Offshore geology of Pakistan and non-living resource prospects

Offshore geology of Pakistan is characterized by active and passive continental margins. These continental margins show very unique features such as an active Makran subduction zone in the west and the Indus delta and a submarine fan in the east. The geology of these features of Pakistan EEZ is inadequately known. This is a major obstacle in exploring mineral resources. Detailed study of coastal and shelf geology is needed for better understanding of the geology of the area and comprehensive evolution of its non-living resource potential. An understanding of the geological events including tectonic movements, sedimentation processes and geochemical history that comprise the geological history is very important to help in identification and estimation of resources. In Pakistan EEZ applying the current technology and undertaking research work to understand the seafloor features and mineral deposits associated with it will be very fruitful

Status of the demersal fishery resources of Bangladesh

The present study makes use of the fisheries survey data collected during the period 1984 - 87 by the multi-purpose research vessel RV Anusandhani in the waters of Bangladesh, Bay of Bengal. The data consists of twelve survey cruises directed at the shrimp resources (1985 - 87) and nineteen survey cruises directed at the demersal fish resources (1984 - 86). The biomasses for shrimp and demersal fish during the survey period were estimated, along with a detailed analysis of biomass distribution by depth zone and catch rates for important species of shrimp and demersal fish species. The demersal fish and shrimp biomass during the survey period was estimated as 176 160 t and 857 t, respectively. The levels of biomass when compared with 1973 estimates indicate a tremendous decline, by about 90% for shrimps and 30% for demersal fish. Population parameters for four species of shrimps (for both males and females) as well as for eight demersal fish species were also estimated. The parameter estimates were validated using available growth and mortality parameter values from the literature, and were in turn used to estimate the mean exploitation rate (E) of demersal fish and shrimp species comprising the trawl catch. Mean E values for shrimp species is at 0.61 and 0.57 for demersal fish species, indicating over-exploitation of demersal resources in the Bay of Bengal. Exploratory analysis using surplus production modeling of catch and effort data shows that the maximum sustainable yield (MSY) level for shrimp resources is around 3 500 t, corresponding to a maximum effort level of approximately 6 480 fishing days. Similar analysis for demersal fish catches gave poor correlations between catch rates and fishing effort.Fishery resources, Demersal fisherie, Fishery surveys, Biomass, Population density, Shrimp fisheries, Catch/effort, ISW, Bangladesh,

Arabian Sea sub-surface salinity minima (ASSM)

This paper presents the results of the study on the Arabian Sea sub-surface salinity minima (ASSM). The data collected under the North Arabian Sea Environment and Ecosystem Research (NASEER) programme and World Ocean Circulation Experiment (WOCE) has been used in the study. Study of the Arabian Sea water masses is most significant in understanding marine productivity and monsoonal reversal features. Analysis of the data shows that the Arabian Sea sub-surface salinity minima (ASSM) can be found between 25.8 to 26.0 Sigma Theta surfaces. ASSM originates from the south and south east. It is inferred from the results that the salt content of the ASSM varies during different seasons. Appreciable mixing of Arabian Sea salinity minima is observed over Murray Ridge

The existence of contingent epiderivatives for set-valued maps

AbstractThis short note deals with the issue of existence of contingent epiderivatives for set-valued maps defined from a real normed space to the real line. A theorem of Jahn-Rauh [1], given for the existence of contingent epiderivatives, is used to obtain more general existence results. The strength and the limitations of the main result are discussed by means of some examples

Comparative efficiency of frame nets and trammel nets

Fishing experiments were conducted simultaneously with frame nets and trammel nets in the Hirakud Reservoir and the results indicated the relative superiority of frame nets, whose catch rate was two times more than that of the trammel nets

Eradication of uneconomical fishes with simple gill nets at Hirakud reservoir

Experiments with simple gill nets of mesh bar 25, 30, 35, 40 and 45 mm were carried out to determine the suitable mesh size for the eradication of the uneconomical fishes of Hirakud reservoir. Results show that net with 25 mm bar is more suitable particularly for Gudusia chapra (Ham), Rohtee cotio (Day) and Eutropichthys vacha (Ham)

Effect of hanging coefficient on the efficiency of frame net

Comparative fishing experiments with frame nets of 0.4 and 0.5 hanging coefficients were conducted. Results indicate that net with hanging coefficient of 0.4 as more effective for better catch

On the fishing power of monofilament and multifilament gill nets

The authors have discussed the results of comparative fishing, conducted in the Govindsagar reservoir, with simple monofilament and multifilament gill nets. The experiments were conducted both in clear and turbid water. In both these water masses, the monofilament gill net has been found to be more efficient. It is also found that the four major species of fishes of the reservoir have not shown any preference towards a specific gear

Coloured gill nets for reservoir fishing

Experimental fishing with different coloured nets has shown that white net yields better catch. The efficiency of the coloured nets was in the order yellow, grey, green and blue. Though there is little evidence to show some species preference to a particular colour, the results were not conclusive as the analysis of variance indicated that interaction between species and colour is significant only at 5% level