Sunday, October 25, 2020

Sharks Among Us… Is There a Danger?

STEPPING STONES


Hammerhead Shark Submitted Photos

Hammerhead Shark Submitted Photos

Not too long ago I wrote an article about some of the sharks found in our area.

Since then, I have been stopped many times by people requesting more information concerning the varied species found here and if there is any danger.

Let’s take a look at some of the findings.

First of all, are there sharks here? You bet! Are there as many as 25 years ago? No. Are we humans on the menu? Not intentionally.

The entire Gulf of Mexico region is home to nearly 50 different species of sharks. Some of the more common ones that we find in our immediate area are the Blacktip, Bonnethead, Great Hammerhead, Lemon, Nurse, Tiger and Bull Sharks.

Bull Shark

Bull Shark

Blacktips are common in Florida’s coastal waters, bays and estuaries. It migrates south during the winter months. Just recently a video of blacktips surfaced showing their migration northward, probably because of the abnormally warm February that we experienced here. Although they feed primarily on fish but can also make a meal of crabs, octopus, lobster, rays and even other smaller sharks. The female gives birth to live young, coming into the bays in spring and early summer. A litter will contain as many as ten pups. Fully grown they may reach ten feet in length.

The Bonnethead resemble the Hammerhead in physical appearance and are actually the smallest member of that family. They can be found very near shore, around sand bars and also in mud flats. Their dinner is comprised primarily of small fish and shrimp. They also give live birth with a litter of four to 12 pups on average. They only grow to about three feet.

 

 

The Great Hammerhead Shark is a migratory species that can be noticed in our area mostly during the spring and summer months. It feeds on stingrays, grouper, squids, crabs and other sharks. Also giving live birth, a litter may contain up to forty pups. This species can grow quite large, up to eighteen feet long, and some local fishermen have seen one in our area over the past few years that appears to be twelve to fourteen feet.

Lemon Sharks enjoys the shoreline but can be located in the estuaries and travels into fresh water as well. Its food sources are mollusks, rays, smaller sharks and bony fish. Giving live birth, a litter may have fifteen pups. The young will stay in the shallow estuaries and lagoons, using them as nursery areas until they are more mature. They grow to more than ten feet long.

The Nurse Shark prefers habitats like coral reefs, rocks and mangrove islands where they find their food supply of shrimp, crabs, sea urchins, squid and smaller fish. A litter can contain as many as fifty pups from a live birth. Maximum size for this species would be about nine feet. Juveniles will utilize grass flats and mangrove islands as their nursery.

Tiger Sharks are distinguished by the stripe-like features on its sides. They can be found in open oceans as well as shallow bays. The stomach contents of this voracious feeder has included sea turtles, a variety of fish, marine birds, conchs and many other aquatic animals. Live birth could result in as many as eighty pups. These predators can reach eighteen feet in length and nearly 2,000 pounds. Worldwide they are second only to Great Whites regarding attacks on humans.

Bull Sharks are an apex predator that not only inhabit near shore waters but have been known to travel well inland utilizing coastal river systems. Boasting a large menu these opportunistic feeders will eat sea turtles, dolphins, sharks, rays and sea birds. They also give live birth, producing up to a dozen pups. They can grow up to eleven feet long and are responsible for the third highest number of attacks on humans, behind Tiger sharks and Great Whites.

At this time of year we do seem to experience an influx of these predators. Talking with Rodger Parcelles, owner of Sunshine Tours at the Rose Marina, He tells me that the warm waters will bring the bait fish toward the shore and that, in turn, brings the mackerel, king mackerel and tarpon. This will attract the sharks. It is common to expect a number of Tigers Sharks, Blacktips, Lemons and Bull sharks in our waters over the next few months. The Bulls have been seen in Rookery Bay and as far into fresh water as Henderson Creek, near U.S. 41 and Collier Blvd.

So the second and third sharks on the list responsible for human attacks are here in our area. However, since records began in 1882 there have been zero fatalities in Collier County and only eight reported bites, most of them were cases of mistaken identity… there was no outright attack on a human because it was human. In the Collier, Lee and Charlotte County areas there are only seventeen recorded attacks in 136 years.

To boot, the shark population has declined in South Florida in the last three decades by 75%. Worldwide the number of sharks taken by fisheries exceeds 100 million each year.

Many people may think that the less sharks around, the better, but there is a food chain, an order to each ecosystem that provides a series of checks and balances. If sharks are not here to eat certain species of fish, that species now becomes over abundant, until its prey is no longer plentiful and the negative affect continues down the line. For example, if sharks are gone and the larger fish are too plentiful they will eat the algae-eating fish. If there are not enough algae eating fish that could be a problem for a reef and we just established nearly forty artificial reefs here in Collier County.

Understand your environment and appreciate the importance of every level of the food chain. Even the sharks are important to our pristine waterways.

Bob is the owner of Stepping Stone Ecotours, conducting walking tours of the western Everglades. He is also a naturalist for a local dolphin survey team on board the Dolphin Explorer. His latest book “Beneath The Emerald Waves” is a top seller by local authors. Bob loves his wife very much!

What: Bob McConville’s presentation on some of our area’s sharks.

Where: Rose History Auditorium, 180 S. Heathwood Dr., Marco Island

When: Monday, March 19 at 7 PM

Cost: MIHS Members free; Non-members $10

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