Intensive fishing

Gdthberg A. 1983. Intensive fishing — a way to reduce the mercury level in fish. Ambio 12 259-261. 

Masson S, Tremblay A. 2002. Effects of intensive fishing on the structure of zooplankton communities and mercury levels. Sci Total Environ 304 377-390. 

Surette C, Lucotte M, Doire J, Tremblay A. 2003. Effects of intensive fishing in three natural lakes of northern Quebec, Canada, J Phys IV, Proc I2th Intemat Conf on Heavy Metals in the Environment 107 1443. 

Surette C, Lucotte M, Tremblay A. 2006. InUuence of intensive fishing on the partitioning of mercury and methylmercury in three lakes of Northern Quebec. Sci Total Environ 368(1) 248-261. 

Verta M. 1990. Changes in fish mercury concenhations in an intensively fished lake. Can J Fish Aquat Sci 47 1888-1897. 

From a far distant and evidently richer part of the world, Wheeler (1953) surveyed the commercially important bottom fishes of a number of banks in the Mauritius-Seychelles area. He demonstrated that measures of abundance of these fishery stocks depend on the kind of gear fished. Thus fishing with a series of drifting lines arranged in a row 40 feet wide yielded catches ranging from 2.1 to 48.4 tons of bony fish per square mile plus 5 to 84.3 tons of sharks. Fishing with nets on an offshore bank (the Soudan Bank) indicated that the annual yield would become stabilized at around 83 tons per square mile after a year of intense fishing. 

The enumeration of Enterobacteriaceae and Escherichia coli in water using SPC has been the subject of several studies. These microorganisms serve as indicators of faecal contamination as part of the monitoring of the quality of raw and partially purified waters. They are also used to demonstrate the compliance of a final product with legal standards. For the selective detection of viable Enterobacteriaceae, Baudart et al. (2002,2005) used a nucleic acid probe targetting the 16S rRNA. In order to enumerate the viable cells and to increase the fluorescence intensity, FISH was combined with a DVC procedure and TSA. Using this approach, as little as one fluorescent target cell could be demonstrated in the presence of lO -lO non-fluorescent other cells. 

At that time the spineback was not fished either in the delta or in the sea. Spineback resources in the Aral Sea were largely exhausted in the prewar years as a result of epizootia (in 1936) caused by suckling parasites and intensive fish catches before the river mouths. To ensure preservation of the spineback population, which was one of the most valuable fish species in the Aral Sea, its fishing was prohibited and it was caught only occasionally by seines in the delta. 

In developed countries, as well as in many developing ones, intensive fish firming dependent on industrial feeds is becoming increasingly important This evolution requires scientific and technical data ever more precise and diversified. Another aspect of aquaculture concerns the large number of fish species firmed, as more than 200 species are currently raised worldwide. 

BROMAGE N (1988) Propagation and stock improvement, in Shepherd J and Bromage N (eds). Intensive Fish Farming. Oxford Blackwell Science, pp. 103-153. 

To change the foodweb so that the concentrations decrease in fish. This applies to intensive fishing (Gothberg 1979) and nutrient addition (foremost of phosphorus in low-productive lakes see Hakanson 1980 Andersson et al. 1989). These measures are intended to stimulate the primary and secondary production. However, to make a detailed study of the flow of Hg and Cs in nutrient chains has been outside the scope of this project. 

Lake liming + intensive fishing. This measure is intended to increase pH, reduce highly Hg-contaminated fish, and modify the fish population and predation pres-... 

Intensive fishing (without liming) The intensive fishing resulted in reductions of 2.6 to 17.6 kg fish per hectare. Mainly pike were removed, but also perch, roach and other species. 

Fig. 9.3. A. Comparison of how the different remedies (LL=lake liming, WZZ= wetland liming, DAL=drainage area liming, 5e=selenium treatment plus liming and 7F=intensive fishing) influenced the percentage change of Hg-concentration in 7+ perch before time of the introduced remedy (tO-data) and up to 1989...

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