Species threatened by over-exploitation typically require conservation measure that either prevents or discourages harvesting or, promote sustainable use. Later may involve harvesting management or commercialization of fanned individuals.
Capture, sharing and release of wild Vicunas vicugna in southern Andes are an example of an ancient method of sustainable use. Many species may benefit from well managed programmes on non-consumptive uses, particularly tourism (e.g., marine turtles and gorillas) (McNeilage, et al. 2001). Over-harvesting deplete and sometimes causes extinction of species.
Extermination of American passenger pigeon (Ectopistes migratorius) is a classical example, out of 132 inventoried plants that local people use for traditional medicinal purposes in southern Cochabaniba (Bolivia), 10 were threatened because of intensive collection (Urena and Diversidad, 2001)
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Whiskery shark, Furgaleus macki, has been caught in commercial fisheries in Western Australia since 1940s. In early years, long line fisheries capture small number of shark. Introduction of multifilament gillnets in 1960s increased catches.
However, in mid 1970s, a reduction in catches occurred. Catches rose dramatically later with well equipped shark fishing vessel. In late 1970s and early 1980s, Whiskery Shark population reduced to approximately 30% of pre- harvest levels.
In mid 1980s, Western Australia introduced management to gillnet fishery, restricting levels of fishing effort and taking other management measures. Since then, sharks abundance has remained relatively stable at 30-40 % of pre- harvest over a period of 12 years (approximately two generations). Final phase of management measures was implemented in 2000/01.
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Significant and steady increases in species abundance in centre of its range for last 4-5 years are noticed. To ensure continued recovery of this stock, two month closure of significant portions of species range within target fishery are being considered to further reduce adult mortality.