Studies on the fishery of the penaeid prawn Metapenaeus affinis (Milne Edwards) Along the Mangalore coast

Tbe fishery anl certain features of the population structures of M. affiMs caught by the trawlers fran 1962 through 1971 are reported. The fishery was chiefly i^odal and was dominated by large size groups early in the season and smaller size groups later. The maximum number of broods entering the fishery was observed to be four. Age and growth studies indicated that tbe males attain a length of about 95, 140 and 160 mm and females, lOO, 143 and 170 mm at the end of one, two and three years, respectively. The miniminn size at first maturity for males was found tp be 116 mm. The average annual instantaneous fishing mwtality was found to be 3.76 for males and 2.50 for females between one and two year olds

Prawn fishery of Alleppey coast during the S.W. monsoons of 1972-1976

The annual total catch of prawns showed wide fluctuations. The catch per unit effort varied considerably from month to month of the same season and also duting the corresponding months of different seasons. The prawn catch was mainly constituted by Metapenaeus dobsoni (Miers). June-July months were more productive on account of recruitment of more individuals belonging to higher size groups. The monthly average mean sizes of M. dobsoni showed great disparity, ranging between 75.2 mm and 91.5 mm for males and 81.3 mm and 103.4 mm for females. In the species, males were found in a higher proportion than females in lower size groups, but females occurred in higher proportions in higher size groups. The recruitment of mature females into the fishery was quite irregular throughout the seasons of different years under study. The analysis of stomac

On the prawn fishery by trawlers off Purakad, Sw coast, during 1972-76

The total catches indicated that the prawn fishery off Purakad was on a steadily declining trend from 1972, except for 1974, the total catch of over 2000 t in 1972 declining to less than 200 t in 1976. Though quantitatively all the species were heavily suffering the decline, with the relative proportion more steeply declining, from 29% in 72 to 6% in 76, P. indicus seems to be the species that was most affected; and M. dobsoni, increasing from 52% in 72 to 72% in 76, the least

Tidal waves cause damages to coastal villages in Kerala

The article reports on the damages caused by giant tidal waves to coastal villages between Aarattupuzha (Alleppey District) in the south and Nattika (Trichur District) in the north for a distance of about 150 km along the Kerala coast. The giant tidal waves struck hard against the shore and rolled over into the low lying areas filling the sea water in the huts, wells, paddy fields etc. The damages were the minimum where ever the sea walls were present. But such calamities are unpredictable, hence the practical solution to such sudden natural calamities is to protect the coast line by constructing sea wall wherever the same is not present

Population characteristics and exploitation of the important marine prawns of Ambalapuzha, Kerala

The monthly landings of the different species and the effort expended show wide fluctuations. However, the catch per unit of effort and the mean size of the different speci(« do not show a regular declining trend. It has been found that the successful spawning by the surviving spawners and the subsequent recruitment of younger prawns into the fishable stock greatly influence the fluctuations in the landings. Ecological changes brought out by the physico-chemical distorbaiKes in the envirmunent and their influence on prawn landings are dbcossed

Zooplankton abundance in the continental shelf waters of the northeast coast of India

Higher concentrations of zooplankton standing stock and population occurred in the region off Chilka lake and Paradip (19° 10'N-19° 55'N and 85°09'E-86° 50'E) during January and off Visakhapatnam (17°30'N- 18°28'N and 83°14'E- 84°29*E) during November and April. The most productive period along the northwestern part of the Bay of Bengal was the northeast monsoon season (October-January) followed by the premonsoon season (February-May). High abundance of copepods, chaetognaths, siphonophores, cladocerans, fish larvae, planktonic molluscs, amphipods, foraminifers and larval polychaetes constituted the northeast monsoon maximum. Very low biomass values were recorded during the southwest monsoon season (June-September). The neretic zone up to 50 m depth was rich in zooplankton population during northeast monsoon and further to a lesser extent up to 100 m during the premonsoon season. However, a steady decline was evident with increasing depth zones. The less saline northern part exhibited remarkable differences in the abundance of the population and standing stock in such a way that 63% of the total was confined to the northern region. Fish eggs were predominant during February-May and larvae in July and January-February. The peak period of the zooplankton population coincided with the maximum landings of the pelagic and demersal fishery resources of the northwestern coast of the Bay of Bengal

Resource assessment of the penaeid prawn Metapenaeus dobsoni (Miers) along the Mangalore coast

The fishery and certain aspects of the population characteristics of M. dobxoni from 1962 through 1971 are reported. The fishery was generally bimodal with peaks during March-April and September-October and showed wide annual fluctuations. Th-; total catch showed a gradually diminishing increase when the fishing effort reached a level of about 14,000 boat days. The catch per boat day also showed a downward trend, in general. It would appear, therefore that any additional increase in 'effort would be of little consequence in raising the yield. The fishery was dominated by larger size groups (above 95 mm) during JiilyiNovember. Recruitment of smaller size groups (60 mm onwards) was observed duping DeC'imber-January. The maximum number of broods entering the fishery was five. Age and growth studies indicated that the males and females attain a length of 85 and 105 mm and 95 and 120 mm at the end of one and two years respectively. Th-ereafter very little growth seems to take place. The late 'O' and the one year class formed the mainstay of the fishery. The mean length showed considerable annual fluctuations but these changes appear to be only due to natural causes. Females preponderated in all the years except during 1965-66. They often tended to exceed the males by more than 1.5 times during .April-May and November- December which more or less coincided with periods of intense breeding activity. The average annual instantaneous rate of mortality between one and two year olds was found to be 4.18 and 4.61 for males and females respectively. The fluctuations in the annual rainfall seem to bear a direct relation to the magnitude of the fishery. No clear-cut relationship between the juvenile abundance in the estuary and the marine fishery was discernible

Laboratory phenomics predicts field performance and identifies superior indica haplotypes for early seedling vigour in dry direct-seeded rice

Seedling vigour is an important agronomic trait and is gaining attention in Asian rice (Oryza sativa) as cultivation practices shift from transplanting to forms of direct seeding. To understand the genetic control of rice seedling vigour in dry direct seeded (aerobic) conditions we measured multiple seedling traits in 684 accessions from the 3000 Rice Genomes (3K-RG) population in both the laboratory and field at three planting depths. Our data show that phenotyping of mesocotyl length in laboratory conditions is a good predictor of field performance. By performing a genome wide association study, we found that the main QTL for mesocotyl length, percentage seedling emergence and shoot biomass are co-located on the short arm of chromosome 7. We show that haplotypes in the indica subgroup from this region can be used to predict the seedling vigour of 3K-RG accessions. The selected accessions may serve as potential donors in genomics-assisted breeding programs

Studies on Composite Extrudable Propellant with varied Burning Rate Pressure Index 'n'

This paper discusses the development of composite propellantextrusion technique and the study of burning rate pressure indices nwith respect to compositional variations. The n is found to vary from0.35 to plateau and plateau to mesa by suitable compositionalmodifications. Compositional influence on burning rate with specificreference to plateau and mesaburning additives is described. Detailsof the process parameters like fluidity of the slurry, extrusion pressure,extrusion rate and die-swell are presented. This propellant is based onISRO-CTPB binder using ISRO-AP as oxidizer. Ammonium perchlorate (AP) particle size variation and inclusion of additives likePVC, lead stearate, ammonium sulphate, lithium fluoride etc. are foundto influence the burning rate pressure index n