On continued culture trials of Lates calcarifer (Bloch) and Oreochromis mossambicus in the ponds of Kharland Research Station, Panvel, Maharashtra

Pond culture trials of Lates calcarifer (Bloch) were initiated in the ponds of Kharland Research Station, Panvel, from 1985 up to 1989 by adopting varying methods of inputs of commonly available organic substances comprising de-oiled cake of groundnut, rice bran and raw cattle dung. Although provision of zooplankton generated under phased fertilisation technique resulted in considerable yield level, subsequent trials in combination with direct feed methods gave higher yield. Trials during 1990-91 adopting similar feed input techniques were continued but by stocking the seed of both Lates and Oreochromis mossambicus with yield percentage around 72.23 for Lates and 27.73 for Oreochromis. Trials were further continued during next three years. In relation to the organic input levels the yields rate for seven months period was in the range of 119.4 kg/ha to 250.4 kg/ha for Lates. In case of Oreochromis the yield rate varied between 28.5 to 153.32 kg/ha indicating the influence of differential stocking rates and size of the seed of two species.

Investigations on long distance transportation of fish. 3. Field trials with a dismantlable insulated galvanised iron container

The paper communicates the results of field trials conducted with a dismantlable insulated galvanised iron container designed and fabricated by the first two authors in their laboratory. Different varieties of fishes and different types of packing, namely, fresh iced, chilled iced and frozen were employed in the transportation experiments which were conducted from Kakinada to Howrah, Kakinada to New Delhi and Paradeep to Howrah. In all the experiments the container performed exceedingly well and has still remained in very trim condition.

Investigations on the number of trials required for statistical comparison of fishing gears

The number of fishing trials required for comparing the efficiency of fishing gears was investigated. A unique solution to this problem did not appear to exist because of the heterogeneity of the experimental material. Sequential experimentation and analysis have been found to be a practical approach to this problem. By this, the experiment can be terminated almost after 35 days fishing for catches with standard error per unit as per cent of the mean about 30% or less (after logarithmic transformation). For data with mean catches less than 1.5 kg analysis of variance approach does not appear to be meaningful.

Preliminary trials in Artemia rearing and salt production in earthen salt ponds

The authors report on the production of Artemia obtained on a 0.5 ha pilot project with combined trials in Artemia rearing with solar salt production during the dry seasons and with production of milkfish (Chanos chanos) fingerlings and/or prawn (Penaeid sp.) juveniles during the rainy season in the Philippines.

Commercial small craft pair trawling trials Lake Chilwa, Malawi 1971

The results are reported of commercial small craft pair trawling trials conducted on Lake Chilwa from May to August 1971. Type of vessels and equipment used and the fishing method and operation employed are described and design data given for the different trawls used. The effects on catching efficiency of varying amounts of small mesh netting trawls are dealt with and recommendations made for trawls design modifications.

Preliminary results from a bottom trawl survey of Lake Rudolf with additional notes on trials with a midwater frame trawl

This paper includes a short report on preliminary midwater hauls with a frame trawl. The object is (a) to study the relationship between the vertical distribution of pelagic fish and the scattering layer, and (b) to find out if certain species, which at times occur abundantly in the bottom-trawl on the shallow-water frontiers of the scattering layer, might extend into offshore waters to constitute an important pelagic resource.