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Fun Fish Friday

Fun Fish Friday - The Seahorse

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Fun Fish Friday - The Seahorse

Now that the excitement of summer camp is over, we think it's time to reinstate Fun Fish Fridays. This week we are going to learn about a very unique fish that doesn’t look much like its cousins – the seahorse. That’s right, the seahorse is actually a highly modified fish in the class Actinopterygii, or ray-finned fishes. The seahorse belongs to the genus Hippocampus, which literally translates from Ancient Greek to “horse” (hippos) and “sea monster” (kampos). This horse-like fish is prevalent in the waters around Sanibel and Captiva; we actually have 3 species that inhabit the region: the dwarf seahorse, lined seahorse, and longsnout seahorse.

The dwarf seahorse (Hippocampus zosterae) is common in the seagrass beds in Florida and throughout the Caribbean. 

Let’s start with the basics. Seahorses have the same basic fins as most other fish: a dorsal fin and paired pectoral fins. However, instead of a caudal fin (tail fin) the seahorse has an elongated, prehensile tail that it uses for stabilizing itself in the ocean currents. It wraps its tail around seagrass or coral and hangs on tight, helping it save energy for other uses. We've even observed a seahorse catching a ride on an arrow crab's back!

Notice the curved prehensile tail of this lined seahorse (Hippocampus erectus). This species can grow up to be almost 6 inches!

Like many other fish, seahorses are voracious, carnivorous predators, but because they have no true stomachs, they have to constantly eat to meet their energy requirements. Some seahorses may consume up to 3,000 brine shrimp in one day!  To chow down on so many crustaceans, they have a specialized mouth. Their jaw is fused, creating a straw-like shape that enables them to ambush and quickly slurp up their prey.

One of the seahorse's favorite meals, the brine shrimp, is an aquatic crustacean that is only slightly related to true shrimp. 

There is one aspect of a seahorse’s life that differs quite drastically from other fish. When seahorses are ready to reproduce, the male and female engage in an elegant courtship dance to seal their bond. Soon after, the female deposits her eggs into the male’s brood pouch where they are fertilized and incubated for up to 25 days. The male will then give birth to hundreds or thousands (depending on the species) of baby seahorses that are miniature copies of the adults. Scientists aren’t exactly sure of the biological advantages of Mr. Mom, but one theory is that it could allow the female to begin producing eggs as soon as she delivers her last batch to the male. Check out the courtship dance of one of the seahorse's closest relatives, the Weedy Seadragon:

Because seahorses are so unique and sensitive to environmental changes, scientists are studying them to better understand how to improve the overall health of our oceans on a global level - find out more here: http://seahorse.fisheries.ubc.ca/why-seahorses

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Fun Fish Friday - Atlantic goliath grouper

What animal is as large as a refrigerator, spotted and striped, and enjoys dining on spiny lobster? That’s right – The Atlantic goliath grouper! This fascinating giant is next up in our “Fun Fish Friday” series because they are one of our favorite fish here at Sanibel Sea School. Here’s why:

Atlantic goliath grouper are huge. As their name suggests, these fish can reach lengths of 8 feet and weigh up to 800 pounds – that’s about 100 pounds per foot! These hefty fish aren’t afraid to use their size to their advantage either. By contracting the muscles around their swim bladder, they are able to stun their prey with a sonic blast. In addition to lobsters and other crustaceans, they like to chow down on octopus, small sea turtles, and stingrays. Goliath grouper also have 3-5 rows of teeth that aren’t used for chewing, but instead for catching prey and keeping it in their large mouth!

A SCUBA diver with a goliath grouper.

A SCUBA diver with a goliath grouper.

Grouper (and their cousins the sea basses) have a unique characteristic to their family in which they spend part of their life as both male and female. This is called sequential hermaphroditism. When environmental cues are just right, female grouper transition to male, but we aren’t positive when exactly this occurs during development, or why. Once the males and females mature, a massive offshore spawning of over 100 individuals occurs where eggs and sperm are released into the water for fertilization.

Due to its popularity as seafood and as a target for sportfishermen, the Atlantic Goliath Grouper declined rapidly in past years, and is now a federally protected species listed as “Critically Endangered” by the World Conservation Union. It is illegal to harvest this fish and if accidentally caught, it is to be returned quickly and unharmed to the sea. We are optimistic that these strict regulations will bring the population numbers of these outstanding fish back up, so that we can enjoy their beauty for generations to come. 

A small goliath grouper caught (and promptly released) by a Sanibel Sea School staff member!

A small goliath grouper caught (and promptly released) by a Sanibel Sea School staff member!


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A great white weekend!

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A great white weekend!

Blog post by Caitlin Smith and Leah Biery

Duunnn dunnn... duuuunnnn duun... duuunnnnnnnn dun dun dun dun dun dun dun dun dun dun dunnnnnnnnnnn dunnnn…. Betsy!

If you’re a local, you’ve probably heard the news - a great white shark named Betsy “pinged” about 70 miles off the coast of Sanibel last Friday – around 10 PM on the night of April 25th!

Betsy is a 12’7” 1400 pound immature female white shark. She was originally tagged off of Cape Cod in August of 2013. Since being tagged almost a year ago, she has traveled out into the Atlantic and then moved down the coast and around the bend of Florida. Betsy has traveled over 3492 miles altogether in a year. White sharks can swim up to 35 mph, but normally cruise at much slower rates. Betsy is the first tagged white shark to be tracked in the Gulf. 

Betsy is a 12’7” 1400 pound immature female white shark. She was originally tagged off of Cape Cod in August of 2013. Since being tagged almost a year ago, she has traveled out into the Atlantic and then moved down the coast and around the bend of Florida. Betsy has traveled over 3492 miles altogether in a year. White sharks can swim up to 35 mph, but normally cruise at much slower rates. Betsy is the first tagged white shark to be tracked in the Gulf. 

As far as scientists know, great whites only occasionally visit the Gulf of Mexico, usually preferring cold waters inhabited by large marine mammals. So the ping was an exciting story in itself, but things get even more curious. The next day, a group of divers spotted and captured video of a great white about 80 miles offshore from Sanibel. But it wasn’t the same shark! The great white spotted by divers did not have a tag, which means there were two sharks roaming the same general area over the weekend.

Watch for a Sanibel Sea School guest appearance!

So the big question: are great whites more common in the Gulf than we thought? Maybe – it could be that they’ve always been here and we just didn’t see them often. The development of new tracking technology and a growing number of divers with cameras could lead to more verifiable sightings.

An alternative hypothesis is that the oceans aren’t as healthy as they used to be, so the sharks are expanding their range to search for food. It’s hard to say, but the events of the weekend pose many interesting questions about these powerful and fascinating creatures for scientists to examine in the near future.

We’ll be sure to keep our readers posted on the latest research – and please let us know if you hear anything interesting related to this topic!

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Fun Fish Friday - Atlantic Tarpon

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Fun Fish Friday - Atlantic Tarpon

At Sanibel Sea School, we love to teach people about the sea – and all of the creatures that live in it! So starting today, we are going to dive a little deeper into the realm of ichthyology by exploring some our favorite fish in our “Fun Fish Friday” series.

To kick off the series let’s talk about one of Sanibel’s local legends - the stunning Silver King, more formally known as the Atlantic Tarpon (Megalops atlanticus).  This majestic giant can weigh up to 280 pounds and may reach lengths of 8 feet! Not only is this fish the size of a small shark, it also puts up a pretty mean fight – that’s why it is one of the most popular game fish here in Florida. The tarpon singlehandedly brings in $174 million per year in The Everglades National Park and The Florida Keys Flats fisheries, and we don’t even eat them! That’s a pretty good financial incentive to protect their habitat.

Tarpon are fish on the move. They spend the winter in the toasty Caribbean waters and migrate to Southwest Florida when temperatures rise. Avid anglers pine away for the first full moon of the spring because that means the tarpon have made their journey back to our inshore waters. Around Sanibel and Ft. Myers, you can commonly find tarpon in San Carlos Bay and in the Caloosahatchee River, and fishermen close behind.

As if tarpon weren’t cool enough, they also have the ability to use their swim bladder as a lung, an organ usually used by fish as a buoyancy control device. Tarpon normally use their gills to obtain oxygen from the water, but when they live in more anoxic environments, such as freshwater ponds or The Everglades, they are able to take a big gulp of air at the surface of the water to fulfill their oxygen needs.

And while we’re on the topic, join us in wishing Doc Bruce, Ben Biery, Elizabeth Farnham, and Caitlin Smith luck in the J.N. “Ding” Darling & Doc Ford’s Tarpon Tournament next weekend. All of the proceeds from this tournament directly support efforts to conserve our marine ecosystem in the “Ding” Darling wildlife refuge. Find out more about the Tarpon Tourney here


Did you know that scientists are able to analyze DNA of a tarpon by taking a small skin sample? The Florida Fish and Wildlife Conservation Commission has created a citizen science project to better understand the tarpon population in Florida. By obtaining a tarpon's "fingerprint", scientists are able to determine how far and where they travel during migration. You can take part in this important research by acquiring your own DNA sampling kit  here . 

Did you know that scientists are able to analyze DNA of a tarpon by taking a small skin sample? The Florida Fish and Wildlife Conservation Commission has created a citizen science project to better understand the tarpon population in Florida. By obtaining a tarpon's "fingerprint", scientists are able to determine how far and where they travel during migration. You can take part in this important research by acquiring your own DNA sampling kit here


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