19 resultados para Totally Umbilical

em Aquatic Commons


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This report amplifies and refines some of the data already issued covering the water resources of Volusia County, which were published as Report of Investigations No. 21. The work in the report was accomplished as a cooperative program between the Department of Natural Resources, the U. S. Geological Survey and the Board of County Commissioners of Volusia County. Volusia County is almost totally dependent upon the water which falls upon the county and has a recharge area contained along the western portion and the central portions of the county. Excellent water is produced in the areal recharge and it is anticipated that this data will expand the existing knowledge of the water resources to permit the development of a great capacity for existing utilities and to offset and solve some of the problems now in the area. (PDF has 71 pages.)

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Whenever human beings have looked out on the sea, they have seen whales. First from the shore and later from ships when humanity entered the ocean realm as seafarers, we have responded to seeing these creatures with awe and wonder. Even when we hunted whales, a period well chronicled both in history and in literature, the sight of a whale brought an adrenaline rush that was not totally linked to potential economic gain. The first trips on boats specifically to watch, rather than hunt, whales began around 45 years ago in Southern California where the migrating gray whales, seen in the distance from land, drew vessels out for a closer look. Since that time whalewatching has boomed, currently conducted in over 40 countries around the world, including Antarctica, and estimated by economists at the Whale and Dolphin Conservation Society to have a 1999 worldwide economic value of around $800 million USD. The economic contribution to local coastal communities is particularly significant in developing countries and those where declining fish populations (and in some cases like the Japanese, international bans on whaling) have driven harvesters to look for viable alternatives. Clearly, whalewatching is now, in many places around the world, a small but thriving part of the regional economy. Like in the days of whaling, we still get the rush, but for some, money is back contributing to the physiological response. (PDF contains 90 pages.)

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Pelagic juvenile rockfish (Sebastes spp.) collected in surveys designed to assess juvenile salmonids and other species in the Gulf of Alaska in 1998 and 2000–2003 provide an opportunity to document the occurrence of the pelagic juveniles of several species of rockfish. Often, species identification of rockfish is difficult or impossible at this stage of development (~20 to 60 mm), and few species indigenous to Alaska waters have been described. Use of mitochondrial DNA markers for rockfish species allowed unequivocal identification of ten species (S. aleutianus, S. alutus, S. borealis, S. entomelas, S. flavidus, S. melanops, S. pinniger, S. proriger, S. reedi, and S. ruberrimus) in subsamples from the collections. Other specimens were genetically assignable to groups of two or three species. Sebastes borealis, S. crameri, and S. reedi were identified using morphological data. Combining genetic and morphological data allowed successful resolution of the other species as S. emphaeus, probably S. ciliatus (although S. polyspinis cannot be totally ruled out), and S. polyspinis. Many specimens were initially morphologically indistinguishable from S. alutus, and several morphological groups included fish genetically identified as S. alutus. This paper details the characteristics of these pelagic juveniles to facilitate morphological identification of these species in future collections. (PDF file contains 32 pages.)

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Some 25 to 30 yr ago, when we as students were beginning our respective careers and were developing for the first time our awareness of marine mammals in the waters separating western North America from eastern Asia, we had visions of eventually bridging the communication gap which existed between our two countries at that time. Each of us was anxious to obtain information on the distribution, biology, and ecological relations of "our" seals and walruses on "the other side," beyond our respective political boundari~s where we were not permitted to go to study them. We were concerned that the resource management practices on the other side of the Bering and Chukchi Seas, implemented in isolation, on a purely unilateral basis, might endanger the species which we had come to know and were striving to conserve. At once apparent to both of us was the need for free exchange of biological information between our two countries and, ultimately, joint management of our shared resources. In a small way, we and others made some initial efforts to generate that exchange by personal correspondence and through vocal interchange at the annual meetings of the North Pacific Fur Seal Commission. By the enabling Agreement on Cooperation in the Field of Environmental Protection, reached between our two countries in 1972, our earlier visions at last came true. Since that time, within the framework of the Marine Mammal Project under Area V of that Agreement, we and our colleagues have forged a strong bond of professional accord and respect, in an atmosphere of free intercommunication and mutual understanding. The strength and utility of this arrangement from the beginning of our joint research are reflected in the reports contained in this, the first compendium of our work. The need for a series of such a compendia became apparent to us in 1976, and its implementation was agreed on by the regular meeting of the Project in La Jolla, Calif., in January 1977. Obviously, the preparation and publication of this first volume has been excessively delayed, in part by continuing political distrust between our governments but mainly by increasing demands placed on the time of the contributors. In this period of growing environmental concern in both countries, we and our colleagues have been totally immersed in other tasks and have experienced great difficulty in drawing together the works presented here. Much of the support for doing so was provided by the State of Alaska, through funding for Organized Research at the University of Alaska-Fairbanks. For its ultimate completion in publishable form we wish to thank Helen Stockholm, Director of Publications, Institute of Marine Science, University of Alaska, and her staff, especially Ruth Hand, and the numerous referees narned herein who gave willingly oftheir time to review each ofthe manuscripts critically and to provide a high measure of professionalism to the final product. (PDF file contains 110 pages.)

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The herring of the Baltic Sea shows a complicated population structure. Comparable to herring in other areas it can also be discriminated as spring and autumn spawning herring. Autumn spawning herring has been nearly vanished since the late 1960’s. Baltic Sea spring spawning herring show a broad variety as far as morphometric and other biological characteristics are concerned. It seems not very likely that all those differences are genetically based. The spawning sites of populations are, however, often clearly separated and such groups of herring are in most cases characterized by distinct differences in individual growth. Therefore for assessment purposes it is necessary to distinguish between as small as possible units in order to not endanger smaller populations to become extinct by overexploitation. On the other hand migrations and mixing of herring of different origin especially during the summer feeding period result in extreme difficulties of the discrimination of small units. For this reason only three herring assess ment units have been identified for the central and the northern Baltic Sea: herring in Sub-divisions 25–32+32, herring in Sub-division 30 and herring in Sub-division31. The spring spawning herring of the western Baltic Sea has been combined with spring spawning herring in Division IIIa. Only the herring stock in Sub-division 30 shows a positive development in the past. The largest assessment unit in Sub-divisions 25–29+32 decreased continuously during the whole period 1974–1998. The western Baltic Spring spawning herring stock decreased from 1990 to 1996. There is an ongoing debate on scientific level whether the combination of small populations into large assessment units like the one in S-D’s 25–29&32 might include the danger of the extinction of small compartments of the unit. On the other hand the practice by the International Baltic Sea Fishery Commission of managing the Baltic Sea herring fisheries by dividing a yearly Total Allowable Catch for the whole area among fishery zones without taking care of any biological structure and any individual stock development is totally against the idea of sustainability of fisheries.

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Two landing sites were chosen in Tanzania for the 4-beaches survey. The former, Ihale, is a large one with an avarage of 120 boats and direct connections to the fish processing factories. The latter, Mwasonge, is one of the smallest landing sites in the Mwanza region with totally different characteristics. This book section aims to analyse the results from these two sites in the context of the co-management potentialities in Tanzania and more generally on the Lake Victoria region.

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Three diets were formulated using locally available feed ingredients in Malawi to test the effect of replacing animal protein (fish meal, meat and bone meal) with soybean meal (10:0, 5:5, 0:10% of diet) as the protein source on growth and feed conversion of Oreochromis karongae. There were no significant differences in growth rate (GR), specific growth rate (SGR) and feed conversion ratios (FCR) among the three diets. It can be concluded that more expensive and limited animal protein sources can totally be replaced by cheaper soybean in order to get similar growth rates in O. karongae.

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TOPIC 1: In terms of seasonal scale, temperature effect dominates the annual change of steric height in the open ocean whereas salinity effect controls it along the continental shelf. Large portion of the annual change of height relative to the 1000-db surface is contained in the upper 100m layer. However, in interannual scale large anomalies of steric height in the open ocean, are more often than not, caused by halosteric rather than thermosteric effect. At least in the open ocean the heights are almost totally determined by the behavior of deep water. Their interannual variability appears to be related to the cumulative effect of Eckman pumping. TOPIC 2: There is a "trend" that over the past 28 years the water at Station P has warmed. Least-square analysis indicates that this warming may be significant but shortening of the time-series data by approximately 10 years fails to show that this is the case. These "trends" have to be interpreted with care. The warming may be "apparent" in that it is not indicated clearly in the deep isopynal surfaces which, during the above period, have deepened. Thus warming at the isobaric surfaces may be the effect of the downward migration of the isopynal surfaces.

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Common carp (Cyprinus carpio) eggs were incubated to study the efficiency of hatching in hapa and hatchery. During incubation the recorded temperature was 21-28 degree C and 20-31 degree C, dissolved oxygen 6-9 ppm. and 3-5 ppm., total alkalinity 180-250 ppm. and 28-62 ppm. respectively in the hatchery (model C.I.F.E. D-80) and hapa. CO sub(2) was totally absent in the hatchery, but recorded 3-10 ppm. in the hapa. The flow of water was maintained at 1.25 l/minute/jar in the hatchery. Under the above environmental conditions the eggs hatched in 42-51 hrs. in the hatchery and 61-81 hrs. in the hapa from egg to spawn thereby establishing the hatchery to be a better hatching system for carp eggs.

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The first FFDA in Orissa state was established in the year 1976. The study was conducted in Balasore district of the State. The findings revealed that all of the FEOs were not well qualified but trained and experienced. The duration of training obtained varied from 3 to 10 months. An FEO has a large area under his jurisdiction. Cycle was used by most of the FEOs to visit the fish farmers which resulted in infrequent visits. The FEOs were not satisfied with the working conditions, promotion avenues and conveyance facilities. There was interference of political bodies in leasing out ponds. The amount of loan sanctioned was not adequate to start fish farming. They also revealed that marketing aspects were totally neglected by the FFDA.

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Vertical distribution of intertidal molluscs in and around Mumbai had been studied. Each species has an upper and lower limit of distribution along the vertical intertidal gradient and are concentrated at particular levels or zones where they find optimum living conditions. Zonation of the intertidal area with reference to molluscs at rocky shores of TIFR, Bandstand and NCPA has similarities. However, there is no similarity in zonation among rocky, sandy and muddy shores. Rocky intertidal zones are more diverse and dense in terms of molluscs. The mid and lower littoral zones have rich diversity. The upper littoral zone at some sites, especially Girgaon chowpatty is totally devoid of molluscs due to anthropogenic activities. Gafrarium divaricatum, Nerita oryzarum, N. polita and Neritina crepidularia have established themselves in all three marked zones, indicating their power to adjust with the wide fluctuations in surrounding environmental conditions.

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Dehydroacetic acid and ammonia were found to be very effective in checking the growth of all the cultures at all concentrations tried. The two nitrofuran derivatives namely, semicarbazone and AF-2 were fairly effective, semicarbazone being more effective than AF-2. Sodium nitrite was found to be totally ineffective against the cultures at all concentrations tried.

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Occurrence and growth rates of two species of intertidal fouling bryozoans namely Electra bengalensis (Stoliczka) and Electra crustulanta (Pallas) are presented in this paper. The former was a typically marine form, settling on panels only during the high saline conditions of the pre-monsoon period and were absent during the low salinity conditions of the monsoon period, while the latter appeared to be a typical brackish water form settling on panels during the low saline conditions existing during the monsoon and post-monsoon periods and were totally absent during the pre-monsoon months. Regression co-efficient of the former was higher than that of the latter suggesting more pronounced growth in Electra bengalensis. Maximum growth for this species was noticed during March, April and May (pre-monsoon) while for the other species growth was more or less similar during monsoon and post-monsoon months (June-January) showing that the species was at home in oligohaline and mesohaline waters.

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Lethal and sub-lethal effects of mercury have been studied in Perna viridis and Modiolus carvalhoi. For P. viridis LC30 is 1.0 p.p.m. at 48 h and 0.23 p.p.m. at 96 h. Recorded LC50 values for M. carvalhoi are 0.5 p.p.m. and 0.19 p.p.m. at 48 h and 96 h respectively. The results document that these two species, although inhabiting the same area in the tidal belt, exhibit clear differences in mercury resistance. It is further shown that the duration of exposure affects mortality rates. In sub-lethal concentration, between 0.01 and 0.10 p.p.m. decrease in pedal-gland activity is conspicuous in P. viridis. At concentrations much below LC50 values (at 96 h), although some animals are alive, pedal-gland activity is totally suspended, supporting the assumption that shell closure ability plays a minor role in byssus thread production. In M. carvalhoi total cessation of pedal gland activity occurred at 0.09 p.p.m. of mercury.

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The present paper reviews critically the existing information on mangrove ecosystem of Saudi Arabian Red Sea coast and identifies problems and shortcomings that should be removed or remedied. Mangrove structure and composition seems to have been substantially studied along with salient environmental features, and these are thoroughly summarized herewith. However, the functional aspects, especially energy flow through the ecosystem, remain totally neglected. Both the flora and fauna indicate severe environmental conditions, such as very low nutrient levels, very high salinity values and hard bottom, which are unique to the area. Mangrove growth and diversity is very poor, although conditions in the southern part are relatively favourable. The extreme poverty of the ecosystem is supported by exports of organic matter from adjacent seaweed and seagrass ecosystems and also Sabakhas. Preponderance of epiphytic and benthic algae within the mangrove ecosystem is another source of nutrient replenishment in the otherwise oligotrophic habitat of Red Sea. Finally, a hypothetical model of energy flow in the ecosystem is proposed.