Methods and tools for the assessment of daylight transmittance through expanded metal meshes

306 p.

An assessment of the efficiency of three active fish capture methods and a study of roach / bream hybrids on the Crossens drainage system near Southport.

An assessment of three methods of fish capture, to establish the best fishing method which reflects the best range of sizes and species of fish in a given area. The methods used were trawl netting, electrofishing, and seine netting which were assessed on the Crossens drainage system near Southport. The report also includes a study of roach / bream hybrids that were found at the site, which focuses on their distinguishing features and compared with the features of roach and bream.

Improving methods and indicators for evaluating coastal water eutrophication: a pilot study in the Gulf of Maine

Study Goals and Objectives: 1) Improve existing nutrient-related eutrophication assessment methods, updating (from early 1990s to early 2000s) the eutrophication assessment for systems included in the study with the improved method. 2) Develop a human-use/socioeconomic indicator to complement the assessment indicator. The human-use indicator was developed to evaluate costs of nutrient-related degradation in coastal waters and to put the issue into a broader context relevant to the interested public and legislators as well as to scientists. 3) Project objectives included collecting existing water quality data, developing an accessible database appropriate for application to a national study, and applying the assessment methods to 14 coastal systems – nine systems north of Cape Cod and five systems south. The geographical distribution of systems was used to examine potential regional differences in condition. 4) The intent is to use the lessons learned in this pilot study on a national scale to guide completion of an update of the 1999 National Estuarine Eutrophication Assessment.

Feasibility study: the methods and approaches to implementing a SEREAD teacher training programme in BOBLME countries

Objectives included a desk-top feasibility study to explore opportunities to adapt the Scientific Educational Resources and Experience Associated with the Deployment of Argo profiling floats in the South Pacific Ocean (SEREAD) to BOBLME country schools.The programme included teacher resources on climate change and facilitating interactions between scientists, students and teachers.

Impacts of fishing gears, fishing methods and fishing effort in the fisheries of Lake Victoria and proposals for management

The initial subsistence fisheries of Lake Victoria were dominated by two indigenous tilapiines, Oreochromis esculentus (Graham 1929) and Oreochromis variabilis Boulenger 1906, exploited with simple fishing crafts and gears that had little impact on the fish stocks (Jackson 1971). Commercial fisheries, targeting the tilapia fishery, started at the beginning of the 20th Centurywhen cotton flax gillnets were first introduced in 1905 into the Nyanza Gulf in Kenya. Gillnets were quickly adopted around the whole lake and consequently, the native methods of fishing soon died out (Jackson 1971). Following the introduction of gillnets, fishing boats and their propulsion methods were also improved. These improvements in fishing capacity coincided with development of urban centres and increasing human population around the lake, which increased the demand for fishery products. To satisfy the increasing demand, fishing effort increased greatly during the 20th century, despite the decline of catch per unit of effort (CPUE) (Jackson 1971; Ogutu-Ohwayo 1990). The initial catch rates of 127mm (5 inch) mesh size gill nets in the tilapia-based fishery, in 1905, was in the range of 50 to 100 fish per gillnet of approximately 50 m in length. However, twenty years later, the catch rates of gillnets of the same mesh size had declined to about six fish per net and gillnets of smaller mesh sizes, which had better catch rates, had been introduced suggesting overfishing (Worthington and Worthington, 1933).

Fishery methods and fish diversity in the Kilombero River in south-eastern Tanzania

Assessment of common fishery methods and of fish diversity was undertaken in two fishing camps on the Kilombero River in south-eastern Tanzania in surveys towards the end of the dry season, 1994. Fishermen identified 23 different types of fish that they caught on a regular basis. Only 19 species of fish, belonging to 17 genera and 11 families were, however, identified according to Linnean taxonomy. Hooks, nets, traps and spears were used to catch fish. Fish were either sold fresh. or preserved for storage and long-distance tranport by smoking or frying. based un frequency distributions of the numbers of fish landed over a 4 day period at one of the camps, a Shannon-diversity index of 1.95 was calculted. The fork (or total) length of 480 fish and the weight of 413 fish were measured and length frequency distributions as well as length-weight relationships determined for the six most common species. It is concluded that local fishing methods applied in the Kilombero River allow for sustainable fish production.