ISSN:
1439-0426
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Sturgeon (Acipenser sturio L., 1758) was a common species in the Guadalquivir River until the thirties. In 1932 a dam was built in the spawning area, 100 km from the river's mouth, that interrupted the migration. In the same year, a caviar and sturgeon smoked flesh factory started to run. By that time most of the fishes came to the factory from the dam area, but since 1934 the use of a fishing line without bait, specific for sturgeon catch, enabled fishermen to work in deep holes of the lower estuary. Using data from the factory records, we found that gravid females only got to spawning areas downstream of the dam when the water flow was greater than 100 m3/sec. Increasingly frequent dry weather in spring (caused by droughts and water regulation for flow irrigation) occurred, which led to persistent reproductive failures. During dry springs, it was more likely to catch sturgeons in the lower estuary than in the medium and upper estuarine areas, because fishes remained settled in deep holes, waiting for better water flow to continue their upstream migration. Increasing catches in this area resulted in the elimination of the most potentially reproductive adult fishes before they had any chance to spawn, which has finally led to the virtual extinction of the population.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1439-0426.1999.tb00222.x
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