Rearing of prawn larvae for seed production

Rearing the newly hatched prawn larvae is the most demanding of the procedures in hatchery production of seeds. Freshly spawned eggs of the penaeid prawn hatch out into nauplii which pass through protozoea and mysis stages before metamorphosing into post larvae

Prawn hatchery at Mopla bay with CMFRI technology

The work included selecting the site, designing the hatchery, supervising and monitoring its construction, demonstration of seed production and training the staff from the MATSYAFED. The hatchery is designed to produce 10 lakhs of post larvae XV - XX for every hatchery run. The daily schedule of management of the larval rearing tanks, the phytoplankton culture tanks and the observations to be made to assure the quality of larvae, their activities and well being were informed to the staff undergoing training

A possible observational bias in the estimation of the virial parameter in virialized clumps

The dynamics of massive clumps, the environment where massive stars originate, is still unclear. Many theories predict that these regions are in a state of near-virial equilibrium, or near energy equi-partition, while others predict that clumps are in a sub-virial state. Observationally, the majority of the massive clumps are in a sub-virial state with a clear anti-correlation between the virial parameter $\alpha_{vir}$ and the mass of the clumps $M_{c}$, which suggests that the more massive objects are also the more gravitationally bound. Although this trend is observed at all scales, from massive clouds down to star-forming cores, theories do not predict it. In this work we show how, starting from virialized clumps, an observational bias is introduced in the specific case where the kinetic and the gravitational energies are estimated in different volumes within clumps and how it can contribute to the spurious $\alpha_{vir}-M_{c}$ anti-correlation in these data. As a result, the observed effective virial parameter $\tilde{\alpha}_{eff}<\alpha_{vir}$, and in some circumstances it might not be representative of the virial state of the observed clumps.Comment: A&A letter, accepte

Some trends observed in the deep-sea lobster catches of the vessel "Blue Fin" during the period January '69 to December '71

During the past two decades there have been sporadic attempts to explore the lobster resources especially the deep-sea lobster along the Kerala coast. Even as early as 1901 (Alcock, A) the occurrence of deep-sea lobster off the Travancore coast has been recorded

Mixed farming or polyculture

In Kerala, nearly 75-80% of the population consume fish and their annual per capita consumption rate is about 13 kg. The rate of fish consumption is likely to go up due to increased awareness about fish as a source of cheap and highly nutritious but harmless food item. Hence there is every need to augment fish production not only to meet our food requirements but also to increase foreign exchange earnings. The current level of fish production is inadequate to fulfil all these needs. An analysis of the trend of fish production during the past few years indicates that there may not be any significant improvement in it in the coming years. In this context, measures to increase fish production are to be thought of Aquaculture is the only way to achieve this. In Kerala at present aquaculture is restricted to backwaters and inland waterbodies. In order to enhance fish production, farming of fish and other species of aquatic organisms is to be extended to inshore coastal waters for which suitable farming methods are to be adopted

Description of the male of Caligus hilase Shaw (Copepoda, Caligidae)

Caligus hil.rae Shen, 1957, is unique in the possession of a comparatively very long four-segmented abdomen, long anal laminae which are nearly three times as long as broad and in the absence of the sternal fork

Marine Biodiversity: Conservation and management-Introduction

There has been a realisation in the latter part of twentieth century on the imperative need to protect and conserve the habitats and their resources. In the Biodiversity convention at the UN Conference on Environment and Development (UNCED) the term biodiversity is defined as "the variability among living organisms from all sources including inter alia, terrestial, marine and other ecosystems and the ecological complexes of which they are part, this includes diversity within species, between species and of ecosystems.

സമ്മിശ്ര മത്സ്യകൃഷി (Mixed farming or Polyculture)

The rate of fish consumption is likely to go up due to increased awareness about fish as a source of cheap and highly nutritious but harmless food item. Hence there is every need to augment fish production not only to meet our food requirements but also to increase foreign exchange earnings. The current level of fish production is inadequate to fulfil all these needs. An analysis of the trend of fish production during the past few years indicates that there may not be any significant improvement in it in the coming years. In this context, measures to increase fish production are to be thought of Aquaculture is the only way to achieve this. In Kerala at present aquaculture is restricted to backwaters and inland waterbodies. In order to enhance fish production, farming of fish and other species of aquatic organisms is to be extended to inshore coastal waters for which suitable farming methods are to be adopted

The Failure of Teton Dam – A New Theory Based on State Based Soil Mechanics

Teton Dam failed during its first filling on 5 June 1976. The 405-ft high dam was designed and built using modern standards; therefore its failure received considerable scrutiny from engineering experts. Failure mechanisms suggested, included hydraulic fracture, internal erosion, wet-seam theory, and defects in the abutment rock. None of the investigations, however, were able to explain satisfactorily why the dam breached when the reservoir reached EL.5301.7 ft and only in the vicinity of Sta. 14+00 on the right abutment. The investigation here is focused on this crucial aspect of the failure using the modern framework of fundamental “state based soil mechanics”. According to this framework highly compacted soils of low plasticity in an environment of low liquidity index and low confining stress would crack in the presence of high shear stresses. The impervious core (Zone-1) of Teton was constructed of uniform clayey silt of low plasticity and highly compacted and therefore was prone to such a possibility. This paper describes the details of the theory, the investigation, and the conclusions arrived at regarding the potential initiation of Teton failure. Finite element analysis carried out using state based parameters indicate the presence of deep open transverse vertical crack(s) in the core (Zone-1) to a maximum depth of about 32 ft from the crest only in the right abutment and in the vicinity of Sta. 14+00. We conclude that once the water level in the reservoir rose above El 5300.0 ft in the early hours of 5 June 1976 water flowed through the open vertical crack(s), which slowly eroded the crack into a large tunnel leading to the major breach of the dam hours later