13 resultados para Big bath

em Aquatic Commons


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Leonard Carpenter Panama Canal Collection. Photographs: Dredging, Soldiers, and Ships. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

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(PDF contains 4 pages)

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(PDF contains 3 pages.)

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(PDF contains 5 pages.)

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(PDF contains 2 pages.)

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Slaughtering of eels should be done not only under animal welfare aspects but as well under consumer protection and economical aspects with respect to technical feasibility. Methods must be practicable for enterprises slaughtering quantities of several kilograms up to several tons per day. Most methods applied up to now in whole Europe were (are) not in accordance with animal welfare mainly due to lacking prescriptions and alternative methods. The great number of experiments carried out within the frame of this project demonstrates the difficulties to combine optimal welfare demands with economical and technical fesibility aspects in one method. Measurements of EEG (electroencephalogram) and ECG (electrocardiogram) have shown that the method laid down in the german legislation does not perfectly stun all eels. This method was improved by applying a „prestun“ with 220 V for 1sec., followed by a 5 min phase at 45 V to prolongue the time of unconsciousness after the stun. Inflating nitrogen gas into the stunning bath additionally causes asphyxia during the stun. By this method 93% of the eels were stunned or even killed. Applying 220 V for bigger batches of eels (~400 kg) will cause big problems with the energy supply. Therefore this method is restricted to batches of 20 - 50 kg. The method laid down in the german legislation probably can be improved. Eels were stunned successfully without water, avoiding the problems of regional differences in the conductivity of the water. Other types of current and other frequencies and a combination of both should be tested as well as alternative electrode geometries also with respect to blood spots which occasionally occurred in the muscles preferably of bigger eels (>800 g). For the time being the method laid down in the german legislation is a reasonable compromise and under animal welfare aspects represents a considerable improvement.

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Amphibian declines and extinctions have been documented around the world, often in protected natural areas. Concern for this trend has prompted the U.S. Geological Survey and the National Park Service to document all species of amphibians that occur within U.S. National Parks and to search for any signs that amphibians may be declining. This study, an inventory of amphibian species in Big Cypress National Preserve, was conducted from 2002 to 2003. The goals of the project were to create a georeferenced inventory of amphibian species, use new analytical techniques to estimate proportion of sites occupied by each species, look for any signs of amphibian decline (missing species, disease, die-offs, and so forth.), and to establish a protocol that could be used for future monitoring efforts. Several sampling methods were used to accomplish these goals. Visual encounter surveys and anuran vocalization surveys were conducted in all habitats throughout the park to estimate the proportion of sites or proportion of area occupied (PAO) by each amphibian species in each habitat. Opportunistic collections, as well as limited drift fence data, were used to augment the visual encounter methods for highly aquatic or cryptic species. A total of 545 visits to 104 sites were conducted for standard sampling alone, and 2,358 individual amphibians and 374 reptiles were encountered. Data analysis was conducted in program PRESENCE to provide PAO estimates for each of the anuran species. All of the amphibian species historically found in Big Cypress National Preserve were detected during this project. At least one individual of each of the four salamander species was captured during sampling. Each of the anuran species in the preserve was adequately sampled using standard herpetological sampling methods, and PAO estimates were produced for each species of anuran by habitat. This information serves as an indicator of habitat associations of the species and relative abundance of sites occupied, but it will also be useful as a comparative baseline for future monitoring efforts. In addition to sampling for amphibians, all encounters with reptiles were documented. The sampling methods used for detecting amphibians are also appropriate for many reptile species. These reptile locations are included in this report, but the number of reptile observations was not sufficient to estimate PAO for reptile species. We encountered 35 of the 46 species of reptiles believed to be present in Big Cypress National Preserve during this study, and evidence exists of the presence of four other reptile species in the Preserve. This study found no evidence of amphibian decline in Big Cypress National Preserve. Although no evidence of decline was observed, several threats to amphibians were identified. Introduced species, especially the Cuban treefrog (Osteopilus septentrionalis), are predators and competitors with several native frog species. The recreational use of off-road vehicles has the potential to affect some amphibian populations, and a study on those potential impacts is currently underway. Also, interference by humans with the natural hydrologic cycle of south Florida has the potential to alter the amphibian community. Continued monitoring of the amphibian species in Big Cypress National Preserve is recommended. The methods used in this study were adequate to produce reliable estimates of the proportion of sites occupied by most anuran species, and are a cost-effective means of determining the status of their populations.

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The natural history of Tarpon atlanticus (Valenciennes 1846) is reconstructed based on published information. Tarpon is a remarkable fish because of its peculiar larvae, large adult size, migration patterns and its capability to breathe atmospheric air. Destructive fisheries - some using dynamite - have much reduced the population of tarpon along the Caribbean coast of Colombia, and some catch data are presented which document this.

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This is the Cheshire stillwaters. Summary results of 1997 data Oak Mere, Betley Mere and Marbury Big from the National Rivers Authority, June 1998. In May 1997, a Stillwaters meeting was held to discuss the way forward in stillwaters monitoring. It decided upon the establishment of a three year rolling programme, in which three stillwaters would be monitored three times a year, every third year. The stillwaters where chosen due to water quality (i.e potential polluted / sensitive waters), fisheries and ecological interests. The Still waters chosen for the first year (1997) were Oak Mere, Betley Mere and Marbury Big Mere. The surveys were aimed to produce a comprehensive study of the still water through monitoring a variety of parameters. Algal, zooplankton and water chemical samples were taken three times a year, (April, July and September). In addition, fisheries surveys were taken in July and marginal invertebrate surveys taken in September.

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Copper is used to deter the growth of bacterial, fungal and protozoan disease organism in fishes. Zoeae (Z SUB-1 ), myses (M SUB-1 ) and postlarvae (P SUB-1 ) were exposed to copper sulfate at concentrations of 0 . 025, 0 . 05, 0 . 75, 0 . 1 and 0 . 2 ppm from 24 to 96 hours. The number of surviving larvae were counted at the end of each 24-hour period and the percentage of survival is determined for each dose level. The LC SUB-50 for each of the larval stages was interpolated from the data whenever possible. Three trials with 2 replicates per trial were conducted. The physico-chemical characteristics of the bath taken before and at the end of the experimental period show insignificant differences between initial and final values in each trial. Results indicate that mortality rates of all larval stages increased with exposure time and that mortality rates of the experimental group is higher than the control. Interpolation of the LC SUB-50 is possible only for the 48-h and 72-h exposure times for both zoeae and myses and for the 48-h exposure time for the postlarvae. This is due to the high survival percentage of the 24-h group and the low survival percentage (below 50%) of the larvae exposed for 96 hours. The 48-hour LC SUB-50 for Z SUB-1 , M SUB-1 and P SUB-1 are 0 . 225, 0 . 350 and 0 . 125 ppm respectively. Postlarvae seem to be more sensitive than either of the 2 larval stages having a lower 48-h LC SUB-50 and a low survival rate after 72 hours. The larvae were observed to lose their balance and were lethargic, producing few swimming movements so that they were mostly confined to the bottom of the aquaria. Moribund larvae observed under the microscope had a faster but weak heartbeat compared to healthy larvae. Slight or complete loss of feeding ability indicated by empty guts and delayed molting of Z SUB-1 to Z SUB-2 were also noted.