The design and construction of flat rectangular otter boards for bottom trawling: a review

The design and construction of the otter board is a subject of great importance for economy in trawling. This review incorporates a historical resume tracing the change and development• of otter boards. The size of the otter board and its relationship with the horse power of the engine and size of the net and the methods of rigging are dealt with. The factors influencing the horizontal spread are discussed. The effect of the angles of attack, heel and tilt and the ground reaction on the force coefficients have been reviewed and discussed with particular reference to flat rectangular otter boards used for bottom trawling. A short account of other designs of otter boards used for improved efficiency is given. Suggestion for improving the efficacy of otter boards based on the work hitherto done has been made. The contributions relating to the various aspects of design and performance of trawl boards carried out till 1969 have been considered.

Institutional, policy and regulatory framework for sustainable development of the Egyptian aquaculture sector

This report presents the findings of a mission to critically review the institutional, policy and regulatory framework for sustainable development of the Egyptian aquaculture sector. The study was undertaken by an International Expert on Aquaculture Policy, and a National Expert on Institutions, on behalf of the Project “Improving Employment and Income through the Development of Egypt’s Aquaculture Sector“, implemented by WorldFish and CARE, and funded by the Swiss Agency for Development and Cooperation(SDC). The objective of the mission was to assess the current status of the Egyptian aquaculture sector, in terms of the policy, legal and institutional environment, with a view to suggesting the major issues to be addressed within a future policy dialogue.

A preliminary account and review of the simple methods for determining the operational parameters of fishing gear, underwater, with notes on its application

An account and review of the simple methods for determining the operational parameters of fishing gear, underwater, such a tilt of otter boards (outwards or inwards, forwards or afterwards), vertical height of net, its horizontal spread, angle of divergence at bosom, spread between wing tips, angle of inclination of danlenos, butterfly, slope of legs and sweep-line has been given. The relationship of distance between the otter boards spread and the vertical height of net has been obtained as generally linear. The possibilities of regulating the vertical height of net (dependent variate) and spread of otter boards (independent variate) for increasing the fishing efficiency has been discussed. The angle of attack of oval shaped otter boards used during the operations still remain undetermined, however, it has been explained how the best angle of attack for increasing the efficiency of gear can be obtained by regulating the ratio of depth to warp for a given net. The inadequacy of the mere indices of catch per hour of trawling in comparing the relative efficiency of trawls in gear research studies has been indicated. The importance of estimating the operational parameters and its application to commercial fisheries depending upon the distribution pattern of fish and in gear research has been discussed. The efficiency of the jelly bottle method has been compared statistically with the observations made on the trawl gear underwater with instruments.

A review of experimental trawling from small and medium sized mechanized vessels off Kanikada

The most suitable otter trawl for small boats was found to be a 10.9 to 15m 2-seam trawl with 100cm x 50cm x 35kg horizontally curved otter boards together with long single sweep line. For operation from medium sized trawls, 18.26m 2-seam 18.3m 4-seam and 29.26m long wing trawl were found suitable. An 18.3m 4-seam trawl was netting a considerable quantity of off-bottom fishes. Shrimps predominated in the catches of the 29.26m trawl. Productive grounds for Cynagris species, Psenus species and Decapterus species within 50 to 100m depth ranges off Kakinada were available for profitable exploitation.