Length-weight relationships and relative conditions of two sciaenids Otolithes cuvieri Trewavas and Johnius elongatus Mohan from the Karachi coast

Estimates of length-weight relationship in Otolithes cuvieri justify separate equations for males (log W =-5.0100+3.1365 log L) and females (log W =-5.2000+3.1006 log L). Relative condition factor "Kn" was found to be 0.877-1.946 in males and 0.879-1.328 in females. High "Kn" values during March to September at 180-220 mm TL in either sexes are indicative of the maturation of gonads. Separate equations for length-weight relationship are also justified for males (log W = -5.1126 + 3.0690 log L) and females (log W = -5.6400 + 3.3070 log L) of Johnius elongatus . "Kn" values were found to be 0.924-1.894 for males and 0.894-1.087 for females. High "Kn" values during January-May and August-September at 130 mm TL onward are indicative of gonadal maturation.

The marked reduction of the Indus river flow downstream from the Kotry barrage: can the mangrove ecosystems of Pakistan survive in the resulting hypersaline environment?

This report deals with the application of knowledge of mangrove ecosystems from around the world to the understanding of the present status of mangroves ecosystems in Pakistan.

Nature of the rain spectrum at a low latitude coastal station

The internal structure of rain falls in terms of rain rate during various instances of time can be determined by measuring rain amounts received during very short intervals of time. A system that can record the intensity of rain fall at every minute has been used for this study.

Preliminary studies on the effect of irradiation as a means of preservation of fish and shellfish

Preliminary investigations on the effect of irradiation on commercially important fish and shell fish like silver pomfret, Bombay duck and prawns were conducted. Irradiated samples had an extended storage life compared to their respective controls even though yellowish or brownish discoloration occurred earlier in irradiated fish. Irradiation enhanced the rate of drip formation. Brine treatment prior to irradiation retarded this rate. Pre-blanching was found to further extend the storage life of irradiated fish.

Energetics of resting metabolism in an Indian major carp (Catla catla Ham.)

Resting metabolism in Indian major carp, Catla catla Ham. fingerlings were investigated. For this purpose a water recirculatory system in the laboratory was used. The metabolic energy losses were determined by the indirect method of oxygen consumption by the fish and were then multiplied by an oxycalorific coefficient (Q-ox). Five metabolism chambers in the experimental system were used where there were two same treatment runs in quadruplicate of mean total weight of fish fingerlings of 109.5, 110.4, 112.8 and 111.6g/chamber. The water temperature in the system was 28±0.5°C. The mean metabolic rate in the replicates showed no significant variation (p>0.05) and was found to be 151.66, 153.91, 150.25, 152.74 mgO-2/kg/h respectively. This showed an equivalent energy loss 5.40, 5.52, 5.51 and 5.56 KJ/chamber/day (35.60, 35.92, 36.67 and 36.40 KJ/kg/day) respectively. Energetics of resting metabolism in an Indian major carp (Catla catla Ham.)

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.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the University of Ceylon Vidyalankara Campus, Kelaniya (Sri Lanka). Pt. 16. the Ceylonese Trichoptera

The Trichoptera collected in Sri Lanka by the Austrian Indo-Pacific expedition in autumn and winter 1970 (larvae and adults) are evaluated systematically and ecologically. The following new species are described: Pseudoneureclipsis starmuehlneri, P. maliboda (Polycentropodidae), Oecetis belihuloya (Leptoceridae), and Helcopsyche sri lanka (Helicopsychidae). Helicopsyche ceylanica Brauer 1866 is re-described. Several types of larvae and cases of Hydropsyche (Hydropsychidae), Ceylanopsyche (Sericostomatidae) and Helicopsyche are described or at least roughly characterised. According to the larval characters the genus Ceylanopsyche seems to belong to Sericostomatidae s. str.

Avaliaçāo preliminar dos recursos de camarāo de profundidade em Moçambique

Although it is known enough of the biology of shallow+ waters shrimps, knowledge of the deep-waters shrimp is still limited. This is due to the fact that: these resources are relatively new and the study of deep waters species is more difficult and expensive. Some biological informations on the main species of shrimp in depth of Mozambique have been collected during investigation cruises (Sports et al., Pacule, 1987) and through sampling carried out on board commercial vessels (DDR fleet) between 1983 and 1986.

National Agricultural Research Organisation. Fisheries Resources Research Institute Annual Report 2001-2002

Fisheries continue to be important in the national economy, especially as an export commodity. Fish exports increased from 15,876 tonnes valued at 34.4 million US$ in 2000 to 28,153 tonnes valued at 79.0 million US$ in 2001. Consequently information for sustainable exploitation and management of fish stocks is a priority. In order to fulfill this requirement, FIRRI has been implementing two research projects. The first project focuses on sustaining and increasing capture fisheries production through management of fish stocks, biodiversity and environment of aquatic systems. The second project focuses on increasing fish production through improved fry production and pond management and feeding of cultured species.

Feeding stimulatory effects of Cyperus rotundus tuber on Cirrhinus mrigala

Traditionally tubers of cyperus (Cyperus rotundus) and its extracts have been used for alluring fish during harvesting in India. An experiment was conducted to evaluate its feeding stimulatory activity and effect on the growth of a commercially important freshwater fish, Cirrhinus mrigala. Three isonitrogenous and isocaloric formulated diets viz. plant ingredient based control and control supplemented with cyperus tuber (CS) at 1% and 5% levels were fed to the fingerlings of mrigal, C. mrigala (2.68+0.20 g) for a period of 45 days. The growth performance and the activity of metabolic enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), in liver, gill and muscle tissues of mrigal were studied during every 15 days interval. Highest relative growth (72.28%) was obtained in the mrigal fed with the diet containing 5% cyperus (5% CS), while the relative growths were 66.18% and 43.40% for the fish fed with the 1% CS diet and control respectively. The activities of AST and ALT were significantly higher (p<0.01) in both 1% and 5% CS diets as compared to the control in all the tissues studied. Higher aminotransferase activities were observed in the tissues of 5% CS group than in those of 1% CS group throughout the experimental period. The observed higher enzymatic activity was concomitant with the higher growth rate in fish. The results suggested that cyperus tuber supplementation increased feed palatability and growth.

A study on performances of intensification in the farming system of a shrimp farm at Cox's Bazar, Bangladesh

This study examines the harvest and mean production in relation to the stocking of P. monodon fry during the period between March 1992 and October 1994, at the farm owned by M/s Monugung Sea Food Ltd., Cox's Bazar. The analysis shows that production figures were initially up to expectation, but after harvesting 4 crops within 16 months, production sharply decreased. The unexpected high mortality of the growing stock was due to outbreak of an uncontrollabe disease (Vibriosis). Significantly higher variations in production, survival and growth were also noted among the different treatments.

Over-wintering performance of mixed sex and monosex tilapia (Oreochromis niloticus L.) in Bangladesh

An experiment was conducted for six months in 6 experimental ponds (each size 80 of m2) to assess the over-wintering performance between mixed sex and monosex tilapia, Oreochromis niloticus. The experiment was carried out with two treatments each with three replicates. In the first treatment (T1), mixed sex tilapia were stocked in 3 ponds with a mean initial of 4.80±0.18 g. In the second treatment (T2), monosex tilapia were stocked in another 3 ponds with a mean initial weight of 4.81 ±0.20 g. Each pond was stocked with 250 fingerlings. Fish were fed at the rate of 6% of fish body weight at the beginning. The feeding rate was gradually reduced to 2% for the third month and finally increased to 3% for rest of the period. Water quality was monitored fortnightly and the ranges were: temperature17.86-29.10°C, dissolved oxygen 4.25-6.10 mg/1, pH 6.97-7.20 and transparency 24.10-36.50 cm. After 6 months of rearing monosex tilapia attained a significantly (p

Some aspects of the biology of Johnieops sina (Cuvier, 1830) from Mumbai waters

Investigations on food and feeding of Johnieops sina indicated that it feeds mainly on penaeid prawns, Acetes spp. and fishes. Penaeid prawns were found to be its preferred food item. The spawning activity was observed throughout the year with two peaks in February and August, supported by prominent peaks of gonadosomatic index in the same months. The minimum size at first maturity for females was 153 mm. The absolute fecundity ranged from 28,495 to 135,346 eggs for the ovaries weighing 1.30 to 9.49 g.

Experimental formulation of an anti fouling paint with tributyl tin oxide as toxic pigment

Results of the experimental formulation of an antifouling paint incorporating TBTO as toxic pigment are presented in this paper. Of the various resins tested, namely, phenolic, cashew nut shell liquid (CNSL), epoxy linseed oil with rosin and limed rosin, the paint composition with limed rosin gave the critical leaching rate of TBTO. Acid alkali test showed dissolution of matrix and visible migration of toxin to the surface. Accelerated corrosion tests had not recorded any signs of corrosion in panels painted with or without barrier coat. Raft exposure studies indicated that the new formulation could resist fouling accumulation on painted panels for 9 months.

Proximate composition of 17 species of Indian fish

Miscellaneous fish from the catches of shrimp trawlers constitute a major portion of the marine fish catch in India, its quantity in annual landing being of the order of 50,000 tons. At present it is often not brought to the shore since it fetches only very low price. It consists of several species and is a cheap source of animal protein. Attempts are made in India in various centres (Anon. 1972-73) to utilise them effectively by formulating various speciality products acceptable to consumers.