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The article presents a reprint of the research paper which appeared in the Tweed Commissioners Annual Report for 1972 released in April 2, 1973. The paper reflects the results of the study on the growth of the 500 hatchery reared tagged brown trout with an average fork length of 25.0 centimeters which were released into the River Tweed, Scotland on March 29, 1972.

This paper reports a study of the damage done by rooks in agricultural land and of the effects of various methods of crop protection in an intensively cultivated area in Aberdeenshire, Scotland. Losses were high on early or late sown crops. Losses of yield were not directly proportional to the intensity of utilization owing to limited compensation. Losses to lodged grain were small, only a small proportion being attributed to rooks. Rook attacks on potatoes didn't significantly affect the yield. Other kinds of damage, which occur on a smaller scale, are described.

The article presents a questionnaire which aimed to evaluate trout angling potentials of fishing waters in Scotland. The paper served as an initial sifting process and was formulated base on some suggestions to increase the number of trouts for fishing by a countrywide survey of possible inlets. Some questions might appear irrelevant to the problem of assessing a trout fishery, however, the wash-in of organic matter and fertilizing chemicals around the land affected aquatic animals.

Eggs collected from around the base of cultivated cruciferous crops in north-east Scotland were hatched on suitable media contained in petri dishes, or on plants grown in pots in an outdoor insectary. Breeding in petri dishes was more successful. It was found that Erioischia brassicae (Bouché), the cabbage root fly, and E. floralis (Fall.), the turnip root fly, occur together in swede crops, but only E. brassicae in crops of cabbage and cauliflower. Despite the eggs of both species overlapping in size and the chorion patterns being indistinguishable, plotting mean egg sizes over short consecutive periods showed that the main egg-laying period of E. floralis was during August and September. The measurements of eggs collected before and after 1 August, when plotted on arithmetical probability paper, indicated an appreciable difference in the average size of eggs laid in the two periods, but only at those sites where both species were found. [ABSTRACT FROM AUTHOR]

The paper describes how absolute values of pollen deposition may be calculated from the results of volumetric sampling, supplemented by routine meteorological data. Daily mean values of concentration of birch pollen in the air at Lerwick, Shetland in 1970 and 1971 are presented, and these are used to calculate daily and annual depositions. The results are consistent with what is known about the occurrence of tree pollen in fossil and recent deposits in Shetland. [ABSTRACT FROM AUTHOR]

Electronic computers have enabled the quantitative relationships between stratigraphic variables to be calculated for a sequence of Namurian (El zone) cycles deposited in a differentially subsiding basin east of Stirling. Despite their limitations, coefficients of correlation and linear regression equations provide a relatively simple means of expressing the relationships between critical variables and so provide a useful way in which various cyclically deposited sequences can be compared. All possible pairs chosen from eleven variables are investigated, including the total number and average thickness of cycles, total number of coals and total thicknesses of coal, sandstone and shale. These six variables all tend to show a linear relationship with total thickness of strata and hence net subsidence. A second part of this paper, to be published later, will examine the relationships between variables in more detail, using the technique of factor analysis. Third-degree trend surfaces of six of the variables show regional patterns that suggest the interaction between two extreme types of sedimentation patterns termed basin patterns and wedge patterns. These are thought to be related respectively to net subsidence and relative nearness to the shoreline. Trend surface residuals reveal well-defined local geological features, including a trough-like depression, which was commonly occupied by channels carrying sand, trending southwestwards from near Saline.

The paper deals with sedimentary structures in shallow-water Precambrian deposits of Lower Torridonian age in the island of Skye in northwestern Scotland. The structures described include irregular lamination, ripple-bedding, festoon bedding and structures produced by local erosion and reworking. Evidence of penecontemporaneous disturbance thought to be due to the movements of quicksands is briefly referred to. Variations in lithology and structure within the succession are attributed to local differences in conditions within a possible environment of sedimentation in an intertidal zone with off-shore sandbanks. [ABSTRACT FROM AUTHOR]