page_title: Common thresher
section_title: Commercial fishing
hierarchical_section_title: Common thresher / Relationship with humans / Commercial fishing
caption_attribution_description: English: Common thresher shark (Alopias vulpinus) caught on a longline.
context_page_description: The common thresher, also known as Atlantic thresher, big-eye thresher, is the largest species of thresher shark, family Alopiidae, reaching some 6 m in length. About half of its length consists of the elongated upper lobe of its caudal fin. With a streamlined body, short pointed snout, and modestly sized eyes, the common thresher resembles the pelagic thresher. It can be distinguished from the latter species by the white of its belly extending in a band over the bases of its pectoral fins. The common thresher is distributed worldwide in tropical and temperate waters, though it prefers cooler temperatures. It can be found both close to shore and in the open ocean, from the surface to a depth of 550 m. It is seasonally migratory and spends summers at lower latitudes.
  The long tail of the common thresher, the source of many fanciful tales through history, is used in a whip-like fashion to deliver incapacitating blows to its prey. This species feeds mainly on small schooling forage fishes such as herrings and anchovies.
context_section_description: The common thresher is widely caught by offshore longline and pelagic gillnet fisheries, especially in the northwestern Indian Ocean, the western, central, and eastern Pacific, and the North Atlantic. Participating countries include the former USSR, Japan, Taiwan, Spain, the United States, Brazil, Uruguay, and Mexico. The meat is highly prized for human consumption cooked, dried and salted, or smoked. In addition, their skin is made into leather, their liver oil is processed for vitamins, and their fins are used for shark fin soup. The United Nations Food and Agriculture Organization  reported a worldwide common thresher take of 411 metric tons in 2006.
  In the United States, a drift gillnet fishery for the common thresher developed in southern California in 1977, beginning with 10 vessels experimenting with a larger-sized mesh. Within two years, the fleet had increased to 40 vessels, and the fishery peaked in 1982 when 228 vessels landed 1,091 metric tons. The common thresher population rapidly collapsed from overfishing, with landings decreasing to less than 300 metric tons a year by the late 1980s and larger size classes disappearing from the population. Common threshers are still taken commercially in the United States, with about 85% coming from the Pacific and 15% from the Atlantic. The largest catches remain from the California-Oregon gillnet fishery, which had shifted its focus to the more valuable swordfish (Xiphius gladius), but still takes threshers as bycatch. Small numbers of Pacific threshers are also taken by harpoons, small-mesh driftnets, and longlines. In the Atlantic, threshers are primarily taken on longlines meant for swordfish and tuna.
caption: The thresher shark is taken commercially by many countries. Here a common thresher is hooked on a longline
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot S60", "Image DateTime": "2006:03:16 15:26:03", "Image YCbCrPositioning": "Centered", "Image Tag 0x1001": "1600", "Image Tag 0x1002": "1200", "Image ExifOffset": "144", "EXIF ExposureTime": "1/80", "EXIF FNumber": "4", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2006:03:16 15:26:03", "EXIF DateTimeDigitized": "2006:03:16 15:26:03", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "101/16", "EXIF ApertureValue": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "4", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, auto mode", "EXIF FocalLength": "365/32", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1600", "EXIF ExifImageLength": "1200", "EXIF FocalPlaneXResolution": "1600000/283", "EXIF FocalPlaneYResolution": "300000/53", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}