Lemon Sharks at The Island School

A couple of days ago, we set an anchor off the island of Eleuthera in the Bahamas. There is a school there called the Island School and the Cape Eleuthera Institute. The Island School is a lot like HMI in that high school students come for one semester and do their junior year while engaging with the outdoors. The biggest difference is that the Island School is on an island and they learn about the ocean instead of being in Leadville and learning about the mountains. And the Cape Eleuthera Institute is where researchers research a bunch of reef fish. I had a really fun time visiting both the Island School and CEI.

On one of the days, we went with some CEI people who are studying lemon sharks. The trip started when we saw a cooler with two lemon sharks in it being loaded onto one of the boats. They were babies, almost one year old and were each about 1 1/2 feet long. We got in the boat and, with the other 5 people, we went out of the small Island School marina. We zipped along to a creek surrounded by mangroves. 

Four adults, including Daddy, got out of the boat and went to set up a net to catch fish and sharks. The researchers were trying to catch new sharks to tag and study. Meanwhile, Porter and I sped away with Ian and Jeff, two of the researchers, to release the baby lemon sharks. The ride was bouncy and water kept leaking out of the cooler that held the baby lemon sharks. Jeff had to put his feet on the cooler to stop water from getting out and every once in a while, we would slow down and Jeff would change the sharks' water. The ride was about 30 minutes of bashing to windward. We learned about the lemon sharks and set them free. Lemon sharks go into a catatonic state when they are held upside down on their backs. Ian picked up one at a time out of the cooler with his bare hands, holding the shark upside down so that it would go limp, and then he carefully set them down into the deep water next to the boat. The lemon sharks must have been pretty happy to be in the real ocean because they immediately shot away. 

While Ian was holding the shark, he taught us a little about them. All lemon sharks have a scar on their chest. This is the umbilical cord scar, basically the lemon shark's version of a belly button. We could easily see the scar on the one Ian was holding. 

Lemon sharks are born alive in a group of 4-18 pups. The first born ones try to eat the next ones. They eat one another for a better chance of survival. Lucky my brother doesn't think this way! The surviving baby lemon sharks then go to the nursery waters. They live in the nursery waters, which are a flat and shallow expanse of water near mangroves, until they are 5-8 years old. They live there because it provides safety from predators, and has baby prey such as small snapper and grouper. They grow to be seven feet long on average by the time they leave the nursery waters and are fully in the mating stage. Only about 30% of the lemon sharks survive to this stage in life when they move to deeper areas near coral reefs. 

Ian explained to us that a shark gets sore easily after exercising. Slow, every day swimming is no problem but darting tires them out quickly. When you scare them, they dart and use a lot of energy. If you catch a shark, they will tire and possibly die. 

The top half of the lemon shark's tail fin is long. When swimming, the shark moves its tail fin back and forth, which pushes the shark slowly forward. In order to dart, the shark would flip its tail back and forth quickly and then straighten it out, letting itself glide through the water. Its pelvic fins are on either side of its tail and body. They are for stability. Its pectoral fins are the the big flat ones up front. They make the shark go up and down. 

This is a picture of two lemon sharks in a tank at CEI. These two are babies. And you can see what lemon sharks look like and where their fins are.

Ian let me rub my hand across the shark's flank. I was surprised to find that when I rubbed my hand one direction, the skin was smooth while the other direction was rough. This decreases the friction between the shark and the water so that it can swim more efficiently and more in control. 

Learning about the lemon shark was pretty cool. I think learning about them was a great way to have school. It sure beat sitting around in a classroom. I might want to go back to the Island School when I am in high school to do more activities like this one. -Jack Rabbit