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Fish-weir
A fishing weir, fish weir, fishgarth or kiddle is an obstruction placed in tidal waters, or wholly or partially across a river, to direct the passage of, or trap fish. A weir may be used to trap marine fish in the intertidal zone as the tide recedes, fish such as salmon as they attempt to swim upstream to breed in a river, or eels as they migrate downstream. Alternatively, fish weirs can be used to channel fish to a particular location, such as to a fish ladder. Weirs were traditionally built from wood or stones. The use of fishing weirs as fish traps probably dates back prior to the emergence of modern humans, and have since been used by many societies around the world. History The English word 'weir' comes from the Anglo-Saxon ''wer,'' one meaning of which is a device to trap fish. A line of stones dating to the Acheulean in Kenya may have been a stone tidal weir in a prehistoric lake, which if true would make this technology older than modern humans. In Ireland, fish traps in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Trap BKG
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Most f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
