Let’s talk sharks!

As I begin shore diving again this year and seeing quite a few sharks on first few dives, I decided it might be good to bone up a bit. Richard saw a 9 foot (ok, maybe it looked bigger under water) blacktip on a dive the other day off Vero Beach and I could clearly see a bit of fear. Thankfully, I missed this one but he freaked me out enough to get my curiosity going. I feel knowledge is key to understanding and over coming our fears.
With the movie Jaws, sharks get a bad wrap as being terrible killers. The fact is, that many shark could care less about you. If you see a shark, the best thing to do when you feel threatened when diving is get to the bottom. Richard and I stay together as we look like a bigger and more threatening object to them. I love swimming very near nurse sharks in the shallows!

There are about 21 sharks that you have the possibility of seeing when diving boat or shore in Florida but there are common ones you will see most often. I am going to start with these. I will point out that I have plenty of friends with boats that fish and many of these make tasty treats for dinner and serve up a divine dish when cooked on the grill with a little fresh mango, lime juice and coconut. It is a fabulous, meaty fish.

The most common are as follows: lemon shark, blacktip, shark, nurse sharks, bull sharks, Caribbean reef, mako sharks (off coast more in deeper waters), tiger sharks, hammerhead sharks and bonnethead sharks.
Click on any of the links and you will see full writeups as I fill them in and pictures to help you identify.

Description: These are brown with a yellowish hue on the underside. The first dorsal fin is short and not much larger than the second dorsal. The pectorals are triangular and wide. Will range 3-8 feet in length.
Size: From around 20 pounds to well over 100 pounds. The world record is 405 pounds and the Florida record is 397 pounds.

Description: These are gray above and white below. Tips of dorsal and pectoral fins are black, as is the lower lobe of the caudal fin. Short snout and stout body. Dorsal fin begins at a point above the rear portion of the pectoral fin.
Size: Common from 5-30 pounds; seldom reaches 100 pounds, but reported to 200 or more. World record 270 pounds, 9 ounces; Florida record 152 pounds. Blacktip sharks from average 3 to 6 feet but can grow to over 8 feet. They are your most common shark found on the shoreline. These guys get a really bad rap, causing many bites thinking a smimmer or surfer is a fish on the surface.

    Bull Shark

Description: Usually gray to light brown above, white below. Similar to the sandbar shark but has a shorter, wider snout. The large first dorsal fin starts above the middle of the pectoral fin, whereas in the Sandbar it starts above the front portion of the one pectoral.
Size: Commonly runs 6-8 feet and 100-200 pounds, but can exceed 10 feet and 400 pounds. World record 636 pounds, 14 ounces; Florida record 517 pounds.

Description: Most of the ones I have seen are grey and white. They can be brown or deep rust color. It has a very small, underslung mouth, and is the only shark with barbels at the nostrils. Nurse sharks have respiratory systems that can pump water over their gill slits. This allows them to breathe without moving. Look at the nurse shark’s fins. Instead of the pointy dorsal fins that we might see in movies when sharks swim near their prey, nurse sharks have rounded dorsal fins on their back, the first one bigger than the second. Nurse sharks have extremely long caudal fins(tails) which make up more than 25% of their total body length. The bottom fin, the pectoral fin, helps the nurse shark to hover, and sometimes even to “walk” along the ocean floor. This hovering motion sometimes proves useful to nurse sharks looking for a bite to eat.
Size: Most seen in shallow water are from 5 to 50 pounds, but they can grow quite large in deeper water. World record 210 pounds.

    Bonnet Head Shark

Description: The bonnethead is unmistakable because of its rounded or shovel-shaped head – not squared off or only slightly rounded as in the larger hammerheads. Color is usually a very light gray, appearing almost white in the water.
Size: Averages 2-5 pounds; occasionally tops 10 pounds. World record 23 pounds, 11 ounces.

    Hammerhead Shark

Description: Frequently identifiable by size alone. Small ones can be distinguished from the scalloped hammerhead by the rather flat frontal edge of the head, and by the rear edge of the pelvic fin, which is curved only in the great hammerhead.
Size: Commonly runs more than 500 pounds and sometimes as much as 1,000 pounds; possibly can reach one ton. Florida and world records 991 pounds.

    Tiger Shark

Description: Easily recognized by its pattern – and often by sheer size. Color is dark above, yellowish below. On smaller specimens, the darker markings take the shape of spots – hence the name “leopard.” The big ones become “tigers” as the spots grow and blend together into stripes. The patterns, however, do vary a great deal.

Size: This is the largest shark likely to be encountered by Florida anglers. Quite a few 1,000-pounders have been taken in the state, and the species probably grows to a ton in weight. World record 1,780 pounds; Florida record 1,065 pounds.

    Mako Shark

Description: The shortfin mako, shown here, is known to offshore anglers as, simply, “mako.” The longfin mako is less often caught. Both have a huge mouthful of bulging teeth that are long and pointed. The makos are blue above and white below.

Size: Range is 200-600 pounds, but both species can weigh more than 1,000 pounds. World record 1,115 pounds; Florida record 911 pounds, 12 ounces.

Did you know sharks are a vulnerable species?

    What makes them vulnerable? Well, to start, they grow slow some species take 12-18 years to mature. Sharks often reproduce every other year and have few pups per brood. (1-10 pups) They like the nursery to be in bays, estuaries, lagoons and reefs. Human pose a huge threat to their existance. Sharks get caught in gillnets, trawl nest and on hook and line. Larger tuna and other commercial game fish boats will leave them on deck till they are almost dead and then toss them back too dried and close to death to live. Asian markets also harvest them for their find which are a delicacy. Humans hunt and kill more than 100 million sharks each year!

    Sharks have some adaptations allowing them to be exceptional predators. They include:

    1. Electroreceptors that detect electrical fields due to the presence of prey.
    2. Ever find a shark’s tooth? They have teeth that are replaced throughout their life.
    3. They have highly sensitive smell receptors
    4. Eyes that adapt quickly to low light levels
    5. Lateral line receptors that sense movement in the water

    So next time you see a shark, no panic…deep breath and enjoy what you see.

About daniellesdives

diving enthusiast
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1 Response to Let’s talk sharks!

  1. Pingback: January Calendar of Sealife & Migrations for South Eastern Florida | Danielle's Dives Blog

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