers see them as harmless, their mouth can produce a tremendous suction and could easily suck in fingers or a hand which they generally will not let go of. Therefore, like all sharks, they must never be touched and need to be respected.
Although we love to photograph all sharks, our favorite is the great hammerhead (Sphyrna mokarran). Generally, it is a cautious shark and will keep its distance from scuba divers. There are 9 species of hammerhead sharks worldwide but the great hammerhead is the largest. An average adult reaches lengths of about 3.6 to 4.3 meters (12-14 feet) but can reach 6 meters (20 feet) and exceed 550kg (1,200 pounds).
Great hammerheads are newer sharks on the evolutionary scale and have developed some unusual characteristics. The unique feature of this shark is obviously the head. The “hammer” which is called a cephalofoil is full of electrical sensors. These pores called ampullae of Lorenzini aid in hunting as these sensors pick up electrical signals given off by all living creatures including humans.
As you view these photographs notice how different the shark can look depending on the angle of the photograph. On a larger shark, the cephalofoil is about a meter (3 feet) in length and the eyes are at the ends which gives it a large range of vision.
The diet of this shark is diverse. They will feed on a variety of fishes including tarpons, porcupine fish and even other sharks. As well, lobster, squid, and octopus form part of their diet. However, their favorite food is rays. Stingrays bury themselves in the sand and the great hammerhead uses its cephalofoil with its electrical sensors to detect their location.