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Book (series)Review of jellyfish blooms in the Mediterranean and Black Sea 2013
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No results found.Gelatinous plankton is formed by representatives of Cnidaria (true jellyfish), Ctenophora (comb jellies) and Tunicata (salps). The life cycles of gelatinous plankters are conducive to bloom events, with huge populations that are occasionally built up whenever conditions are favorable. Such events have been known since ancient times and are part of the normal functioning of the oceans. In the last decade, however, the media are reporting on an increasingly high number of gelatinous plan kton blooms. The reasons for these reports is that thousands of tourists are stung, fisheries are harmed or even impaired by jellyfish that eat fish eggs and larvae, coastal plants are stopped by gelatinous masses. The scientific literature seldom reports on these events, so time is ripe to cope with this mismatch between what is happening and what is being studied. Fisheries scientists seldom considered gelatinous plankton both in their field-work and in their computer-generated model s, aimed at managing fish populations. Jellyfish are an important cause of fish mortality since they are predators of fish eggs and larvae, furthermore they compete with fish larvae and juveniles by feeding on their crustacean food. The Black Sea case of the impact of the ctenophore Mnemiopsis leydi on the fish populations, and then on the fisheries, showed that gelatinous plankton is an important variable in fisheries science and that it cannot be overlooked. The aim of this report is to review current knowledge on gelatinous plankton in the Mediterranean and Black Sea, so as to provide a framework to include this important component of marine ecosystems in fisheries science and in the management of other human activities such as tourism and coastal development. Fact sheets on the most important gelatinous plankters of the Mediterranean and Black Seas are included as an appendix. -
Book (series)Report of the Expert Meeting on Ciguatera Poisoning
Rome, 19-23 November 2018
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No results found.Phytoplankton blooms, micro-algal blooms, toxic algae, red tides, or harmful algae, are all terms for naturally occurring phenomena that have occurred throughout recorded history. About 300 hundred species of micro algae are reported at times to form mass occurrence, so called blooms. Nearly one fourth of these species are known to produce toxins. Even non-toxic algal blooms can have devastating impacts when they lead to kills of fish and invertebrates by generating anoxic conditions. Some algal species, although non-toxic to humans, can produce exudates that can cause damage to the delicate gill tissues of fish (raphidophytes Chattonella, Heterosigma, and dinoflagellates Karenia, Karlodinium) . Aquatic animals can suffer devastating mortalities, which could lead economical and food losses, and eventually became a food security problem. Of greatest concern to humans are algal species that produce potent neurotoxins that can find their way through shellfish and fish to human consumers where they evoke a variety of gastrointestinal and neurological illnesses (paralytic shellfish poisoning (PSP), amnesic shellfish poisoning (ASP), diarrhoeic shellfish poisoning (DSP), neurotoxic shellfish poisoning (NSP), azaspiracid shellfish poisoning (AZP) and ciguatera fish poisoning (CFP)). Worldwide, ciguatoxins are estimated to cause around 50 000 cases of ciguatera fish poisoning annually; neurological effects may last for weeks or even years and one percent of these cases are fatal . Climate change and costal water over enrichment create an enabling environment for harmful algal blooms, which seem to have become more frequent, more intense and more widespread in the past decades. -
Book (stand-alone)Environmental capacity; An Approach to Marine Pollution Prevention 1986
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No results found.The aim of this Report is to provide guidelines for the assessment of the impact of potentially harmful substances released into the marine environment. The Environmental (also known as receiving, absorptive or assimilative) Capacity is defined as a property of the environment, a measurement of its ability to accommodate a particular activity or rate of an activity, such as the discharge of contaminants, without unacceptable impact. The Environmental Capacity can be apportioned for various use s. The Report proposes the use of a strategy to combat marine pollution based on this concept of Environmental Capacity. It provides the scientific rationale for the assessment of this entity, the methodology of calculation based on modelling, guidelines for its systematic application, monitoring and reassessment, and provides a number of case studies in the form of examples involving various contaminants and different geographical areas. The Report opens with a short introduction outlining the basic concepts and premisses which lie behind the acceptance of disposal of wastes in the sea. When a development is first proposed, its impact on the whole environment, together with the costs and benefits to society as a whole, must be taken into account before the plans are actually implemented. The procedure is often now known as environmental impact assessment (EIA). This wide-ranging procedure embraces far more than the scientific assessment of the impact of pollutants on the environme nt and as such lies outside the terms of reference of GESAMP. Accordingly, this Report concentrates on describing the parameters and processes which have to be taken into account in the assessment of the impact of pollutants on marine organisms, ecosystems, amenities and human health, as a consequence of any discharges to the marine environment. The methodology of assessment of Environmental Capacity as proposed in the Report, involves critical pathway analysis for both conservative and non- conservative contaminants, establishment of environmental and water quality objectives, criteria and standards. Faced with the inevitability of several sources of uncertainty in real-life conditions, a probabilistic approach is proposed as an alternative to deterministic analysis. The approach proposed is Decision Analysis, and this is exemplified by a flow diagram. The Report does not describe in detail how to gather the basic data or to carry out practical tasks such as conducting toxicity t ests or measuring water movements. To have done so would simply have duplicated material which is already available in the open literature and therefore accessible to those persons who will be brought in to advise or otherwise provide expert opinion on any project. The Report does, however, provide guidelines on how to utilize information to assess the overall impact of the activity on the marine environment. Guidance is provided on those procedures which are most likely to ensure that the activ ity can be contained within the capacity of the marine environment to receive wastes without causing unacceptable effects. The methodology of assessment of the Environmental Capacity is based on scientific research and resulting data. It is, by definition, site- and contaminant-specific. It is accomplished in stages, the preliminary assessment can be accomplished using approximations such as single-box and simple mass-balance models, and by averaging over larger time scales on the assumption o f steady-state conditions. As more data become available and transport and modification processes become better understood, more accurate values of Environmental Capacity will be obtained. These can then be used in environmentally compatible development planning and project implementation.
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