Sandbar Shark

[Sam]

Sandbar Shark
Carcharhinus plumbeus
"aka brown shark, queriman shark, and thickskin shark. "

Description: The sandbar shark has a very high, nearly triangular first dorsal fin anterior or above the pectoral axis, whose height is as much as 18 percent of the shark's total length The snout is blunt and rounded and shorter than the width of the mouth. there is an inter-dorsal ridge between dorsal fins. The dermal denticles have no definite teeth and do not overlap as do most sharks from this family. This is a bluish brown gray with a light to white ventral. The tips and outer margins of the fins are often darker with no definite markings. The upper teeth are broad, serrated and triangular in shape. The lower teeth are narrow and serrated. Erect and symmetrical increasing smaller as they go toward the corners of the mouth. Sharks have between 5 and 7 gill slits on each side of their body in front of their pectoral fins. Bony fishes only have one pair. Having many exposed gill slits probably helps transfer more oxygen into their blood faster which allows them to swim very fast when they need to. Most shark's skin is covered in small denticles instead of scales. Denticles are are a lot like teeth. They have dentine in the center and enamel on the surface. This makes shark's skin very tough and abrasive (like sandpaper). The shape and position of some shark's denticles also helps reduce friction so that they can slip through the water easier.

Similar Fish: The dusky shark, big nose shark and bull shark are similar to the sandbar shark.

Where Found: The sandbar shark is a coastal-pelagic species that inhabits temperate and tropical waters. It is the most abundant species of large shark in the Western Atlantic. It has a global distribution, being found in the Western and Eastern Atlantic, the Indo-Pacific ranging from the Persian Gulf, Red Sea and South and East Africa to the Hawaiian Islands. The Revillagigedo and Galapagos islands in the Eastern Pacific is also home to the sandbar shark. This is a bottom-swelling shallow coastal water species not often seen at the surface of the water. It can also be found in harbors, the mouths of bays and rivers and estuaries with shallow fast moving water. It avoids freshwater, coral reefs and water with jagged or rough bottoms.

Size: This shark is fairly large and can reach 7 1/2 feet long and weigh as much as 200 lbs. The average male matures at a length between 4 1/2 to 5 ft and females mature at a length between 4 1/4 to 5 1/2 feet. The average male will weigh approximately 110 lbs and the females 150 lb

Bait used: Fresh fish, tuna belly

Tactics to catch: The Sandbar sharks are usually caught by long lines, but also with gill net as well as anglers using rod and reels

Climate (water temperature range): Subtropical; 23 – 27°

Spawning habits: The mating occurs in the early summer or spring in the northern hemisphere and in the southern hemisphere they mate in late October to January. The males are extremely rough and often leave scars between the dorsal fins where he bites her during courtship. Sharks and rays do not reproduce like other fishes. Most fish release clouds of sperm and eggs into the water column where they mix together. The fertilized eggs then float around until the fish larvae hatch and form schools of tiny fish. Male sharks have two organs called claspers attached to their anal fins. They insert one of these into the female shark's cloacae (the entrance to the uterus) to transfer sperm (just like in mammals). Some sharks and rays incubate the eggs in their uteruses until the baby sharks are ready to be born. The gestation period varies from 8 to 12 months. The Atlantic variety carry their young for nine months and can bear every other year. Births occur in shallow water to prevent adult (bull sharks) from preying on the young. The female shark can give birth to liters from six to thirteen pups. The young travel in schools when they late fall and return in the summer months repeatedly for the next four to five years. Later when they are adults they will travel much greater distances.

Table food? The sandbar shark is desirable for its fins, flesh skin and liver. Marketed fresh, smoked, dried-salted and frozen; fins are valued for soup). Also known to be used in Chinese medicine.

Consumption Concerns: Not recommended due to high levels of mercury.

Feeding habits: The sandbar shark is a bottom feeder that eats mollusks, crustaceans and small fish such as eels, skates, rays, dogfish, squid, octopus, bivalves, blue crabs, shrimp, shad, menhaden, barracuda, mackerel, grouper, croaker, flounder, stingrays and smaller sharks.bony fish. These sharks normally feed during the day, but are really active at night.. They are smart feeders. Sharks have an extra sense that is able to detect tiny electric fields. They can use this to find food that is buried or search for animals to eat in the dark or in turbid water.

Remarks: These sharks have a life span up to 21 years. The oil and leathery skin of these sharks are extremely marketable. Sharks and rays do not have true bones like other fishes. They have cartilage instead which is lighter and much more elastic and allows them to bend in very tight circles. Sharks do not have swim bladders. A swim bladder is a gas filled sack inside the body of bony fishes that allows them to stay still without sinking. Sharks compensate by having a very big liver that is filled with oil. Even so, sharks sink unless they keep swimming forward. A shark's upper jaw is not fused to its skull like most animals. When a shark bites a large object, it is able to move its upper and lower jaw forward in order to take a bigger bite. Unlike other fishes, sharks are able to replace their teeth constantly. New teeth grow from the inner surface of the jaw and rotate forward when the old teeth get worn out or lost during feeding.

References: Florida Museum of Natural History-Craig Knickle
Fish Facts
Dept of Health & Human Services
newenglandsharks.com

[mdram]

some shark identification links

http://www.capth3.com/public/sharkid.pdf

http://www.mrc.virginia.gov/vsrfdf/shark_links.shtm