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Endangered marine species and marine protected areas in Canada
... Instead of maintaining a large stock of fishable biomass, it appears that the destructive effects of large-scale unregulated fisheries lead to lower productivity of large-bodied, high trophic-level species which are desirable in fisheries. Dramatic changes in marine ecosystem structure caused by the direct and indirect effects of fishing have damaged the fish-producing natural system [33] and endangered the existence of marine species [34]. This is clearly an example of disastrously low eco-efficiency in the production system of fisheries. ...
... Damage is also done in small-scale artisanal fisheries, such as by blast (dynamite) fishing, but in general industrial fishing is more destructive because the capacity for destructiveness is much greater. Almost all parts of the world's oceans are open to exploitation by one fishing method or another, with very little set aside as unexploited natural reserves [33][34][35]. ...
The foundation for the creation of eco-efficiency metrics for industrial impacts on biodiversity is considered. Because biodiversity is the essence of life itself, these metrics are essential for effectiveness in the theory and practice of eco-efficiency, particularly in the case of primary natural resource extraction industries such as fishing and forestry. The case of fishing is examined, with particular attention to by-catch, lost nets, and habitat damage caused by mobile fishing gears. It is appropriate to examine fishing because industrial era impacts on marine biodiversity have been severe and are driving large and deleterious changes in marine ecosystems. For discarded by-catch, it is proposed that an eco-efficient metric for the value per unit mass of discarded fish can be set to be equivalent to that of the market value of the utilized catch. In estimating the eco-efficient value of the catch, the value of the discarded fish is then subtracted from the market value of the catch. Fish killed in lost nets can be treated similarly. It is more difficult to address marine habitat damage by mobile fishing gear, which has the highest potential for ecological injury.By using the approach proposed, negative eco-efficiencies are obtained under circumstances in which the collateral damage to biodiversity exceeds the economic benefit obtained. This is a logical outcome given the long-term effects of biodiversity decline. A metric is also proposed for assessing whether avoidance of harm to biodiversity, in the form of switching fishing gear, is required. Lastly it is proposed that metrics might be developed to provide eco-efficiency credit for companies taking effective actions to improve, or actively participate in, ecosystem-based fisheries management.
Crises in fisheries around the world have made everyone realize that the health of ocean ecosystems cannot be taken for granted. In this article I discuss the science and policy of marine sanctuaries by examining the case of Atlantic Canada. By providing fishing-free sanctuaries for marine biodiversity, the richness of life in Canada's oceans be retained and healthy fisheries will also be promoted. The protection of deep-sea coral communities from mobile fishing gears is presented as an example. Marine sanctuaries can be created under the provisions of existing laws in Canada. The Oceans Act, for example, permits the creation of “marine protected areas.” The benefits of marine protected areas are discussed, and plans for developing systems of marine protected areas are outlined. Peer-reviewed article accepted for publication on 17 February 2002.
Approximately 22% of the waters of the Merritt Island National Wildlife Refuge, which encompasses the Kennedy Space Center, Florida, have been closed to public access and fishing since 1962. These closed areas offer an opportunity to test the effectiveness of “no-take” sanctuaries by analyzing two replicated estuarine areas. Areas open and closed to fishing were sampled from Nov 1986 to Jan 1990 with 653 random trammel-net sets, each enclosing 3,721 m. Samples from no-fishing areas had significantly (P < 0.05) greater abundance and larger fishes than fished areas. Relative abundance (standardized catch per unit effort, CPUE) in protected areas (6.4 fish/set) was 2.6 times greater than in the fished areas (2.4 fish/set) for total game fish, 2.4 times greater for spotted seatrout Cynoscion nebulosus, 6.3 times greater for red drum Sciaenops ocellatus, 12.8 times greater for black drum Pogonias cromis, 5.3 times greater for common snook Centropomus undecimalis, and 2.6 times greater for striped mullet Mugil cephalus. Fishing had the primary effect on CPUE, independent of habitat and other environmental factors. Salinity and depth were important secondary factors affecting CPUE, followed by season or month, and temperature. The importance of specific factors varied with each species. Median and maximum size of red drum, spotted seatrout, black drum, and striped mullet were also significantly greater in the unfished areas. More and larger fish of spawning age were observed in the unfished areas for red drum, spotted seatrout, and black drum. Tagging studies documented export of important sport fish from protected areas to fished areas.
In this paper we examine the summer distribution of three species of small odontocetes in the highly productive waters in and near the Gully, a submarine canyon on the edge of the Scotian Shelf. Atlantic white-sided dolphins (Lagenorhynchus acutus) and common dolphins (Delphinus delphis) were not randomly distributed with respect to depth, sea-floor relief, month of sighting, or sea-surface temperature. Long-finned pilot whales (Globicephala melas) were not randomly distributed with respect to month or sea-surface temperature. These species used the Gully slightly differently, although there was overlap. White-sided dolphins were seen only in the core of the canyon, but were sighted at all temperatures, depths, and sea-floor reliefs and throughout the summer field season. Common dolphins had a modest range throughout the deeper waters and were not seen in the summer before July, when the water warms. Pilot whales ranged widely over the study area, preferring areas with fairly flat relief and were more common later in the summer, when the waters were warmer. It appears that white-sided and common dolphins partition the Gully temporally but not geographically.
Improved management approaches are needed to reduce the rate at which humans are depleting exploited marine populations and degrading marine ecosystems. Networks of no-take marine reserves are promising management tools because of their potential to (1) protect coastal ecosystem structure and functioning, (2) benefit exploited populations and fisheries, (3) improve scientific understanding of marine ecosystems, and (4) provide enriched opportunities for non-extractive human activities. By protecting marine ecosystems and their populations, no-take reserve networks can reduce risk by providing important insurance for fishery managers against overexploitation of individual populations. Replicated reserves also foster strong scientific testing of fishery and conservation management strategies. Reserve networks will require social acceptance, adequate enforcement, and effective scientific evaluation to be successful. Processes for reserve establishment should accommodate adaptive management so boundaries and regulations can be modified to enhance performance. However, even well-designed reserve networks will require continued conservation efforts outside reserve boundaries to be effective. Establishing networks of no-take reserves is a process-oriented, precautionary management strategy that protects functional attributes of marine ecosystems. As an addition to fishery management practices and other conservation efforts, no-take reserve networks may improve the status of exploited populations while conserving marine resources for future generations.
Coastal zones are usually managed with two main objectives: (1) conservation/maintenance of biodiversity and intrinsic ecosystem services and (2) maintenance of sustainable fisheries. The management needs that can be met with marine protected areas fall into corresponding categories. First, fully protected (that is, no-take) reserves—parks—offer benchmarks and protect ecosystem integrity while encouraging research, education, and aesthetic appreciation of nature. Second, by allowing focused local control of human impacts, marine protected areas can be used to focus more intense local management designed to increase yield and allow research to help define sustainability and protect against uncertainty by using carefully managed fisheries as a research tool. We have been gambling with the future by establishing a poor balance between short-term profit and long-term risks. The absence of meaningful, fully protected reserves has produced a situation in which there are virtually no areas north of the Antarctic in the world's oceans that have exploitable resources where scientists can study natural marine systems. In most areas the higher-order predators and many other important species have been virtually eliminated; many benthic habitats have been much changed by fishing activities. Without solid data documenting changes through time, the relative merits of various causes and effects that operate in complex ecological systems can always be argued. Without natural systems important questions cannot be studied—for example, how the ecosystem roles of various species can be assessed, how they can be managed in a sustainable manner, and how we can evaluate resilience or relative rates of recovery. Networks of fully-protected reserves could facilitate research into such questions, contribute to the recovery of many coastal systems, and enable society to enrich its existence by observing species that should be part of its heritage (Murray et al., 1999). The use of marine protected areas as fishing refugia has met strong resistance by fishers and many managers, and it is misunderstood by many conservation biologists because different proponents have different, usually simplistic, visions. It is important to spell out the objectives of each proposed example. Our essential habitat perspective emphasizes that each situation depends on specific life-history parameters and emphasizes critical thresholds in population dynamics, including density and behavior for fertilization, transport processes, settlement, survivorship, and growth to maturity. These are extremely difficult problems, and we cannot expect simplistic solutions to be effective. The only basis for optimism is that most of the seriously affected species are not yet extinct, and we still have a little time to establish permanent fully protected reserves to allow mankind to appreciate its rich but much depleted biological heritage. At least in some systems recovery can be measured over short time scales (<10 yrs), whereas others are much slower. Society as a whole is the ultimate stakeholder, not only the commercial and sports fishing industries that so dominate the public arena. Society will have to play a more active role if these species and habitats are to be saved.
An indigenous population of 450-500 beluga whales (Delphinapterus leucas) inhabiting the St. Lawrence Estuary has been exposed chronically for more than 50 years to a complex mixture of industrial pollutants including organochlorinated compounds (OC), polycyclic aromatic hydrocarbons (PAH) and heavy metals. From 1983 to 1990, we have necropsied 45 well preserved carcasses out of a total of 120 beluga whales reported dead over this period. Of these 45 animals, nine were affected by 10 malignant neoplasms. Fifteen animals (33%) were affected by pneumonia. Milk production was compromised in eight of 17 mature females (41%), by inflammatory changes (seven animals) and cancer (one animal) which affected the mammary glands. Opportunistic bacteria were found in pure culture, and/or in significant amounts in at least two organs in 20 belugas (44%). The concentrations of both total PCBs and highly chlorinated PCB congeners were much higher in St. Lawrence animals than in Arctic beluga whales. OC-induced immunosuppression has been repeatedly demonstrated in a wide variety of animal species. Therefore, it is probable that the immune functions of St. Lawrence beluga whales are impaired. Benzo[a]pyrene adducts were detected in 10 of the 11 St. Lawrence beluga whales of which tissues (six livers, 10/11 brains) were analyzed by a method based on HPLC. No such adducts were found in four Arctic animals. Since benzo[alpha]pyrene is one of the most potent chemical carcinogens known to man, these compounds might be responsible for some of the cancers observed in that population. Overall, our findings contrast vividly with those of others who found that cancers are exceedingly rare in free-ranging odontocete populations and that the major causes for mortalities in these populations are bacteria, parasites, and trauma.
The mean trophic level of the species groups reported in Food and Agricultural Organization global fisheries statistics declined
from 1950 to 1994. This reflects a gradual transition in landings from long-lived, high trophic level, piscivorous bottom
fish toward short-lived, low trophic level invertebrates and planktivorous pelagic fish. This effect, also found to be occurring
in inland fisheries, is most pronounced in the Northern Hemisphere. Fishing down food webs (that is, at lower trophic levels)
leads at first to increasing catches, then to a phase transition associated with stagnating or declining catches. These results
indicate that present exploitation patterns are unsustainable.
Jean Baptiste de Lamarck and Thomas Huxley, two of the foremost thinkers of the 18th and 19th centuries, believed that humanity could not cause the extinction of marine species. Their opinions reflected a widespread belief that the seas were an inexhaustible source of food and wealth of which people could barely use a fraction. Such views were given weight by the abundant fisheries of the time. Additionally, the incredible fecundity and wide distributions of marine fishes, combined with limited exploitation, provided ample justification for optimism. The ideas of Huxley and Lamarck persist to this day, despite a sea change in the scale and depth of our influence on the oceans. Marine species could be at a far greater risk of extinction than we have assumed.
Marine protected areas (MPAs) have an important role in marine conserva tion programmes around the world. Although most have been established relatively recently when compared with protected areas on land, there is considerable expertise on their identification, setting up and management. Some techniques have been adapted from those used on land. Others are novel, and unique to marine conservation. The chapters in this book give an insight into this fast developing field where experiment and innovation work alongside techniques which have been tried and tested. The guiding princi ples behind key stages in the setting up and management of MP As are described, and case studies illustrate how they have worked. While it is most encouraging to read about the successes, the case studies also point to difficulties which have been encountered. Not all of the examples are new or recent but, together, they illustrate what is happening in this field.
Twenty five blocks of Lophelia pertusa weighing a total of 18.5 kg were studied. Associated with this substrate were 4 626 individuals belonging to 256 species. An additional 42 species were identified from loose coral rubble. Of the 298 species found, 97 are recorded for the first time from the area around the Faroes. Most individuals were found in dead coral blocks from the inner parts of the bank or colony, but a few species were found close to the terminal branches of live coral blocks. The associated fauna of this branching deep-water coral was as rich and diverse as that of hermatypic branching species of coral. Some physical features of the coral as a substrate were measured. Large blocks of live coral harbour a more diverse fauna than do smaller ones. In contrast, on dead coral blocks the number of species and individuals had no simple correlation to block size, indicating the importance of other factors such as random colonization and length of time the substrate has been inhabited. Of the 20 most abundant species only four showed a correlation between the number of individuals and coral weight. Ecological aspects of the associated fauna are discussed and the results are compared with studies from associations on hermatypic corals. Comparing with studies of Lophelia banks from Norway and the Bay of Biscay we find very few overlaps in the associated species. A highly diverse and rich but facultative fauna is associated with the Lophelia banks.
A population of approximately 230 Northern Bottlenose Whales, Hyperoodon ampullatus, uses the Gully, a prominent submarine canyon on the edge of the Scotian Shelf. These animals use the Gully throughout the year. Approximately 57% of the population reside in a 20 km X 8 km core area at the entrance of the canyon at any time. The Gully animals seem to be largely or totally distinct from the population seen off northern Labrador: they are smaller and appear to breed at a different time of year. Threats to the population include commercial shipping, fishing and oil and gas developments. One oil and gas discretely of commercial interest, the Primrose Field, lies about 5 km from the core area of this population. The population is vulnerable because of its small size, location at the extreme southern limit of the species' range, and year-round dependence on a small and unique sea area. It is threatened by plans for the development of the oil and gas fields close to the Gully.
Sea Otters (Enhydra lutris) ranged historically across the north Pacific from the central Pacific coast of Baja California, to northern Japan. An intensive fur hunt in the 18th and 19th centuries extirpated the Sea Otter from much of its range. The species was protected in 1911, and now occupies approximately half of its historic range. Presently, the worldwide population of Sea Otters is thought to be about 150 000 animals. The British Columbia Sea Otter population, originating from 89 animals reintroduced to Vancouver Island from 1969 to 1972, has increased at a finite rate of 18.6% per year, a rate similar to reintroduced populations in Washington and southeast Alaska. In 1995, a minimum of 1522 Sea Otters were found in British Columbia. Most of these animals occurred off Vancouver Island, but at least 135 Sea Otters were found near Goose Island, 125 km north of Vancouver Island. The origin of this latter group is uncertain. Sea Otters are presently classed as threatened in British Columbia and are protected under Federal and Provincial regulations.
Northern bottlenose whale is a deep-diving, medium-sized teuthophage endemic in the North Atlantic Ocean. Its known distribution is centered in areas with cold, deep water along and seaward of the edge of the continental shelf. Migratory movements are poorly documented, as are stock relations among the animals found in apparently disjunct centers of spring and summer abundance. In the W North Atlantic, bottlenose whales are present during much of the year in The Gully near Sable Island (Nova Scotia) and in the Labrador Sea. The northern bottlenose whale remains widely distributed and locally abundant in some areas. It has been protected from commercial whaling since 1977 and is no longer hunted regularly on a large scale anywhere in its range. The species does not appear to be threatened or endangered at present. -from Authors
Increasing attention is being paid the world over for affording protection to, and conservation of marine mammals. They are the most vulnerable group of sea animals, excepting the sea turtles. Public awareness needs to be created to remove the prejudices towards marine mammals. There is need for their protectior in modem times through regulations, up-dating existing legislations, collec-tion of scientific data, establishment of sanctuaries, extending of financial and other support and inter-governmental and regional cooperation. The status of the dugong in the seas around India is cited as a case in particular for conservation and management through appropriate regulatory mea-sures, intensified scientific study, establishment of sanctuaries in situ and regional cooperation.
Summary of the sea otter in relation to the eastern Pacific Ocean, including physical characteristics, habitat requirements, general behavior, food and feeding behavior, distribution and numbers, reproduction, limiting factors, and behavior in captivity.
The action taken in December 1970 by the U.S. Department of the Interior in placing eight species of large whales on an endangered species list has emphasized the need for up-to-date information on their populations. The present paper summarizes a large number of observations on one of these eight species and suggests that the bowhead population of Canada is recovering well after intensive exploitation up till the early years of the present century, though it may amount to only a small percentage of the population present before commercial whaling began.
This is an analysis of the complex issues that relate to the conservation of whales, dolphins and other cetaceans. Experts from both the scientific and conservation communities provide contributions that, firstly, review the threats that cetaceans are faced with in a modern world - some of which are now well understood - and secondly, critically assess responses which have been made to these threats. The chapters reflect the diversity of opinion that exists in this field. Topics covered include: pollution issues; habitat degradation; noise; global change; disease; and the special case of the river dolphins. Apposite authors also consider the international agreements that affect cetaceans (including the International Whaling Commission) and the role of sanctuaries and action plans.
The first marine reserve in New Zealand was established in 1977 for scientific reasons. The rules were simple but strict -no fishing, no removals and no disturbance -but everyone welcome to come and study or just appreciate the more natural conditions. The value of having "no-take" areas in the sea has, since then, become widely appreciated by recreational groups, schools, tourists, scientists, and fisheries interests. The list of potential benefits has steadily expanded, and evidence for their existence has accumulated. Specific benefits are commonly perceived, but the possibility of wider benefits, resulting from a network of ecologically-representative marine reserves, is beginning to receive serious consideration. As a result, more marine reserves are being proposed at an increasing rate. By early 1994, eleven reserves had been established, five more await final decision and 20 further proposals are in various stages of public discussion. All political parties in N.Z. now endorse "no take" marine reserves in principle, and some are proposing "10% of all marine habitats by the year 2000". The lessons are simple but surprising. Management of marine resource exploitation and its problems is necessary but not sufficient. An independent and additional system that ignores the "problems" (of controlling fisheries, waste disposal, habitat destruction, etc.) and concentrates on providing unexploited areas in the sea is scientifically essential (for observational and experimental controls); economically sensible (for insurance and sustainability); and socially-acceptable in a democracy (for a wide variety of positive reasons, including conservation principles, education and recreation).
The Gully, the largest submarine canyon off the coast of East Canada, is currently under consideration as a marine conservation area, primarily because of the increasing interset in oil and gas production on the Scotian Shelf. Cetaceans, as a guild of abundant, large organisms that are relatively sensitive to such threats, provide a reliable means to determine the boundaries for a conservation area in this region. We compared the abundance of cetaceans between the Gully and the other parts of the Scotian Shelf and Slope and found that abundance was higher in the Gully. We also assessed cetacean distribution and relative abundance within the Gully relative to search effort for several effort for several apatial and temporal parameters: depth, slope, sea surface temperature, and month. Distribution within the Gully was most strongly correlated with depth, but was also significantly correlated with sea surface temperature and month. Five of the 11 cetacean species commonly found in the Gully, and all those for which the Gully formed significant habitat on the Scotian Shelf, were concentrated in the deep (200-2000 m) mouth of the canyon. We suggest that a year-round marine protected area is necessary for the Gully. A core protection zone should be defined in the Gully based on depth and bounded by the 200-m isobath. A buffer zone around the core zone should be defined to provide protection from activities with further-reaching effects, such as noise, dredging, and chemical pollution.
Coral reefs have reconstituted themselves after previous large sea‐level variations, and climate changes. For the past 6000 years of unusually stable sea‐level, reefs have grown without serious interruptions. During recent decades, however, new stresses threaten localized devastation of many reefs. A new period of global climate change is occurring, stimulated by anthropogenic increases in greenhouse gases. Coral reefs will cope well with predicted sea‐level rises of 4.5 cm per decade, but reef islands will not. Higher sea levels will provide corals with greater room for growth across reef flats, but there are no foreseeable mechanisms for reef island growth to keep pace with sea‐level rise, therefore many low islands may ultimately become uninhabitable.
Climate change will introduce localized variations in weather patterns, but changes to individual reefs cannot be predicted. Reefs on average should cope well with regional climate change, as they have coped with similar previous fluctuations. Air temperature increases of 0.2–0.3 °C/decade will induce slower increases in sea‐surface temperatures, which may cause localized, or regional increases in coral bleaching. Changes in rainfall will impact on reefs near land masses. Likewise, increased storms and variations in El Nino Southern Oscillation (ENSO) may stress some reefs, but not others.
The greatest impact of climate change will be a synergistic enhancement of direct anthropogenic stresses (excessive sediment and pollution from the land; over‐fishing, especially via destructive methods; mining of coral rock and sand; and engineering modifications), which currently cause most damage to coral reefs. Many of the world's reefs have been degraded and more will be damaged as anthropogenic impacts increase under the ‘demophoric’ increases in population (demos) and economic (phoric) activity. This biotic and habitat loss will result in severe economic and social losses. Reefs, however, have considerable recovery powers and losses can be minimized by effective management of direct human impacts and reducing indirect threats of global climate change.
Bottom trawling and use of other mobile fishing gear have effects on the seabed that resemble forest clearcutting, a terrestrial disturbance recognized as a major threat to biological diversity and economic sustainability. Structures in marine benthic communities are generally much smaller than those in forests, but structural complexity is no less important to their biodiversity. Use of mobile fishing gear crushes, buries, and exposes marine animals and structures on and in the substratum, sharply reducing structural diversity. Its severity is roughly comparable to other natural and anthropogenic marine disturbances. It also alters biogeochemical cycles, perhaps even globally. Recovery after disturbance is often slow because recruitment is patchy and growth to maturity takes years, decades, or more for some structure-forming species. Trawling and dredging are especially problematic where the return interval—the time from one dredging or trawling event to the next—is shorter than the time it takes for the ecosystem to recover; extensive areas can be trawled 100–700% per year or more. The effects of mobile fishing gear on biodiversity are most severe where natural disturbance is least prevalent, particularly on the outer continental shelf and slope, where storm-wave damage is negligible and biological processes, including growth, tend to be slow. Recent advances in fishing technology (e.g., rockhopper gear, global positioning systems, fish finders) have all but eliminated what were de facto refuges from trawling. The frequency of trawling (in percentage of the continental shelf trawled per year) is orders of magnitude higher than other severe seabed disturbances, annually covering an area equivalent to perhaps half of the world’s continental shelf, or 150 times the land area that is clearcut yearly. Mobile fishing gear can have large and long-lasting effects on benthic communities, including young stages of commercially important fishes, although some species benefit when structural complexity is reduced. These findings are crucial for implementation of “Essential Fish Habitat” provisions of the U.S. Magnuson-Stevens Fishery Conservation and Management Act which aim to protect nursery and feeding habitat for commercial fishes. Using a precautionary approach to management, modifying fishing methods, and creating refuges free of mobile fishing gear are ways to reduce effects on biological diversity and commercial fish habitat.
Perturbaciones del Lecho Marino por Artes de Pesca Móbiles: Una Comparación con la Tala Forestals
Los arrastres de fondo y el uso de otras artes de pesca móviles tienen efectos en el lecho marino que se asemejan a la tala total de bosques, que es a su vez una pertubación terrestre reconocida como una de las mayores amenazas a la diversidad biológica y la sustentabilidad económica. Las estructuras en comunidades marinas bénticas son generalmente mucho más pequeñas que aquellas en los bosques, pero la complejidad estructural no es menos importante que la biodiversidad. El uso de artes de pesca móviles quiebra, sepulta y expone animales marinos y estructuras sobre y en el substrato, reduciendo marcadamente la diversidad estructural. Su severidad es burdamente comparable con otras perturbaciones marinas de orden natural o antropogénico. Tambien altera los ciclos biogeoquímicos, de hecho a nivel mundial. La recuperación después de una pertubación es frecuentemente lenta debido a que el reclutamiento es por parches y el crecimiento para alcanzar la madurez toma años, décadas o aún más para algunas especies que forman estructuras. Los arrastres de fondo y dragados son especialmente problemáticos donde el intervalo de retorno (tiempo entre un evento de dragado o arrastre y otro) es más corto que el tiempo que toma a un ecosistema recuperarse;árears extensas son arrastradas entre un 100 y 700% por año o mas. Los efectos de las artes de pesca móviles en la biodiversidad son más severos cuando las perturbaciones naturales son menos prevalentes, particularmente en las afueras de la plataforma continental y la pendiente, donde el daño del oleaje por tormentas es negligible y los procesos biológicos (incluyendo crecimiento) tienden a ser lentos. Recientes avances en tecnología pesquera (e.g., sistemas de posicionamiento global, detectores de peces) aparentemente tienen todo, pero eliminan lo que de facto fueran refugios contra arrastres. La frecuencia de los arrastres (en porcentaje de la plataforma continental arrastrada por año) es órdenes de magnitud mayor que otras perturbaciones severas al lecho marino, anualmente la cobertura de área es equivalente quizá a la mitad de la plataforma continental marina, o 150 veces el área de tierra que es talada anualmente. Las artes de pesca móviles pueden tener impactos grandes y de larga duración en las comunidades bentónicas, incluyendo estadios jóvenes de peces de importancia comercial, aunque algunas especies se benefician cuando la complejidad estructural es reducida. Estos descubrimientos son cruciales para la implementación de el “hábitat esencial para peces” del Acta de Conservación y Manejo de Pesquerias Magnuson-Stevens de los Estados Unidos y que pretende establecer hábitats de reproducción y alimentación para peces comerciales. El uso de una aproximación precautoria de manejo, la modificación de métodos de pesca y la creación de refugios libres de artes de pesca móviles son formas para reducir los efectos en la diversidad biológica y el hábitat para peces comerciales.
The most serious danger to dolphins and porpoises around the world is the
threat from various forms of gill-net fishing. One potential way to reduce
the number of deaths of marine mammals is the use of active acoustic alarms
to warn animals about the presence of nets1. Until now, acoustic
alarms have not been tested in field experiments with sufficient statistical
power2. Here we describe a field experiment showing that acoustic
alarms are effective at reducing the number of deaths of harbour porpoises
(Phocoena phocoena) in sink gill-nets.
Are extinctions of marine vertebrates as rare and unlikely as current data indicate? Long-term research surveys on the continental
shelf between the Grand Banks of Newfoundland and southern New England reveal that one of the largest skates in the northwest
Atlantic, the barndoor skate (Raja laevis), is close to extinction. Forty-five years ago, research surveys on St. Pierre Bank (off southern Newfoundland) recorded
barndoor skates in 10% of their tows; in the last 20 years, none has been caught, and this pattern of decline is similar throughout
the range of the species.
Marine Protected Area and Ocean Conervation
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Review of the status of anadromous Atlantic Salmon (Salmo salar) under the U
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The U.S. National Marine Sanctuary Program and its role in preserving sustainable fisheries
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Marine Protected Areas as a Tool for Cetacean Conservation
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Environmental effects of marine fishing. Aquatic Conservation: Marine and Freshwater Ecosystems
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Creating the Saguenay Marine Park -a case study
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