16 resultados para Review Of Other Organisms

em Aquatic Commons


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Marine reserves, often referred to as no-take MPAs, are defined as areas within which human activities that can result in the removal or alteration of biotic and abiotic components of an ecosystem are prohibited or greatly restricted (NRC 2001). Activities typically curtailed within a marine reserve are extraction of organisms (e.g., commercial and recreational fishing, kelp harvesting, commercial collecting), mariculture, and those activities that can alter oceanographic or geologic attributes of the habitat (e.g., mining, shore-based industrial-related intake and discharges of seawater and effluent). Usually, marine reserves are established to conserve biodiversity or enhance nearby fishery resources. Thus, goals and objectives of marine reserves can be inferred, even if they are not specifically articulated at the time of reserve formation. In this report, we review information about the effectiveness of the three marine reserves in the Monterey Bay National Marine Sanctuary (Hopkins Marine Life Refuge, Point Lobos Ecological Reserve, Big Creek Ecological Reserve), and the one in the Channel Islands National Marine Sanctuary (the natural area on the north side of East Anacapa Island). Our efforts to objectively evaluate reserves in Central California relative to reserve theory were greatly hampered for four primary reasons; (1) few of the existing marine reserves were created with clearly articulated goals or objectives, (2) relatively few studies of the ecological consequences of existing reserves have been conducted, (3) no studies to date encompass the spatial and temporal scope needed to identify ecosystem-wide effects of reserve protection, and (4) there are almost no studies that describe the social and economic consequences of existing reserves. To overcome these obstacles, we used several methods to evaluate the effectiveness of subtidal marine reserves in Central California. We first conducted a literature review to find out what research has been conducted in all marine reserves in Central California (Appendix 1). We then reviewed the scientific literature that relates to marine reserve theory to help define criteria to use as benchmarks for evaluation. A recent National Research Council (2001) report summarized expected reserve benefits and provided the criteria we used for evaluation of effectiveness. The next step was to identify the research projects in this region that collected information in a way that enabled us to evaluate reserve theory relative to marine reserves in Central California. Chapters 1-4 in this report provide summaries of those research projects. Contained within these chapters are evaluations of reserve effectiveness for meeting specific objectives. As few studies exist that pertain to reserve theory in Central California, we reviewed studies of marine reserves in other temperate and tropical ecosystems to determine if there were lessons to be learned from other parts of the world (Chapter 5). We also included a discussion of social and economic considerations germane to the public policy decision-making processes associated with marine reserves (Chapter 6). After reviewing all of these resources, we provided a summary of the ecological benefits that could be expected from existing reserves in Central California. The summary is presented in Part II of this report. (PDF contains 133 pages.)

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The paper introduces the tilapias as important culture fish; their classification, breeding habits and general ecology are discussed. The versatility and plasticity of their reproduction and growth are major advantages as well as draw backs in their use as culture species. The culture of tilapias in ponds, cages, pens and raceways are described and a comparison of extensive and intensive cultivation is made. The major factors in commercial cultivation of tilapias such as feeds, hatchery/fry production and disease control are discussed. Recommendation is made for the consideration of tilapia as the equivalent of the common carp in tropical African fish culture in either monoculture or in polyculture with other fish species

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ENGLISH: This report reviews the Japanese longline fishery for tunas and billfishes in the eastern Pacific Ocean during 1971-1980, extending the studies made by other investigators, which covered the 1956-1970 period. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for each species. The deep longlining method is described and the hook rates for this gear and for conventional longline gear are compared. Some observations on the interaction of surface and longline gear are reported. SPANISH: Se examina en este informe la pesca palangrera japonesa de atunes y peces espada en el Océano Pacífico oriental durante 1971-1980, ampliando los estudios hechos por otros investigadores que incluían el período de 1956-1970. Para cada especie se examinan las distribuciones temporales y espaciales del esfuerzo de pesca, captura, abundancia aparente, madurez sexual y composición de talla. Se describe el método de los palangres profundos y se comparan los índices de captura por anzuelo de este arte y del arte convencional palangrero. Se presentan algunas observaciones sobre la interacción de las artes espipelágicas y las palangreras. (PDF contains 163 pages.)

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ENGLISH: This report reviews the activity of the Japanese longline fishery in the eastern Pacific Ocean during the 1981-1987 period, extending the studies for the 1956-1980 period made by other investigators. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for the principal species of tunas and billfishes taken by that fishery. The interaction between the surface and longline fisheries is discussed. SPANISH: En este informe se presenta un repaso de la actividad pesquera de barcos palangreros japoneses en el Océano Pacifico oriental durante el periodo de 1981-1987, extendiendo los estudios del periodo de 1956-1980 realizados por otros investigadores. Se examinan las distribuciones especial y temporal de les fuerzo de pesca, la captura, la abundancia aparente, la madurez sexual, y la composición por talla de las principales especies de atunes y picudos capturadas por dicha pesquería. Se comenta la nteracción entre las pesquerías de superficie y palangrera. (PDF contains 171 pages.)

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The need to develop techniques that can make the male grow faster in many species of fish as well as the female in some other species cannot be over-emphasized. Monosex culture of the faster growing sex can increase production if the method is reliable. The use of such techniques as manual sexing, sterilisation, hybridization, gynogenesis, androgenesis polyploidy and sex-reversal can provide solutions or partial solutions to the problems associated with sexual difference, sexual maturation and unwanted reproduction

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This annotated bibliography of selected literature on Olney's three7square (Scirpus olneyi Gray )compiled basically for two reasons: 1) to assist a task force in its pursuit of an explanation for the substantial reduction in marsh acreage at the Blackwater National Wildlife Refuge in Dorchester County, Maryland, and 2) to serve as the author's foundation for the initiation of ecological research on this species as partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Botany Department of the University of Maryland. Both purposes are directly related in that the Author's research will be of use to the task force, along I with its other technical information and research results, in under-standing and possibly correcting the marshland loss problem at the Refuge. (PDF contains 100 pages)

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In this essay, three lines of evidence are developed that sturgeons in the Chesapeake Bay and elsewhere are unusually sensitive to hypoxic conditions: 1. In comparison to other fishes,sturgeons have a limited behavioral and physiological capacity to respond to hypoxia. Basal metabolism, growth, feeding rate, and survival are sensitive to changes in oxygen level, which may indicate a relatively poor ability of sturgeons to oxyregulate. 2. During summertime, temperatures >20°C amplify the effect of hypoxia on sturgeons and other fishes due to a temperature oxygen "squeeze" (Coutant 1987). In bottom waters, this interaction results in substantial reduction of habitat; in dry years, sturgeon nursery habitats in the Chesapeake Bay may be particularly reduced or even eliminated. 3. While evidence for population level effects due to hypoxia is circumstantial, there are corresponding trends between the absence of Atlantic sturgeon reproduction in estuaries like the Chesapeake Bay where summertime hypoxia predominates on a system-wide scale. Also, the recent and dramatic recovery of shortnose sturgeon in the Hudson River (4-bid increase in abundance from 1980 to1995) may have been stimulated by improvement of a large portion of the nursery habitat that was restored from hypoxia to normoxia during the period 1973-1978.

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English: This report reviews the Japanese longline fishery in the eastern Pacific Ocean during the 1993-1997 period, extending the studies for the 1956-1992 period made by other investigators. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for the principal species of tunas and billfishes taken by that fishery. Some information on the catches of sharks by the Japanese longline fishery is given. The interactions between the surface and longline fisheries are discussed. Spanish: En este informe se presenta un análisis de la actividad pesquera de buques palangreros japoneses en el Océano Pacífico oriental durante el período de 1993-1997, extendiendo los estudios del período de 1956-1992 realizados por otros investigadores. Se examinan las distribuciones espacial y temporal del esfuerzo de pesca, la captura, la abundancia aparente, la madurez sexual, y la composición por talla de las principales especies de atunes y picudos capturadas por dicha pesquería. Se presenta cierta información sobre las capturas de tiburones por la pesquería palangrera japonesa. Se describen las interacciones entre las pesquerías de superficie y palangrera.

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The Caranx hippos species complex comprises three extant species: crevalle jack (Caranx hippos) (Linnaeus, 1766) from both the western and eastern Atlantic oceans; Pacific crevalle jack (Caranx caninus) Günther, 1868 from the eastern Pacific Ocean; and longfin crevalle jack (Caranx fischeri) new species, from the eastern Atlantic, including the Mediterranean Sea and Ascension Island. Adults of all three species are superficially similar with a black blotch on the lower half of the pectoral fin, a black spot on the upper margin of opercle, one or two pairs of enlarged symphyseal canines on the lower jaw, and a similar pattern of breast squamation. Each species has a different pattern of hyperostotic bone development and anal-fin color. The two sympatric eastern Atlantic species also differ from each other in number of dorsal-and anal-fin rays, and in large adults of C. fischeri the lobes of these fins are longer and the body is deeper. Caranx hippos from opposite sides of the Atlantic are virtually indistinguishable externally but differ consistently in the expression of hyperostosis of the first dorsalfin pterygiophore. The fossil species Caranx carangopsis Steindachner 1859 appears to have been based on composite material of Trachurus sp. and a fourth species of the Caranx hippos complex. Patterns of hyperostotic bone development are compared in the nine (of 15 total) species of Caranx sensu stricto that exhibit hyperostosis.

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The commercial bottom trawl fishery for Pacific ocean shrimp, Pandalus jordani, or pink shrimp, operates mostly off the west coast of the contiguous United States. The California portion of the fishery has not been thoroughly documented or reviewed since the 1991 fishing season, despite its fluctuating more during the last 16 years (1992–2007) than at any other period in its 56-year history. We used fishery-dependent data, California Department of Fish and Game commercial landing receipts and logbook data, to analyze trends and review the California pink shrimp trawl fishery from 1992 to 2007. In particular, we focus on the most recent years of the fishery (2001–07) to highlight the gear developments and key management measures implemented in the fishery. The fishery is primarily driven by market conditions and is highly regulated by both state and Federal management agencies. Several key regulatory measures implemented during this decade have had significant effects on the fishery. For example, the requirement of a Bycatch Reduction Device on trawl nets targeting pink shrimp was approved in 2001 and has greatly reduced levels of finfish bycatch. Fishery production has declined, particularly in recent years, and may be attributed to decreased market prices, followed by reduced fishermen participation; both of which are related to changes in the processing sector and demand for the product.

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The annual catches of four small longliners operating off northeast Brazil from 1983 to 1997 were examined across different areas and locations. The total catch comprised tunas (30%), sharks (54%), billfishes (12%), and other fish species (4%). Fishing strategy and annual composition of catches showed large spatial and temporal variabilities with the dominant catches alternating among yellowfin tuna, Thunnus albacares; gray sharks, Carcharhinus spp.; and blue shark, Prionace glauca. Catches of blue and gray sharks showed a significant interaction among seamounts, with gray sharks occurring in maximum abundance around those seamounts that had relatively deep summits and low-sloping depth profiles. Results are discussed in terms of the various factors that may have influenced distribution of effort.

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Great advances have been, and are being made in our knowledge of the genetics and molecular biology (including genomics, proteomics and structural biology). Global molecular profiling technologies such as microassays using DNA or oligonucleotide chip, and protein and lipid chips are being developed. The application of such biotechnological advances are inevitable in aquaculture in the areas of improvement of aquaculture stocks where many molecular markers such as RFLPs, AFLDs and RAPD are now available for genome analysis, finger printing and genetic linkage mapping. Transgenic technology has been developed in a number of fish species and research is being pursed to produce transgenic fish carrying genes that encode antimicrobial peptides such as lysozyme thereby achieving disease resistance in fish. Also it is a short cut to achieving genetic change for fast growth and other desirable traits like early sexual maturity, temperature tolerance and feed conversion efficiency. KEYWORDS: Fish genetics, transgenesis, monoploidy, diploidy, polyploidy,gynogenesis, androgenesis, cryopreservation.

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This is the Review of discharge consents, River Irwell catchment report produced by the North West Water Authority (NWWA) in 1979. The purpose of this Report is to make recommendations for the revision of consents for discharges within the catchment of the River Irwell, downstream and including the River Medlock in Manchester. This revision has the sole objective of recognising the present effluent and river water quality - proposals for long term river water quality objectives are to be put forward in other Reports. The report identifies the existing situation regarding the legal status of effluent discharges from Authority and non-Authority owned installations within the catchment, details the determinant concentration limits included in existing discharge consents (where appropriate) and proposes the limits to be included in the reviewed consents. The reviewed consents will reflect the quality of effluent achievable by good operation of the existing plant based on 1977 effluent quality data but taking into account any improvements, extensions etc. that have been or are about to be carried out and any known further industrial and/or housing development in the works drainage area.

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Most assessments of fish stocks use some measure of the reproductive potential of a population, such as spawning biomass. However, the correlation between spawning biomass and reproductive potential is not always strong, and it likely is weakest in the tropics and subtropics, where species tend to exhibit indeterminate fecundity and release eggs in batches over a protracted spawning season. In such cases, computing annual reproductive output requires estimates of batch fecundity and the annual number of batches—the latter subject to spawning frequency and duration of spawning season. Batch fecundity is commonly measured by age (or size), but these other variables are not. Without the relevant data, the annual number of batches is assumed to be invariant across age. We reviewed the literature and found that this default assumption lacks empirical support because both spawning duration and spawning frequency generally increase with age or size. We demonstrate effects of this assumption on measures of reproductive value and spawning potential ratio, a metric commonly used to gauge stock status. Model applications showed substantial sensitivity to age dependence in the annual number of batches. If the annual number of batches increases with age but is incorrectly assumed to be constant, stock assessment models would tend to overestimate the biological reference points used for setting harvest rates. This study underscores the need to better understand the age- or size-dependent contrast in the annual number of batches, and we conclude that, for species without evidence to support invariance, the default assumption should be replaced with one that accounts for age- or size-dependence.

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The paper reviews the distribution of organic compounds in freshwater lakes and rivers. The study of dissolved organic matter in natural lakes and rivers is of importance for a variety of reasons. The organic matter may serve in part or whole as an energy source for organisms living in the aquatic environment, or it may supply them with materials essential for their nutrition.