The Windermere perch and pike project: an historical review

This paper is an attempt to set the background, provide a brief history, review some of the Windermere perch and pike project's scientific achievements, note current developments and hopes for the future, and comment on some aspects of such long-term projects. The project was originally started in 1939 in order to provide fish in freshwater lakes which might be harvested to enhance the supplies of food in a country subject to blockade. Pike traps and gill-netting were trialed as fishing methods. Catch statistics are available from 1939 which can be used to study population dynamics or for modelling purposes. The author provides an overview of changes in the population dynamics of perch and pike but covers briefly other species like arctic charr and brown trout. Also covered are several aspects of the basic biology and ecology of the principal species involved.

Littoral vegetation of Lake Tohopekaliga: community descriptions prior to a large-scale fisheries habitat-enhancement project

An extreme dry-down and muck-removal project was conducted at Lake Tohopekaliga, Florida, in 2003-2004, to remove dense vegetation from inshore areas and improve habitat degraded by stabilized water levels. Vegetation was monitored from June 2002 to December 2003, to describe the pre-existing communities in terms of composition and distribution along the environmental gradients. Three study areas (Treatment-Selection Sites) were designed to test the efficacy of different treatments in enhancing inshore habitat, and five other study areas (Whole-Lake Monitoring Sites) were designed to monitor the responses of the emergent littoral vegetation as a whole. Five general community types were identified within the study areas by recording aboveground biomasses and stem densities of each species. These communities were distributed along water and soils gradients, with water depth and bulk density explaining most of the variation. The shallowest depths were dominated by a combination of Eleocharis spp., Luziola fluitans, and Panicum repens; while the deeper areas had communities of Nymphaea odorata and Nuphar luteum; Typha spp.; or Paspalidium geminatum and Hydrilla verticillata. Mineralized soils were common in both the shallow and deep-water communities, while the intermediate depths had high percentages of organic material in the soil. These intermediate depths (occurring just above and just below low pool stage) were dominated by Pontederia cordata, the main species targeted by the habitat enhancement project. This emergent community occurred in nearly monocultural bands around the lake (from roughly 60–120 cm in depth at high pool stage) often having more diverse floating mats along the deep-water edge. The organic barrier these mats create is believed to impede access of sport fish to shallow-water spawning areas, while the overall low diversity of the community is evidence of its competitive nature in stabilized waters. With continued monitoring of these study areas long-term effects of the restoration project can be assessed and predictive models may be created to determine the efficacy and legitimacy of such projects in the future.

Analysis of a concrete arch highway bridge reinforced with structural steel

An article in the Engineering News-Record for March 30, 1923, describes a new concrete arch bridge across the Connecticut River between Springfield and West Springfield, Mass.

Report on the Linda Vista bridge site

The Linda Vista Bridge spans the Arroyo Seco about a quarter of a mile above the Colorado Street Bridge, but serves an entirely different territory; as there is no road between there on the west bank. Los Angeles, Hollywood, and several of the beach cities can be reached by the way of the Colorado Street Bridge. The Linda Vista Bridge carries the traffic to the northwest of Pasadena, that is, Flintridge, Linda Vista, Montrose, Sunland. After leaving the bridge, the road follows the west bank of the Arroyo almost to the mouth of the canyon; then to the west along the foot of the mountains and into the San Fernando Valley.

The design of multimesh, multidepth gillnet fleets for use in the Lake Victoria Fisheries Research Project

Multimesh, multidepth gillnet fleets are useful in assessing fish stock abundance, size distribution and depth distribution. Using data collected on net mesh selectivity for Nile perch, Lates niloticus (L.), in the Kenyan waters of Lake Victoria, suitable mesh sizes for gillnet fleets for use in the Lake Victoria Fisheries Research Project were determined. The modal selection length for Nile perch in the mesh sized used in the earlier experiment were determined, as was the size range vulnerable to capture. Initial trials suggest 60% of the Nile perch swim within 5 m of the bottom. Setting and hauling of the nets is simple and quick, allowing the nets to be used at the same time as other sampling programmes.

Methodology of the Lake Victoria Fisheries Research Project's Co-management survey

In this book section, the theoretical background to the methodology is outlined, questionnaire development described, sample selection outlined and biases and shortcomings to the survey noted.

Ecological study of chalk streams. Lambourn project. Interim report October 1977 to April 1979

Few detailed studies have been made on the ecology of the chalk streams. A complex community of plants and animals is present and much more information is required to achieve an understanding of the requirements and interactions of all the species. It is important that the rivers affected by this scheme should be studied and kept under continued observation so that any effects produced by the scheme can be detected. The report gives a synopsis of work carried out between 1971 and 1979 focusing on the present phase 1978-1979. It assumes some familiarity with the investigations carried out on the River Lambourn during the preceding years. The aims of the present phase of the project may be divided into two broad aspects. The first involves collecting further information in the field and includes three objectives: a continuation of studies on the Lambourn sites at Bagnor; comparative studies on other chalk streams; and a comparative study on a limestone stream. The second involves detailed analyses of data previously collected to document the recovery of the Lambourn from operational pumping and to attempt to develop simple conceptual and predictive models applicable over a wide range of physical and geographical variables. (PDF contains 43 pages)

Design of a timber Howe truss highway bridge

The span of the bridge was assumed as 100 feet. The type of bridge used is the timber Howe Truss. The height of truss was taken as 20 feet between center lines of top and bottom chords. The width was taken as 18 feet center to center of trusses. The truss was divided up into five panels 20 feet long.

It was designed according to the "General Specifications for Steel Highway Bridges" by Ketchum. For the live load for the floor and its supports, a load of 80 pounds per square foot of total floor surface or a 15 ton traction engine with axles 10 feet centers and 6 feet gage, two thirds of load to be carried by rear axles.

For the truss a load of 75 pounds per square foot of floor surface.

For the wind load the bottom lateral bracing is to be designed to resist a lateral wind load of 300 pounds per foot of span; 150 pounds of this to be treated as a moving load.

The top lateral bracing is to be designed to resist a lateral wind force of 150 pounds per foot of span.

The timber to be used in the bridge is to be Douglas fir.

The unit stresses used for timber are those of the American Railway Engineering Association.

Progress report on fish counting on the Rivers Itchen and Test

This progress report summarises work on NSHEB Mark 10 fish counters which are installed at Woodmill on the River Itchen and Nurseling Mill and Connegar Bridge on the River Test. Counters are evaluated and salmon behaviour regarding the counters examined. The report includes a a list of equipment needed for the efficient running of the project in the future.