Blacktip Shark – They must swim with mouth open or else!


This is one of the sharks you may encounter when snorkeling or diving. His latin name is Carcharhinus limbatus. This is a mean, nasty shark and I always avoid these and get to the bottom as quick as possible.

    Habitat:

This creature is common in Florida’s coastal waters, bays and estuaries. We have seen this many times shore diving in Vero Beach. They tend to be a very active, fast-moving shark that is often seen at the surface. The blacktip shark can be found from Massachusetts coast all the way down to Bahamas and Caribbean. They are mostly coastal fish but have been found offshore. The can be found in waters up to 30 meters like reef drop-offs, bays and lagoons. All of which, we have plenty in Florida. They hang around in schools close to shore when they hunt for Spanish mackerel.During migration, they form large schools. In general, these sharks do not swim deeper than 33 feet (10 m), but can be found as far as 250 feet (75 m) down. During the winter months, they head south towards deeper coastal waters. They have been seen leaping out of the water, like their cousin the spinner shark, and then spin around several times before dropping back into the sea. These fish also live in mangrove areas, moving in and out with the tide. Blacktip reef sharks even venture into fresh water but don’t swim too far in from the ocean. I do not think this is true as i was sitting on a pier at a local favorite restaurant in Port St. John on the Indian River and we have watched a huge black tip swim right by us. I would say this location is across two rivers from the ocean and at least 10 miles away from the actual beach on fast route.

    Feeding:

The blacktip shark love little schools of herring, sardines, menhaden, mullet, and anchovies. They will also go after snook, porgies, grunts, porcupine fish, catfish, grouper, triggerfish, jack and flatfish. They primarily feed on small fish but will also tackle another shark, some types or rays and skates, octopus and our crustacean friends…lobster and crabs. Blacktips attack schools of fish from below at high speed while snapping their jaws to capture prey. I watched a program on Discovery Channel, The Deep Seas(fabulous series with excellent videography) and these guys are fast. They featured the blacktips attacking a feeding ball of Spanish mackerel and they decimated it in no time. The shark attacks with lightning strikes which break small groups of fish out of the ball and then strike while they are separated. I have to say that I was cringing in my seat and awestruck at their precision and speed. Gave me a healthy respect for these dangerous guys!

    Features:

They have many features to help you identify them. The most obvious is the black tipped fins. They are a dark bluish gray with the young pups being paler above and white below. The have a very noticeable white stripe stripe on flank. The pectoral fin’s tip is conspicuously black.
The first dorsal fin, second dorsal fin, pectoral fins, pelvic fins, and lower lobe of caudal fin usually have distinct black tips. Please note however that on larger blacktips the tips may be faded or not visible at all. They do not have a mid dorsal ridge. The snout is long and almost appears v-shaped from below. It is moderately or sharply rounded and has a width length less than or equal to mouth width. The upper and lower teeth are narrow, erect and finely serrated and mostly symmetric. The body of the blacktip is dark gray, gray blue or gray brown above and white below. This is called countershading. There is a dark chevron-shaped band that originates near the pectoral fin and extends posteriorly. They average length is 8.25′. You can use the pale, or anal fin to spot the difference between a blacktip and a spinner shark.
They mature in 6-7 years and will be about 5′ in length. Scientists estimate that they live 10″ years.

    Other facts:

The Spinner Shark is similar but on the Spinner the 1st dorsal fin begins above a point behind the pectoral fin, and the snout is longer. The anal fins of the blacktip do not have any black tips whereas the spinner shark will often develop black tips on the anal fin as they mature.

They have been listed as vulnerable because more blacktip sharks are being caught than are replaced through reproduction. Like all sharks, blacktips have a very long gestation period and produce few young at a time. This makes it hard to replenish their population quickly.
Blacktip reef sharks must constantly swim with their mouths open, allowing oxygen-rich water to flow over the gills or breathing structures. These gills are a identifiable feature and are located in five separate slits on each side of the head. Since sharks don’t have a swim bladder like bony fishes, they will sink to the bottom if they stop swimming.

The blacktip reef shark is not considered to be a huge threat to people, even though they often swim up into the shallow waters where there are many snorkelers and scuba divers. This is good news to me!

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About daniellesdives

diving enthusiast
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