997 resultados para scale insects


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This is the fourth River Dart Scale Reading Investigation Report on the 1965 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions.

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This is the fifth River Dart Scale Reading Investigation Report on the 1966 Season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions. It also compares the results of previous reports.

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This is the sixth and final River Dart Scale Reading Investigation Report on the 1967 Season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions. It also compares the results of previous reports and gives a full summary for the investigation (including previous reports).

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This is the first River Dart Scale Reading Investigation Report on the 1962 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews briefly the theory and mechanics of the scale-reading technique, the life history of the salmon, and the methods used for the collection of scales and the examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in various tables and figures are also included, plotting weight distributions for each age classes and frequency distributions.

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This is the second River Dart Scale Reading Investigation Report on the 1963 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are alo included plotting weight distributions for each age classes and frequency distributions. The report also remarks the similarity of the results with those for 1962.

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This is the third River Dart Scale Reading Investigation Report on the 1964 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are also included plotting weight distributions for each age classes and frequency distributions. After three years of the investigation a pattern is emerging which shows that the Dart salmon population is mainly composed of four year old fish, which have spent two years in the river and then two year or little longer at sea.

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This is the River Dart Scale Reading Investigation Report on the 1971 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. In 1967 the final report on a five-year scale reading programme was summarised, at the time it was considered sufficient information to help with restocking programmes and the management of salmon population. But a further scale reading programme was started in an attempt to monitor changing patterns in salmon runs that may be caused by the new influences. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are also included plotting weight distributions for each age classes and frequency distributions.

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This is the River Dart Scale Reading Investigation Report on the 1972 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. In 1967 the final report on a five-year scale reading programme was summarised, at the time it was considered sufficient information to help with restocking programmes and the management of salmon population. But a further scale reading programme was started in an attempt to monitor changing patterns in salmon runs that may be caused by the new influences. It reviews the methods used for collection of the scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the 5th Annual Report of the Rive Exe Scale Reading Investigation for the 1970 season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the 6th Annual Report of the Rive Exe Scale Reading Investigation for the 1971 Season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the 7th Annual Report of the Rive Exe Scale Reading Investigation for the 1972 Season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the Salmon Scale Reading Investigation from 1972 by Cornwall River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon populations of the River Tamar, River Tavy, River Lynher, River Fowey, River Camel and River Plym. It contains for each river the numbers of caught salmon, number of scales received and which were unreadable and percentages in each age group separately for net and rod caught. Length and weight frequency distribution histograms have been plotted to show the size distribution of the various sea age group.