- Although the flesh of the almaco jack is considered quality table fare, the species has been associated with ciguatera poisoning, a seldom fatal stomach irritation.
- The almaco jack is susceptible to tapeworm parasites in the caudal peduncle area, but the meat can be eaten safely if affected portions are cut away.
Blacktip shark (Carcharhinus)
Blacktip sharks are members of the requiem shark family, which is the largest group of sharks. Their body shape and behavior match those considered by most people to be typical of sharks. With fins that have black tips, they are appropriately named. However, these black tipped fins also make it very easy to confuse them with the very similar blacktip reef shark.
The bodies of blacktip sharks have a dark color that may be dark blue-gray, dark gray, gray-bronze or gray-brown. The belly is a white to yellow-white color. There is a white band running along the flank, which helps a person distinguish these sharks from other sharks. The dorsal, pectoral, anal, and lower caudal fins have the distinctive black tips. Young blacktips are usually paler in color than adults. The first dorsal fin is relatively large, high, and located forward of or even with the trailing edge of the pectoral fins. The second dorsal fin is considerably smaller. The pectoral fins are also relatively long.
Blacktips have extended gill slits and lack an interdorsal ridge. The body of the blacktip shark ends with a long, narrow snout that is somewhat pointed and with a slight v-shape. They have several rows of sharp, serrated teeth that are replaced when lost or worn.
Although very similar to the blacktip reef shark, they are not the same shark. Blacktip reef sharks have a similar, but noticeably lighter coloring with a dark band on the flanks. In addition, the snout of the blacktip reef shark is shorter and more rounded. Finally, blacktip reef sharks have a larger second dorsal fin.
Blacktip sharks eat substantial quantities of food. Their quickness and well-developed sense of smell aid them in tracking schools of prey fish. Although they feed at a variety of depths, most feeding occurs near the surface.
A variety of small and medium fish make up this species diet, primarily herring, smelt, menhaden, sardines, anchovies, sea catfish, tongue-soles, threadfin, mullet, mackerel, butterfish and porcupine fish. When they choose to feed at the bottom they will also consume grunt, grouper, jack, porgies and snook. For variety, they will also eat various rays, octopus, crab and lobster. When food is scarcer, they will even eat small sharks.
Blacktip sharks are a widely distributed in tropical, subtropical and warmer temperate waters of the Atlantic, Pacific and Indian Oceans. They can be found in a majority of these waters between 45 north and 37 south latitudes. In the western Atlantic, they can be found as far north as Nova Scotia and as far south as southern Brazil. This area includes the Gulf of Mexico and the Caribbean Sea. In the eastern Atlantic their range extends from the Mediterranean Sea to Zaire.
In the eastern Pacific, blacktips can be found from Baja California to Peru and the Galapagos Islands. In the central Pacific they can be found in waters near Hawaii and Tahiti. In the western Pacific, they roam from China to Australia.
In the Indian Ocean, they are found from South Africa to India to China to Australia. This area includes the Red Sea and island areas like the Philippines, Borneo and New Guinea.
Blacktip sharks inhabit a variety of inshore and offshore environments and display a preference for clear water. Generally, they locate near continental shelves, drop-offs, areas of surf and near offshore structures. They can also be found occasionally near river mouths and estuaries, and in lagoons, swamps, and bays. They usually reside in waters less than 100 feet deep. Adult blacktip sharks tend to form schools of the same gender. The males will locate in cooler and deeper water than females. Young blacktips form mixed-gender schools and are often found in shallow waters near beaches.
- When blacktip sharks are near the surface, their dorsal fin may stick out of the water, a fin recognized by the average person as indicating the presence of a shark.
- There is quite an active commercial fishery for blacktip sharks. In addition to their marketable meat, the hides are sought after for leather; the liver provides a popular oil; and the fins also have commercial uses.
- Blacktips very seldom attack humans, and most of those are accidental on the part of the shark. However, they can be dangerous when provoked.