Shark, thresher

(Alopias spp.)

(Bonnaterre, 1788); / Alopias pelagicus Nakamura, 1935; / Alopias superciliosus (Lowe, 1840); / Alopias profundus Nakamura, 1935; ALOPIIDAE FAMILY; also called longtail thresher, pelagic thresher, Atlantic bigeye thresher, Pacific bigeye thresher, fox shark, sea fox, swiveltail, swingletail, thrasher shark.

The pelagic thresher shark, A. pelagicus, and the Pacific bigeye thresher, A. profundus, are found in the northwestern Pacific Ocean. The Atlantic bigeye thresher, A. superciliosus, occurs in the Atlantic. The longtail thresher, A. vulpinus, is found worldwide in warm to cool temperate zones. They are generally pelagic though they do come in close to shore. The longtail and pelagic threshers occur near the surface and the bigeye threshers inhabit deep waters, their large eyes undoubtedly aiding them in seeing at greater depths.

They are easily recognized because the upper lobe of the tail is usually as long as the rest of the body (appreciably longer in A. vulpinus). The caudal peduncle lacks keels, the teeth are small and pointed with broad bases, and the skin is smoother than that of most other sharks. The longtail thresher and the pelagic thresher have moderate sized eyes (1.2 1.5 percent of the total body length). The first dorsal fin is located almost squarely in the middle of the back, well forward of the origin of the pelvic fins. The Atlantic and Pacific bigeye threshers have much larger eyes (2.8 4.1 percent of the total body length) and the rear margin of the dorsal fin is located at least as far back as the origin of the pelvic fins. The belly and lower flanks of thresher sharks may be mottled.

Threshers are a solitary species but it is not uncommon for them to congregate when large schools of bait fish are available and occasionally hunt in pairs. Their diet is known to include mackerel, menhaden, garfish, needlefish and bluefish. Typically a thresher will slap or thrash the water with its tail to herd bait fish into a mass then use its tail to stun or injure individual fish before swallowing them. An angler may see his bait slapped out of the water then swallowed as it settles back in again, which is why threshers are often hooked in the tail. They are very active fighters when hooked and the longtail thresher has been known to leap clear of the water. Fishing methods include trolling in marlin fashion or deep trolling or drifting, depending on the species to be caught. Whole baits, strip baits, live yellowtail, snapper, or mullet may be used as well as feathers, or other baits or lures which are generally used for marlin or tuna.

They are ovoviviparous and give birth to 2 to 4 large babies, about 5 ft (1.5 m) long. There is no record of a thresher shark ever attacking a person, though there are cases of threshers attacking boats. The flesh is of good quality but is more often used as bait or chum to catch other sharks than as food

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Current All Tackle Record

767 lbs. 3 ounces.

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