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111.
An inherent tension exists between legal approaches to nature conservation and fisheries management in the European Union, as the former remains the remit of Member States while the latter is under the exclusive legislative jurisdiction of the European Community (EC). This tension is of particular importance when addressing the conservation of habitats or species that are under threat from fishing activities. This article examines recent developments in offshore marine conservation in the North-East Atlantic in light of the legislative developments and political frameworks that are currently evolving. By analysing the emergency closure of the Darwin Mounds area of cold-water corals and the UK pair-trawl ban, it becomes evident that the precautionary principle is a key factor in the tension between fisheries management and marine nature conservation, and is not always taken into account. 相似文献
112.
A Santa Marta JG Ferreira GC Pitcher J Lencart e Silva 《African Journal of Marine Science》2020,42(2):151-166
The carrying capacity for bivalve shellfish culture in Saldanha Bay, South Africa, was analysed through the application of the well-tested EcoWin ecological model, in order to simulate key ecosystem variables. The model was set up using: (i) oceanographic and water-quality data collected from Saldanha Bay, and (ii) culture-practice information provided by local shellfish farmers. EcoWin successfully reproduced key ecological processes, simulating an annual mean phytoplankton biomass of 7.5 µg Chl a l–1 and an annual harvested shellfish biomass of about 3 000 tonnes (t) y–1, in good agreement with reported yield. The maximum annual carrying capacity of Small Bay was estimated as 20 000 t live weight (LW) of oysters Crassostrea gigas, or alternatively 5 100 t LW of mussels Mytilus galloprovincialis, and for Big Bay as 100 000 t LW of oysters. Two production scenarios were investigated for Small Bay: a production of 4 000 t LW y–1 of mussels, and the most profitable scenario for oysters of 19 700 t LW y–1. The main conclusions of this work are: (i) in 2015–2016, both Small Bay and Big Bay were below their maximum production capacity; (ii) the current production of shellfish potentially removes 85% of the human nitrogen inputs; (iii) a maximum-production scenario in both Big Bay and Small Bay would result in phytoplankton depletion in the farmed area; (iv) increasing the production intensity in Big Bay would probably impact the existing cultures in Small Bay; and (v) the production in Small Bay could be increased, resulting in higher income for farmers. 相似文献
113.
A 120 m thick section of the Cozy Dell Formation (middle Eocene), southem California, consists of a graylaminated mudstone and a tanungraded mudstone; sandstone beds are associated with the laminated mudstone. Sedimentary structures, stratification sequences, foraminiferal
distributions, and composition indicate that the ungraded mudstone is an upper slope hemipelagic deposit, while the laminated
mudstone is an overbank deposit associated with shallow channels or gullies in which the sandstone beds were deposited. This
depositional setting may be analogous to that of the modern Mississippi River delta front. 相似文献
114.
115.
The influence of capture stress, salinity and reproductive status on zinc associated with the metallothionein-like (MT-like) proteins in the livers of three marine teleost species was investigated. In striped mullet, Mugil cephalus L., the zinc associated with the MT-like protein, as determined by gel-permeation HPLC, increased significantly from approximately 102 to 1162 nmol zinc bound/g wet wt 7 days following capture in the field, handling, transportation to the laboratory and transfer to holding tanks. Significant increases were also observed following exposure to reduced salinity for 7 days. Smaller increases were observed in cultured red drum, Sciaenops ocellatus, livers following exposure to reduced salinity and physical trauma for 7 days. Finally, there was approximately a 2·5-fold increase in the zinc associated with the MT-like protein in livers of female spotted seatrout, Cynoscion nebulosus, collected during the reproductive season compared to regressed animals. These findings emphasize the need for establishing the natural fluctuations in MT levels as well as the response to common physical environmental variables before measurement of MT can be used reliably as a biochemical indicator of environmental contamination. 相似文献
116.
Richard N. Hey Gary J. Massoth Robert C. Vrijenhoek Peter A. Rona John Lupton David A. Butterfield 《Marine Geophysical Researches》2006,27(2):137-153
Earth’s fastest present seafloor spreading occurs along the East Pacific Rise near 31°–32° S. Two of the major hydrothermal
plume areas discovered during a 1998 multidisciplinary geophysical/hydrothermal investigation of these mid-ocean ridge axes
were explored during a 1999 Alvin expedition. Both occur in recently eruptive areas where shallow collapse structures mark
the neovolcanic axis. The 31° S vent area occurs in a broad linear zone of collapses and fractures coalescing into an axial
summit trough. The 32° S vent area has been volcanically repaved by a more recent eruption, with non-linear collapses that
have not yet coalesced. Both sites occur in highly inflated areas, near local inflation peaks, which is the best segment-scale
predictor of hydrothermal activity at these superfast spreading rates (150 mm/yr). 相似文献
117.
Daniel S. Scheirer Ken C. Macdonald Donald W. Forsyth Stephen P. Miller Dawn J. Wright Marie-Hélène Cormier Charles M. Weiland 《Marine Geophysical Researches》1996,18(1):1-12
Four large-scale bathymetric maps of the Southern East Pacific Rise and its flanks between 15° S and 19° S display many of the unique features of this superfast spreading environment including abundant seamounts (the Rano Rahi Field), axial discontinuities, discontinuity migration, and abyssal hill variation. Along with a summary of the regional geology, these maps will provide a valuable reference for other sea-going programs on-and off-axis in this area, including the Mantle ELectromagnetic and Tomography (MELT) experiment. 相似文献
118.
119.
Mauffret Alain Leroy Sylvie Vila Jean-Marie Hallot Erwan Mercier de Lépinay Bernard Duncan Robert A. 《Marine Geophysical Researches》2001,22(1):17-45
Using the diving submersible survey NAUTICA we investigated the central part of the Caribbean large igneous province (CLIP) to observe and sample internal portions of this proposed oceanic plateau. Most of the samples are gabbroic and doleritic rocks; basalts are scarce. Radiometric dating by 40Ar/39Ar incremental heating experiments indicate that the intrusive rocks are Campanian in age (81–75 Ma). In some places these intrusive rocks underlie older Santonian (85–83 Ma) extrusive basaltic rocks, suggesting that the Campanian rocks represent a sill injection and an underplating episode. Results of the diving program supplemented by information from ODP and DSDP drilling sites document a 20 m.y. period (94–75 Ma) of igneous activity in the submerged portion of the Caribbean large igneous province (CLIP). In the northern part of the Beata Ridge late Campanian and/or post Campanian uplift is documented by prominent Maastrichtian (71–65 Ma) erosion and the establishment of a Paleocene-middle Eocene (65–49 Ma) carbonate platform. During and after the uplift an extensional period is indicated by seismic images and the subsidence (3 km depth) of the carbonate platform. Paleocene ages (55–56 Ma) determined on some volcanic samples are attributed to localised decompression mantle melting that accompanied the extension. We document a prolonged period of magmatic and tectonic events that do not fit with the current models of short-lived plateau formation during mantle plume initiation but shares many similarities with the constructional histories of other oceanic large igneous provinces. 相似文献
120.