Effects of human activities on migratory waterbirds at Lashihai Lake, China

Surveys on migratory waterbirds and their habitats at Lashihai Lake, China, were conducted from October 1999 to April 2000. Five fixed points, representing different degrees of habitat disturbance and quality, were selected around the lake. We used counts (n = 30) to compare diversity and abundance of waterbirds at each point and evaluate the effects of habitat disturbance. The distribution of waterbirds was affected by disturbance, with snore than one-third of the total species and nearly half of the total individuals occurring at the least disturbed point. Species richness was weakly and abundance was strongly correlated to habitat disturbance, but not to habitat quality. Habitat destruction and use of canoes were prominent at the lake. Naxi ethnic fishermen (n = 37) were interviewed. They caught 570 waterbirds between October 1999 and March 2000 in fishing nets. An estimation of the total number of waterbirds been trapped on the lake is 6164. Diving species were most susceptible. Conservation measures that should implement immediately include the cessation of habitat destruction, better plan for the development of tourism, a reduction in the number of canoes and zoning of the non-fishing area. (C) 2002 Elsevier Science Ltd. All rights reserved.

An idealized rural coastal zone management integrating land and water use

Various countries have formulated special integrated coastal zone management (ICZM) strategies which seek to both manage development and conserve natural resources and integrate and coordinate the relevant people sectors and their functions and roles within the bounds of this rich realm. Concerns that may be addressed by ICZM include: 1) Natural resources degradation; 2) Pollution; 3) Land use conflicts; and, 4) Destruction of life and property by natural hazards. Some prevalent sources of environmental impacts (livelihoods) are listed, together with some recommendations to the concerns which they may raise in relation to coastal zone management: agriculture; aquaculture; fisheries; forestry; human settlements; tourism; and, transport industry.

Sustainability in aquaculture

Sustainable aquaculture in Asia is discussed, considering in particular the loss of mangroves associated with the rapid increase in production of cultured shrimp. Southeast Asia's development and population growth brought non-sustainable exploitation of its coastline; the destruction has increased through the years as development proceeded and the international markets entered the scenario. An outline is given of the current status of mangroves in some Asian countries. Some worldwide remedies for sustainable aquaculture are described.

Crocodile farming: a multi-million dollar industry

Crocodiles have a long breeding life, which ranges from 25-30 years. There are 27 species and subspecies of crocodiles throughout the world, 18 of which are in danger of extinction, the rest being threatened with declining population due to overhunting and habitat destruction. Two known crocodile species exist in the Philippines: Crocodylus mindorensis (freshwater crocodile) and C. porosus (saltwater crocodile). Killing adult crocodiles, as is being done now, drastically reduces the potential population. Moreover, toxic wastes from mines, destruction of marshes and riverine habitats, and the conversion of their natural habitats for fishponds additionally threaten their populations. Estimates indicate that there are only about 100 Philippine crocodiles in the wild now. The Crocodile Farming Institute (CFI) was established in Palawan, in 1987, in order to save the crocodiles from extinction in the Philippines. It is now one of the components of the Palawan Wildlife and Conservation Center, and aims to conserve the 2 endangered species in the Philippines and also to develop and introduce a suitable crocodile farming technology that will help uplift the socio-economic well-being of the Filipino people. CFI believes in the potential of commercial utilization of crocodiles as a dollar-generating industry for the Philippines. It is a very profitable business and could be a multi-million dollar industry. A brief outline is given of the economic and marketing potentials of farming crocodiles in the Philippines.

Implications of changes in trophic diversity and food webs on fisheries and the environment

Most of the earth's ecosystems are experiencing slight to catastrophic losses of biodiversity, caused by habitat destruction, alien species introduction, climate change and pollution (Wilcove et al., 1998). These human effects have led to the extinction of native fish species, the collapse of their populations and the loss of ecological integrity and ecosystem functioning (Ogutu-Ohwayo & Hecky, 1991; Witte et al. , 1992a; Mills et al., 1994; Vitousek et al., 1996). Food webs are macro-descriptors of community feeding interactions that can be used to map the flow of materials and nutrients in ecosystems (Jepsen & Winemiller, 2002). Comparative food web studies have been used to address theoretical questions such as 'does greater trophic connectivity increase stability?' (Cohen et al., 1990), and 'does the number of trophic levels increase with productivity?' (Briand & Cohen, 1987). Answers to such questions have obvious applications for natural resources management. From a multi-species fisheries standpoint, there is a need to understand consumer-resource dynamics within complex trophic networks.

A new species of Henneguya (Myxosporida, Protozoa) from West African catfish, Clarias lazera Val., with a review of the genus Henneguya Thelohan, 1892

A new species of myxosporida, Henneguya clariae, is described from the gills of Claria’s Iazera caught from various waters in Nigeria. Pathogenic effects in the destruction of the components of the branchial system are about 25% of Clarias lazera. A review of the genera Henneguya myxobilatus, and Neohenneguya is made and these were synonymised, with some reservations in the case of to Henneguya. A checklist of the genus Henneguya is given.

La reproducción de la merluza en el Mar Argentino (Merlucciidae, Meluccius merluccius hubbsi) : 1. Descripción histológica del ciclo del ovario de merluza

The present paper deals on the histological description of the hake ovary made on the basis of gonad observations of 394 females during the period April 1966 March 1967. The material was obtained from weekly sampling of commercial catches carried out at the Institute of Marine Biology (Prov. Buenos Aires, Argentina). The anatomical and histological description of the standard ovary and the adopted terminology are given. The maturation process is divided into five periods, from ovocyte formation to yolked ovocyte formation, with its histological description. Ovary changes are analyzed on detail. The following conclusions were outlined: 1. Analysis demonstrated that although some specimens were totally spawned others, at the end of the spawning period, retaining a great number of ovocytes in different maturity stages. Therefore, postspawners have been classified as follows: Postspawned II : This stages is characterized by the empty ovarian structure, with ovocytes in stage II, which will remain in the resting phase untill next spawning season. Postspawned III and IV: Their main characteristics are: tissue destruction, bloody residuals and remaining ovocytes in stage III and IV, respectively. 2. Some transformations were found in ovaries of postspawned III and IV. They are classified as follows, according to its origin and structure: Developed from follicular cell membrane – a) Glandular formations, b) Epiteloid formations - Originated from remaining ovocytes, c) Ovocyte disintegration, d) Ovocyte with follicular cell infiltration. 3. All those structures derived from postpawners III and IV have a temporary character and will be reabsorbed. Their presence delay the recuperation of the organ and its reproductive functions. Consequently, the possibility of those structures acting as control mechanisms is suggested. 4. Transformations pointed out in paragraph Nº 2 prevent the possibility of consecutive spawning originated from the remaining ovocytes (II and IV). 5. No structures originated from postspawners III and IV were found during summer season. 6. Reproductive cycle of hake has been described monthly. It was observed that maturing ovaries predominate in summer (November-December).

Methodology for valuing wetlands in Uganda

The wetlands in Uganda are undergoing rapid degradation. Swamps provide a habitat for birds, fishes and other animals. They have many ecological functions and, furthermore, supply people with multiple resources, such as reeds, herbs, fish and agricultural products. Although some'uses of wetland are sustainable, others lead to rapid deterioration. The main threat to swamps are human activities. One reason for the progressive destruction of wetlands is that the people may not appreciate the existence of and the treasures represented by wetlands even if they live in arm long distance from them. Another reason is that the two most important user groups of wetlands, farmers and fishermen, although having conflicting interests concerning the wetlands, hardly interact. A study, done as part of the Ecotone Project at the Fisheries Research Institute (FIRI), tries to evaluate in monetary terms how much Uganda loses with progressive destruction of wetlands. The study looks first at which uses of the wetlands are of importance and thereafter it examines, what data is needed and available to calculate the values of those uses.

The role of satellite lakes in conservation of fish species diversity in the Lake Kyoga basin

Lakes Victoria and Kyoga had, a diverse fish fauna, which was important as food for local population and valuable in scientific studies. Over the past twenty years, the diversity of fish in these lakes had declined due to over-exploitation, introduction of new fish species including the piscivorous Nile perch and degradation of fish habitat. Studies of satellite lakes in the Victoria and Kyoga lake basins suggested that some of these lakes harboured species which had been lost from the main lakes. In order to better understand the extent, to which these satellite lakes may serve as refugia, a faunal survey was undertaken to determine the distribution and nature of the taxa found. Seven satellite lakes and the eastern end of the main Lake Kyoga adjacent to these minor lakes were surveyed over a two-year period for fish species diversity. A total of 68 fish species were recorded of which 41 were haplochromines. Almost all the native non cichlids which occurred in the main lakes (Victoria and Kyoga) before the Nile perch upsurge recorded. Lakes Nawampasa, Gigati, Kawi, Agu and Nyaguo had the highest fish species and trophic diversity. The trophic diversity of haplochromines (based on Shannon Weaver Index) was highest in Lake Nawampasa (1.28), followed by Gigati (1.25), Kawi (1.18), Agu (0.8), Lemwa (0.81), Nyaguo (0.35) and was lowest in the main Lake Kyoga. Potential threats to these lakes were from collectors of ornamental fish species, especially the haplochromines, the spread of the predatory Nile perch and the water hyacinth, which are already in Lake Kyoga, and the destruction of macrophytes through harvesting of papyrus and reclamation for agriculture. The human population around these lakes harvested the fishes for food but the levels of exploitation were still low because the lakes were adjacent to main Lake Kyoga, the major supply of fish. Ornamental fish dealers were encouraged to start captive breeding of the fish for export to reduce pressure on the lakes and demonstrations for breeding were set up at FIRI in Jinja. Meetings and seminars were held with some of the communities living around the lakes sampled and the importance of fish species found in these lakes and the dangers of destructive practices discussed. Representatives of all taxa of fish caught from the lakes were preserved, catalogued and stored in the FIRI Museum. Results from this survey support the motion that these satellite lakes are important refugia for endemic diversity. Based on survey, we recommend that SaIne of these lakes like Nawampasa, Gigati, Kawi, Agu and Nyaguo could be designated as conservation areas of species threatened in the main lakes. One of the factors that seem to have prevented the spread of Nile perch into Kyoga Minor lakes seems to have been the presence of extensive swamps around these lakes and the low oxygen levels that exist in these habitats. Clearing of swamps and vegetation that separate Kyoga minor lakes from the main lake should be avoided to prevent Nile perch from spreading into these lakes.

Turn-off failure mechanism in large area IGCTs

The destruction mechanism in large area IGCTs (Integrated Gate Commutated Thyristors) under inductive switching conditions is analyzed in detail. The three-dimensional nature of the turn-off process in a 91mm diameter wafer is simulated with a two-dimensional representation. Simulation results show that the final destruction is caused by the uneven dynamic avalanche current distribution across the wafer. © 2011 IEEE.

Cinematographic OH-PLIF measurements of two interacting turbulent premixed flames with and without acoustic forcing

This paper describes an experimental investigation into the interactions that occur between two lean turbulent premixed flames stabilised on conical bluff-bodies when they are moved closer together. Cinematographic OH-PLIF measurements were acquired to investigate adjacent flame front interactions as a function of flame separation distance (S). Flame surface density (FSD) and curvature were determined to characterise the unforced flames. Acoustic forcing was then applied to explore the amplitude dependent thermo-acoustic response. Phase-averaged FSD and global heat release measurements in the form of OH * chemiluminescence were obtained for a range of forcing frequencies (f) and amplitudes (A) as a function of S. As the flames were brought closer together the adjacent annular jets were found to merge into a single jet structure. This caused adjacent flame fronts to merge above the wake region between the two flames at a location determined by the jet efflux (flame angle) and S. This region of flame-flame interaction we refer to as 'interacting region'. In the unforced flames, a trend of increasingly negative curvature for decreasing S produced a small net increase in flame surface area via cusp formation. When subjected to acoustic forcing, S-dependent regimes were found in the global heat release response as a function A. The overall trend showed that the occurrence of jet/flame merging reduces the value of A at which non-linear response occurs. In support of previous findings for flames stabilised along shear layers, the phase-averaged FSD showed that the flame dynamics that drive the thermo-acoustic response result from the roll-up of vortices which generate large-scale vortex-flame interactions. Compared with axisymmetric flames, the occurrence of jet merging alters the vortex-flame interactions resulting in an asymmetric contribution to the heat release between the wall and interacting regions. The majority of the heat release was found to occur in the interacting region through the rapid production and destruction of flame surface area. The occurrence of jet merging and large-scale interactions between adjacent flames result in different physical mechanisms that drive the thermo-acoustic response compared with single axisymmetric flames. © 2011.

Bird and mammal conservation in Gaoligongshan Region and Jingdong County, Yunnan, China: patterns of species richness and nature reserves

Elevational and latitudinal patterns of species richness for birds and mammals were compared with human population density in relation to nature reserve designation in two areas of Yunnan Province, China. Results suggest that species richness is not the same for the two areas. In Gaoligongshan Region, species richness is inversely correlated with elevation and altitude, while reserve designation is positively correlated with elevation and latitude. In Jingdong County, reserve designations are positively correlated with elevation, but species richness shows no clear trends. In general, the present situation is strongly influenced by human activities. It appears that reserve designation is mismatched with species richness in Gaoligongshan Region, while there is a better fit between the two in Jingdong County. In both areas, however, it appeared that reserves were located primarily in order to reduce conflict with humans rather than to maximize conservation of biodiversity, probably because humans were responsible for forest-especially primary forest-destruction and degradation in the low-lying areas.

Habitat degradation of Rhinopithecus bieti in Yunnan, China

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.

Detailed design of242mAm breeding in pressurized water reactors

There is growing interest in the use of 242mAm as a nuclear fuel. Because of its very high thermal fission cross section and its large number of neutrons released per fission, it can be used for various unique applications, such as space propulsion, medical applications, and compact energy sources. Since the thermal absorption cross section of 242mAm is very high, the best way to obtain 242mAm is by the capture of fast or epithermal neutrons in 241Am. However, fast spectrum reactors are not readily available. In this paper, we explore the possibility of producing 242mAm in existing pressurized water reactors (PWRs) with minimal interference in reactor performance. As suggested in previous studies on the subject, the 242mAm breeding targets are shielded with strong thermal absorbers in order to suppress the thermal neutron flux that causes 242mAm destruction. Since 242mAm enrichment within the Am target mainly depends on the neutron energy distribution, which in turn depends on the Am target thickness and on the neutron filter cutoff energy (thermal absorber type), this unique Am target design was developed. In our study, Cd, Sm, and Gd were considered as thermal neutron filters, as suggested by Cesana et al. The most favorable results were obtained by irradiating Am targets covered either with Gd or Cd. In these cases, up to 8.65% enrichment of 242mAm is obtained after 4.5 yr (three successive PWR fuel cycles) of irradiation. It was also found that significant quantities [up to 1.3 kg/GW (electric)-yr] of 242mAm can be obtained in PWR reactors without notable interference with reactor performance. However, in order to maintain the original fuel cycle length, the enrichment of the driver (UO2) fuel must be increased by ∼1%, raised from the conventional 4.5 to 5.5%, depending on the thermal neutron filter used. The most important reactivity feedback coefficients for fuel assemblies containing the 242mAm breeding targets were evaluated and found to be close to those of a standard PWR. Another product of neutron capture in the 241Am reaction is 238Pu. It was found that in a typical 1000 MW (electric) PWR core with one-third of the fuel assemblies containing 241Am targets, up to 15.1 kg of 238Pu enriched to 80% can be produced per year.

The effect of Ln(III)/An(III) separation on TRU multi-recycling in CONFU assembly

This work examines the basic feasibility of the net-zero-balance TRU multi-recycling concept in which trivalent lanthanide fission products (Ln(III) ) are not separated from trivalent actinides (An(III)). The TRU together with Eu and Gd isotopes are recycled in a standard PWR using Combined Non-Fertile and UO2 (CONFU) assembly design. The assembly assumes a heterogeneous structure where about 20% of U02 fuel pins on the assembly periphery are replaced with Inert Matrix Fuel (IMF) pins hosting TRU, Gd, and Eu generated in the previous cycles. The 2-D neutronic analysis show potential feasibility of Ln / An recycling in PWR using CONFU assembly. Recycling of Ln reduces the fuel cycle length by about 30 effective full power days (EFPD) and TRU destruction efficiency by about 5%. Power peaking factors and reactivity feedback coefficients are close to those of CONFU assembly without Ln recycling.