Reviving the Macrobrachium rosenbergii (de Man) fishery in Vembanad Lake, India

In Vembanad Lake and its confluent rivers (Kerala, India), the catches of Macrobrachium rosenbergii (de Man) were reported to have dwindled to a mere 39 t in the 1980s from average landings of 300 t during the 1960s. This decline is due to the impact of a number of human interventions affecting the ecosystem and, hence, the stocks of M. rosenbergii. Monitoring of landings in 1994-1995 and 1995-1996 indicates an improvement in catches. This paper discusses the reasons for the decline and revival in stocks and suggestions for their replenishment

Secondary students beliefs about, understandings of, and intentions to act regarding the greenhouse effect

The greenhouse effect (GHE) is a concern to everyone on this planet. To understand the GHE, students and citizens need an understanding of the chemical processes underlying this environmental phenomenon. Citizens need to be scientifically literate in relation to this phenomenon in order to participate in democratic decision-making and to take appropriate actions in their daily lives. As the GHE is a global issue it will require collective and individual actions to prepare for the likely climatic changes and to reduce the further impact of the GHE. This study focused on high school students\u27 beliefs about, understandings of the GHE and their intentions to act in ways that would reduce greenhouse gas emissions. Aspects of the GHE that are taught in high school science were also investigated. The study was conducted in five schools each in Western Australia (Australia) and Kerala (India) and data were collected from 438 Year 10 and 12 students representing compulsory and post-compulsory stages of education in both states. Two hundred and thirteen students from Western Australia and 225 students from Kerala completed a questionnaire and a sample of students and heads of science were interviewed. A Propositional Knowledge Statement (PKS) was developed, which is a set of propositions that outline science concepts necessary for an understanding of the GHE in terms of its causes, effects, mechanism and actions that can be taken to reduce greenhouse gas emission. In this study the PKS is considered to be the essential knowledge necessary to interpret the GHE, to take appropriate environmental action, and to make informed decisions as a scientifically literate member of society. The questionnaire and interviews were based on the PKS. The study revealed that high school students strongly believe that the GHE is real and affecting the climate at present and will also affect it in the future. They consider that the GHE is a relatively important social issue and they believe that governments should conduct programmes to raise community awareness and enact strict laws to reduce the release of greenhouse gases. Students\u27 understanding of the GHE is inadequate to make informed decisions and take appropriate environmental actions as a scientifically literate member of society. The majority of students and their families are already taking or are considering taking 10 accepted actions to reduce greenhouse gas emissions by household activities. The majority of students are not prepared to sacrifice their personal comforts or conveniences to reduce greenhouse gas emissions and they have strong reasons for that, however, they believe that governments should enact strict laws to reduce greenhouse gas emissions and should sign the Kyoto protocol. The GHE is not adequately represented in Western Australian and Kerala science and chemistry curricula. The heads of school science departments in Western Australia and Kerala consider that school science should do more to teach the GHE, as it is an important aspect of scientific literacy. An ideal scenario for students’ beliefs about, understanding of the GHE and commitments to take action that would enable individuals and communities to reduce greenhouse gas emission was developed based on the PKS and reports such as lPCC (2001), UNEP (2001), AGO (1999; 2000) and UN (1992). The actual scenario was based on the data from this study. The differences between ideal and actual scenarios were discussed and implications for improving education about the OHE were developed. Information about the curriculum and students\u27 sources of information about the GHE, students\u27 beliefs, understandings and intentions to act were mapped against the theory of reasoned action (Ajzen & Fishbein, 1980)

Demersal fish assemblages of the Southwest Coast of India

Demersal surveys from the southwest coast of India were analyzed to determine the general pattern of distribution of demersal species assemblages in the area. Seasonality is pronounced, indicating three major periods, pre-monsoon, monsoon and post-monsoon. Each of the periods is characterized by different oceanographic circulation patterns that mainly determine the pattern of distribution of species assemblages. Spatial analysis confirmed that the Wadge Bank has the highest potential for producing good quality fish. Region-wise analysis of data indicated that maximum effort and highest landings are from the known grounds along the southwest coast, although certain northern areas were also found to be fairly productive.Fishery resources, Demersal fisheries, Fishery surveys, Biomass, Population density, Shrimp fisheries, Catch/effort, Trawling, Population characteristics, ISW, India, Southwest,

Trophic model of the coastal fisheries ecosystem of the southwest coast of India

The Ecopath approach and software were used to construct a trophic model of the coastal fisheries ecosystem of the southwest (SW) coast of India. The model consisted of 11 ecological groups and used estimated landings from all areas along the southwest coast (based on the sample surveys conducted by Coastal Marine Fisheries Research Institute for the years 1994, 1995 and 1996). The trophic model suggests high catch levels, particularly for the large and medium predators, demersal feeders and detritivores. The biomass estimates in the trophic model were comparable to the biomass estimates from trawl surveys based on the swept area method for the southwest coast.Fishery resources, Demersal fisheries, Fishery surveys, Biomass, Population density, Shrimp fisheries, Catch/effort, Trawling, Mathematical models, Coastal fisheries, ISW, India,

A preliminary assessment of the coastal fishery resources in India: socioeconomic and bioeconomic perspective

India is endowed with a continental shelf of 0.5 million km2 and an exclusive economic zone (EEZ) of about 2 million km2. Almost half (39%) of the Indian population utilizes the marine fisheries resources. India ranked sixth worldwide in total fish production (4.95 million t) and second in inland fish production (2.24 million t) during 1995 - 96. Fish production expanded from 0.75 million t in 1950 - 51 to 4.95 million t in 1995 - 96, giving a significant increase at a cumulative growth rate of 4.2% per annum. Marine fish production increased from 0.53 million t in 1950 - 51 to 2.71 million t in 1995 - 96. The contribution of the fisheries sector to the total gross domestic product (GDP) improved from 0.75% in 1980 - 81 to 1.28% in 1994 - 95, with marine fisheries providing employment opportunities both in the production and post-harvest sectors. Subsidiary employment in fishing includes boat building and repair, net mending, repair of engines and supply of diesel, kerosene and other essential items. Women are mostly engaged in post-harvest operations like net mending, fish processing, packing and selling of fish and fish products. The contribution to foreign exchange earnings by the fishery sector substantially increased from Rs46 crores in 1960 - 61 to Rs4 697 (US$121*) in 1997 - 98. India exports about 55 types of marine products to different countries in Southwest Asia, Europe and USA. The total quantity of marine product exports rose from 97 200 t in 1987 - 88 to 307 337 t in 1994 - 95 giving an equivalent export value of Rs53 000 lakhs to Rs357 500 lakhs**. The marine fishing sector can be classified into: (a) non-motorized artisanal sector using country craft with traditional gear; (b) motorized sector; (c) mechanized sector using inboard engines of 50 to 120 HP; and (d) deep sea fishing with bigger boats (25 m and above) and engines of 120 HP and above. In 1996, India had a total fishing fleet of 238 125 units comprising 160 000 traditional craft, 31 726 motorized craft (converted from traditional) and 46 918 mechanized vessels operating different gear combinations. For artisanal fishing, the use of canoe and boat seine in Kerala provided the highest net income of Rs0.10 lakh with an annual catch of 51 t and an initial investment of Rs0.85 lakh. In motorized fishing, canoe and ring seine in Kerala offered a net income of Rs0.98 lakh with an annual catch of 220 t and an initial investment of Rs5.0 lakh. All major fishing units in Kerala, Tamil Nadu and Gujarat have higher profits not because of higher levels of fish catch but due to a better fish price. In the motorized sector, the increase in the price of fish over the years is greater than the increase in fuel expenditure. Small trawlers, purse seiners, dol-netters, gillnetters, pair trawlers and sona boats are the major types of mechanized fishing units operating in the inshore waters (up to 50 m depth). Trawlers and gillnetters are mostly operated along the Indian coasts whereas the fishing fleet mentioned above is confined to certain regions only. A small trawler (32Æ - 36Æ) has a net income of Rs0.90 lakh with an annual catch of 72 t and initial investment of Rs5.2 lakh in Karnataka. A purse seiner has a net earning of Rs3.14 lakh per year with an annual catch of 280 t and an average investment of Rs10 lakh. However the average value of fish caught in a purse seiner is Rs4.29 per kg set against the break-even cost of Rs3.16 per kg. To assess the economic sustainability of Indian marine fisheries in the period 1985 to 1998, the surplus production model or Schaefer Model was applied. Based on this, the maximum sustainable yield (MSY) was estimated at 2 353 726 t with an estimated effort of 984 586 annual fishing hours (AFH). Using the Fox surplus production model, MSY was equal to 2 973 752 t with an effort of 6 126 232 AFH. Note that actual yield during that period was 2 441 043 t with an effort of 12 97 092 AFH. This is indicative of over-fishing in the Indian Sea and Bay of Bengal. A number of management strategies can be applied to reduce the fishing pressure on the coastal areas of India. These are: (a) a ban of certain fishing gear and restricted entry to over-exploited fishing grounds; (b) the promotion of alternative/subsidiary income and emphasizing the importance of mariculture/aquaculture; (c) effective implementation of small scale fishery development projects like infrastructure and service facilities; (d) coastal zone management including protection of marine habitats; and (e) information dissemination and education on the importance of fisheries resources.Fishery resources, Fishery surveys, Biomass, Population density, Shrimp fisheries, Catch/effort, Trawling, Mathematical models, Coastal fisheries, Marine fisheries, Ecosystems, Socioeconomic aspects, Artisanal fishing, Ecnonomic benefits, ISW, India,

Marine fisheries along the southwest coast of India

Marine fisheries production in India has increased from 0.5 million t in 1950 to 2.47 million t in 1997. The gross value of fisheries landings in India was US$2.37 billion in 1997. The contribution of fisheries to the Gross Domestic Product (GDP) has risen from 0.7% in 1980 - 81 to 1.2% in 1994 - 95. The contribution to agricultural GDP has risen from 1.9% to 4%. Fisheries production also plays a critical role in food security and livelihood in rural areas. The southwest (SW) coast, while only 16% of the Indian coastline, is an important area for marine fisheries production, contributing 31.7% (0.74 million t) in 1993 - 98. This production is dominated by pelagic (59% of landings) and demersal species (23%). However, the open access system has resulted in rapid increases in fishing effort, particularly in the coastal areas. The density of fishers inshore has increased from 3.6 to 8.5 fishers per km2 in the past four decades. This excess effort has resulted in overfishing of the stocks and lower economic rent from the fishery. The overall objective of coastal fisheries management along the southwest coast of India is sustainable coastal fisheries development. This requires key ecological, social, economic and administrative issues to be addressed. Ecological sustainability requires the reduction of the excess effort through limited entry and effort reduction schemes, appropriate exploitation patterns through improved gear selectivity and restoration of the degraded coastal environment through integrated coastal zone management initiatives. Key social interventions include: creation of alternative employment to reduce fisher numbers, prevention/management of increasing intra- and inter-sectoral conflicts and empowerment of artisanal fishers through co-management schemes, social legislation and improved support/welfare schemes. The key economic issues include declining earnings, particularly of artisanal fishers, which requires; optimizing fleet composition for economic returns, improvement of the marketing system and cold storage chains, improvement of post-harvest processes to increase product value. The key administrative needs are a strong fisheries policy that balances welfare concerns with sustainability, effective implementation of regulations, and increased government resources for fisheries management. Project briefs covering the key interventions are provided, however these require further review and improvement in collaboration with concerned stakeholders.Fishery resources, Catch/effort, Population characteristics, Coastal fisheries, Marine fisheries, Ecosystems, Economic benefits, Fishery industry, Capture fishery economics, Fish consumption, Fishery policy, Legislation, Fishery management, Flood plains, Demersal fisheries, Pelagic fisheries, Socioeconomic aspects, Surveys, Marketing, Fish storage, Fishing gear, ISW, India,

Estimates of optimum fleet size for the exploited Indian shelf fisheries

A characteristic feature of marine fish production in India is its annual fluctuations, as vividly shown by the statistics of production for the past four decades. Marine fisheries still remain open access and suffer from overcapitalization. About 2,43,000 fishing vessels (1,82,096 artisanal craft, 26,171 motorised craft and 34,571 mechanised craft) exploit this area, where the estimated annual potential is 2.2 million, tonnes. A conservative estimate of investment on fishing implements (craft as well as gear), at current prices is about Rs. 33.4 billion, but the return per unit investment seems hardly viable. Unhealthy competition and unregulatedfishing may decimate the exploited stocks and therefore, the question of decidingthe optimum size of fishing fleets which wouldallow sustainable yields becomes very relevant

2-(3-Eth­oxy-2-hy­droxy­benz­ylidene)-N-phenyl­hydrazinecarboxamide

The title compound, C16H17N3O3, exists in the E configuration with respect to the azomethine double bond. The mol­ecule is close to planar, with a dihedral angle of 6.7 (1)° between the aromatic rings. The phenolic O atom functions as donor and acceptor by forming intramolec­ular O—H⋯O and inter­molecular N—H⋯O hydrogen bonds, respectively. Two-dimensional packing is fashioned through an inter­molecular hydrogen bonding network in an offset manner

THE EFFECTS OF FIELD EMITTED ELECTRONS ON RF SURFACE

The ever-growing demand for higher RF gradients has considerably increased the risk of breakdown in accelerating structures. Field emission is the most common form of RF breakdown that generates free electrons capable of inflicting irreversible damages on the RF surface. This paper presents a systematic experimental and simulation programme to understand possible sources and their influence on RF cavity operatio