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1.
The distribution of various tuna species in the Pacific Ocean is bounded by the 20°C isotherm while their migrations are influenced by the major current systems and other oceanographic parameters which are here described. Tuna fisheries are important for the island nations of the tropical Pacific with Japan, the USA, Korea, Taiwan and the Philippines prominently engaged in them. The fishery relies on longline, bait-dependent pole and line and purse seining techniques. The various tuna species are among the highest priced fishery commodities vigorously entering international trade in the frozen state or canned. However, with 200 nautical mile extended economic zones now being customary international law, new patterns of resource ownership and management needs have arisen that call for enhanced international cooperation in fisheries research and in surveillance and enforcement; a discussion of possible patterns for such cooperation terminates this article.This article is a contribution of the Oceans Project of the East-West-Center, Honolulu, Hawaii 相似文献
2.
A problem of locating and comprehensively investigating ocean areas that exercise a significant influence over the migration
dynamics of fishing ranks among important problems of fisheries oceanology. Among all the environment factors affecting various
fishery situations, factors should be chosen that are constantly logged on large water areas for a long time comparable with
fishery observation time. As described in a number of works, the most suitable information for these purposes is data on the
distribution of surface temperature fields.
The problem of locating discriminative areas can then be stated as follows. For a particular fishery situation (e.g., for
the period of maximum catch in fishing season), temperature values or thermostructural features should be singled out that
are suitable to define the situation, using hydrological charts of surface temperature fields. Correlating the feature with
the areas where they were observed, we will obtain discriminative areas.
The important problem is then to develop techniques and means for algorithmically identifying areas. This relates to a vast
volume of information and complex structure.
Logical-mathematical models of locating discriminative areas are being developed at the Pacific Oceanological Institute for
some years. These models are to be for forecasting fishery situations in the NW Pacific. Techniques for representing isotherm
fields in a computer have been developed. Formal operations of comparing the fields have been proposed which aid in distinguishing
significant differences in their structure. A software for analyzing isotherm fields has been developed based on threshold
logic models.
This approach allows one not only to identify discriminative areas for relatively stable fishery situations but also to trace
their dynamics. This has been achieved due to multiple-alternative computations and the presentations of data obtained in
the form suitable for their interpretation. Some components of proposed models have been used in the system of short-term
forecasting saira and sardine fishery in the South-Kuril area. 相似文献
3.
This paper attempts to overcome the dichotomy between the broadly different and largely separate fisheries science and management (FSM) and ecosystem science and management (ESM) knowledge systems that characterise the international literature and are found in fisheries management practice in different countries. The paper argues that the construction of a heuristic we term the fisheries problematic, around issues and contexts, reveals the breadth of international fisheries management concerns and the variety of contexts in which these concerns are being faced. Adopting a political economy informed nature-society approach the paper considers ecological and socio-economic processes in their institutional settings in an attempt to shift from the either/or arguments around fish or ecosystems found in the FSM or ESM literatures to investigation that is grounded in understandings of the historically and geographically specific trajectories of fisheries related interactions and understandings of how knowledge about the trajectories and their interactions is fashioned. Drawing on recent conceptual innovations in the field, the paper develops a matrix-centred approach to explore ecological, industry, community and policy domains in New Zealand’s Quota Management System (QMS) and Individual Transferable Quota (ITQ) fisheries management regime. The extended framework prioritises scrutiny of the interaction amongst the four domains, as a strategy to help develop institutional frameworks that facilitate behaviours that are societally inclusive. The paper offers three conclusions. First, the landscape of New Zealand fisheries issues is very much a product of the contingent interaction of the QMS, a management regime designed around the principles of a FSM approach and laid down in a neo-liberal political environment and Maori aspirations encompassing the fisheries sector. Second, the conceptual mapping of FSM and ESM perspectives over New Zealand’s fisheries management experience highlights that a number of management issues have been down played by the commitment to FSM, a situation that has led to on-going tensions between commercial, recreational and customary stakeholders regarding fisheries management. Put another way, there is more to running a sustainable fishery (as defined in the Fisheries Act 1996) than QMS and other tools and dialogue about the development of these should be a priority. Third and more generally, improved dialogue on fisheries questions is likely to be most expeditiously advanced by studies that explicitly conceptualise and contextualise ecological and socio-economic processes and their institutional arrangements. 相似文献
4.
Atlantic croaker is one of the most abundant demersal fish in Chesapeake Bay. Until recently, when substantial declines in
abundance have occurred, high biomass supported elevated fisheries landings. Therefore, study of the diet of Atlantic croaker
is important to understand its own dynamics and its role in the Chesapeake Bay ecosystem. Patterns in the diet of croaker
varied annually, seasonally, and spatially, but were not strongly correlated with any measured environmental variables. Although
the majority of the diet of croaker consisted of polychaetes and other benthic items, about 20% of the croaker diet by weight
consisted of anchovy and other fishes. Croaker consumption of anchovy is likely a result of crepuscular feeding that has not
been captured in previous studies that sampled during the day and with bottom trawls. Thus, croaker influences both the benthic
and pelagic components of the Chesapeake Bay food web and incorporating such diel patterns in diet may increase the reliability
of fishery ecosystem models. 相似文献
5.
《Geoforum》2016
Eco-certifications have become an important site of power struggles in commodity sectors such as forestry, fisheries, aquaculture, palm oil, and soy. In each, multiple eco-certification initiatives have been developed and resisted through interactions among non-governmental organizations, governments, and commercial actors. This paper contributes to understanding how power is embodied in certifications by exploring how territoriality manifests in the international struggle over defining what products are ‘sustainable’ and which producers will have access to markets that require ‘sustainable’ products. Focusing on the wild capture fisheries sector in which the non-governmental Marine Stewardship Council (MSC) administers the preeminent eco-certification initiative, we explore the emergence of new fisheries eco-certification initiatives in Japan, Iceland, Alaska, Canada, and the US that insist there is no transnational monopoly on judgments over fisheries sustainability. We argue that these new eco-certifications attempt to defend and embed territorial social and regulatory relations of production within the contested domain of transnational sustainability governance. The initiatives accommodate both the territorially embedded material interests, institutions, and discursive strategies of producers (and their state supporting agencies) and transnationally embedded governance norms for assessing and communicating sustainability. They also counter the globally applicable institutions of the MSC in favor of making space for state and non-state actors to contend with demands for sustainability in the global seafood market by combining place-specific attributes with transnational governance norms. 相似文献
6.
S.E. Lluch-Cota M. Tripp-Valdez D.B. Lluch-Cota J.J. Bautista-Romero D. Lluch-Belda J. Verbesselt H. Herrera-Cervantes 《Atmósfera》2013,26(4):537-546
Changes in global mean sea surface temperature may have potential negative implications for natural and socioeconomic systems; however, measurements to predict trends in different regions have been limited and sometimes contradictory. In this study, an assessment of sea surface temperature change signals in the seas off Mexico is presented and compared to other regions and the world ocean, and to selected basin scale climatic indices of the North Pacific, the Atlantic and the tropical Pacific variability. We identified eight regions with different exposure to climate variability: In the Pacific, the west coast of the Baja California peninsula with mostly no trend, the Gulf of California with a modest cooling trend during the last 20 to 25 years, the oceanic area with the most intense recent cooling trend, the southern part showing an intense warming trend, and a band of no trend setting the boundary between North-Pacific and tropical-Pacific variability patterns; in the Atlantic, the northeast Gulf of Mexico shows cooling, while the western Gulf of Mexico and the Caribbean have been warming for more than three decades. Potential interactions with fisheries and coastal sensitive ecosystems are discussed. 相似文献
7.
The Atlantic horsehoe crab,Limulus polyphemus, is harvested by the biomedical industry for Limulus Amoebocyte Lysate (LAL) a blood compound used to detect endotoxins,
for scientific research on vision, and as bait for the eel and conch fisheries. They are also subject to sources of natural
mortality such as consumption of eggs by shorebirds and stranding. Recently there has been growing concern over possible declines
inLimulus populations along the east coast of the United States. We have used stage-structured matrix modeling to improve our understanding
ofLimulus population dynamics in three Cape Cod estuaries (Stage Harbor, Pleasant Bay, and Barnstable Harbor) with differing harvest
pressures. The results suggest that a low level of harvest is sustainable, particularly if timing and size-specificity of
the harvest are taken into consideration. The model also suggests that efforts should be made to avoid harvesting crabs prior
to sexual maturity, as the population growth rate is more sensitive to changes in survival rate of older juveniles than of
other stages. The information the model provides could assist local and regional fisheries managers in establishing appropriate
regulations for the horseshoe crab fishery. 相似文献
8.
Akhtar Husain Siddiqi 《GeoJournal》1992,26(3):395-411
This study assesses the condition of the fishing industry in Pakistan. It briefly reviews the ecological environment of Pakistan's
fisheries and describes recent developments in technology and their impact on the catch. The factors contributing to growth
include government efforts, fleet expansion and development of export markets. This study also points out the difficulties
in arriving at a satisfactory management policy for the regulation of the industry. Development strategies seek rational,
efficient exploitation of marine resources for the broad goals of national development. Consequently, policy makers' fisheries
management concepts and techniques are generally less effective in addressing the need of the coastal communities. The conclusion
is that fisheries development effort need balanced resource management, serving as an instrument for regional development
while taking into account the traditional resource use rights of small-scale fishermen. 相似文献
9.
南极海冰与温度变化关系的统计分析(英) 总被引：3，自引：0，他引：3
Temporal-spatial characteristics of Antarctic surface air temperature and sea ice variations have been statistically analyzed. Results show that, during the last 30 years there was an obvious warming trend in Antarctica, but there exists substantial difference in different sectors and different period. The most significant warming trend occurred in the Antarctic Peninsula, about 2-3 times greater than that in the whole east Antarctica. In recent 20 years the correlation between Antarctic mean temperature and mean sea ice area is low and insignificant, but its linear trends are found to be opposite related in each sector, that is, sea ice extent reductions when temperatures are high. The different climate sectors defined by cluster analysis clearly show a close relationship between two parameters on the inter-seasonal time scale. The most sensitive correlation sectors found are from south Atlantic to southwest Pacific ocean. 相似文献
10.
The continental margin orogenic systems of the western Americas are enormous features that formed along the Pacific margins of the North and South American plates during late Mesozoic through Cenozoic time. There has been considerable debate concerning their origin, and they are often compared with intra-oceanic fringing arc-trench systems more typical of the Australasian margins of the Pacific Ocean, in that both involve the subduction of oceanic lithosphere, often with similar convergent relative motion vectors. The onset of orogenesis in the two Cordilleras, as shown in reversal of sedimentary polarity from sources generally on the continent to sources along the Pacific margin, seems to date from shortly after emplacement of the oldest oceanic crust in that part of the Atlantic Ocaen east of each continent — i.e., about 170 Ma, or Middle Jurassic, in the case of the Central Atlantic, and about 135 to 100 Ma, or Early to mid-Cretaceous, in the case of the South Atlantic. These ages also seem to mark the onset of westward motion of the two continents over the Pacific Ocean basin and subsequent crustal thickening and uplift, with development of thrust belts, foreland basins, and foredeeps. Prior to this prolonged westward drift, both margins had been convergent for at least several hundred million years, but no massive mountain building had taken place. Instead, the margins were tectonically “neutral”, with typically submarine fringing arc-trench systems or shallow marine to continental margin arcs which stood “outboard” of shallow marine platformal shelves or basins whose main sedimentary polarity was from the continent. Although accretion of “suspect” terranes, high rates of convergence, and age of subducting lithosphere all may have influenced particularly local tectonic response and/or phases of orogenic activity in the two chains, the absolute motion of the two continental margins over the Pacific Ocean basin is considered to have been the dominant factor in Cordilleran tectonic evolution. 相似文献
11.
西太平洋——我国深海科学研究的优先战略选区 总被引：2，自引：0，他引：2
西太平洋是我国实施由浅海向深海发展战略的必经之地.从国家需求的角度来看,西太平洋海底资源丰富、海洋环境复杂,是维护国家权益的焦点、保障国防安全的屏障;从科学前沿的角度来看,西太平洋发育有独特的沟弧盆构造体系和弧后盆地热液系统,存有海底板块运动的遗迹和众多海山生态系统,更是"大洋传送带"冷暖水系的转换区.科学有序地进入西... 相似文献
12.
The North Sea: co-ordinated sea use management 总被引：1，自引：0，他引：1
The purpose of this paper is to consider the sea use management in the North Sea with reference to the re-structuring of the global and European economies; the sectoral activities including maritime transport and strategic issues, fisheries and hydrocarbons, and environment-related industries including waste disposal, recreation, research and conservation. The rapidly developing role of information management and the role of GIS is discussed. An assessment is made of the role of organisations in international agreements, including in particular the new regional marine environment conventions forthe North East Atlantic and the Baltic, national coastal management initiatives, the NorthSea Ministerial Conferences and the European Union, with particular reference to the Common Fisheries Policy. 相似文献
13.
Daniel H. Sandweiss Kirk A. Maasch Fei Chai C. Fred T. Andrus Elizabeth J. Reitz 《Quaternary Research》2004,61(3):235-334
Understanding the influence of natural climatic variability on modern fisheries is complicated by over a century of industrial fishing. Archaeological data provide unique opportunities for assessing precolonial and preindustrial fisheries. Records show that anchoveta-vs sardine-dominated fisheries correlate with 20th-century climate change in the Pacific Basin and are linked to multidecadal climatic variability. The “anchovy regime” is characterized by cooler conditions and lower frequency El Niño/Southern Oscillation (ENSO) events, while the “sardine regime” is associated with warmer conditions and higher frequency ENSO. Fish remains excavated at Lo Demás, an Inca-period (ca. A.D. 1480–1540) fishing site at 13°25′S on the Peruvian coast, document a shift from an anchoveta-to a sardine-dominated fishery at about A.D. 1500. This shift correlates with records for increasing ENSO frequency at the same time. Middle and late Holocene sites have archaeofish assemblages that also suggest regime changes. Here we show that changes in fish regimes can result from natural variability and we support the potential role of archaeological assemblages in tracking multidecadal climate change in the Pacific Basin throughout the Holocene (0–11,500 cal yr B.P.). 相似文献
14.
In this paper, the decadal predictability and forecast skill of the Sea Surface Temperature Anomalies (SSTA) in the North Pacific and North Atlantic Ocean were investigated by conducting three sets of perfect model forecast experiments using a global coupled general circulation model. The results show that the annual mean SSTA in the North Pacific is less predictable on decadal time scale, with the forecast skill notably weaker than that of the North Atlantic. By analyzing the predictability and forecast skill of seasonal mean SSTA, it is found that the decadal predictability and forecast skill of the winter mean (JFM) SSTA in the central and western North Pacific are significantly higher than those of other seasons, and the magnitude is comparable with that of the North Atlantic. The predictability and forecast skill of the North Atlantic SSTA also show seasonal variations. Further analysis indicates that the seasonal dependence of the SSTA decadal predictability and forecast skill in the North Pacific is due to the winter-to-winter reemergence mechanism of SSTA in the North Pacific, which results from the seasonal variation of the mixed layer depth of the North Pacific Ocean. While the seasonal dependence of the North Atlantic SSTA predictability and forecast skill might be related to seasonal variations of other processes, such as the Atlantic Decadal Oscillation. The results of this paper suggest that for decadal climate prediction, if the forecast skill of the seasonal mean is taken into account, we might obtain higher than annual mean forecast skill for some seasons. 相似文献
15.
16.
James R. Coull 《GeoJournal》1996,39(2):185-194
Shetland, as an isolated group of islands on the north-west margin of Europe, has always depended in its economy on marine-based resources, and current trends suggest that this will continue for the future. Up to the oil era Shetland depended mainly on the fisheries around it, although for centuries externally-based fishermen have profited more from these fisheries than have the Shetland people. As well as the development of oil from the 1970s there has been the other major economic innovation of fish farming. The oil industry is on massive scale and has greatly changed the economy of the islands and brought notable social benefits; but the direct employment it provides is considerably exceeded by the fish-related industries, which include employment in fish processing and packing plants as well as in fish catching and fish farming. With the oil industry in Shetland now on a settled downward trajectory, the islands are inevitably now having to look more to fish-related employment for their future. In the internal structure of Shetland, fish farming has a notable effect in distributing employment throughout the islands. Activity in fishing and fish processing is more selectively located: fishing is mainly concentrated in certain islands in the archipelago, particularly Whalsay and Burra; and fish processing is mainly in central locations, especially Lerwick and Scalloway. A prominent problem for fish processors is getting reliable supplies in face of higher fish prices at markets on the Scottish mainland. The processors also now face the challenge of putting more value added on their products in an outlying location. For the future there is a major issue in getting more effective measures for conservation of fish stocks in the Shetland area; there is also the related issue of whether Shetland fishermen should get preference in the allocation of fish quotas in this area. For fish farming there is the basic issue of maintaining a pollution-free environment: this was emphasised by the oil spill from the Braer oil tanker, and there is also concern about potential polluution from the prospective development of oil fields in the more difficult deep-water environment to the west of the islands. 相似文献
17.
Salt marshes are widely believed to serve as nurseries for many fishes and crustaceans of fishery value as a result of the high production of vascular plant detritus and the protection from predation offered by shallow, spatially complex habitats. Comparisons of the yields of species which reside in salt marsh habitats during critical life history stages (such as penaeid shrimp) with the area of such habitats and their greater densities in flooded marshes and associated tidal creeks support the premise that marshes enhance the yield of such species. A range of evidence, including the amount of detrital export from marshes, the poor nutritive value of vascular plant detritus, and natural diets, casts doubt on the notion that production of fishery species is based on the direct consumption of marsh grass detritus or predominantly on food chains based on this detritus. Vascular plants and associated algae may, however, contribute to the production of prey species. The limited observations available support the hypothesis that salt marshes offer significant escape from mortality due to predation, but there have been yet few experimental tests of this hypothesis. Knowledge of relative importance of the food and refuge functions in support of living resources is of practical value in marsh and fisheries management. Better understanding of these roles is important to the effective evaluation of the effects of coastal habitat modifications on fisheries resources and design of alterations to minimize the losses of these values. 相似文献
18.
国外关键矿产战略研究进展及其启示 总被引：2，自引：0，他引：2
近年来,世界各国都将经济发展的重心向战略性新兴产业转移,为保障战略性新兴产业的发展而引发的资源安全保障问题随之而来。一些研究机构和组织纷纷开展关键矿产研究,厘定了关键矿产清单,并提出有针对性的保障措施。然而,目前国内对于关键矿产的研究才刚刚起步,对新兴产业所需矿产的研究偏少,关键矿产定量化研究的方法和指标体系总体以跟踪国外研究为主。系统地剖析了国外主要研究机构的关键矿产评价理论、模型和指标体系,总结了国外关键矿产的基本特征,并结合国内实际提出了加强部门协作、打通产业数据链、开展中国关键矿产评价理论和模型的研究、提高关键矿产供应风险治理的研究等对策建议。 相似文献
19.
Fractal Analysis of the Complexity of United States Coastlines 总被引：10，自引：0，他引：10
Coastlines have long been used as a principal example of a natural feature that exhibits fractal structure. With the advent of large digitized databases, it has become possible to examine in detail large regions of coast and to examine differences in complexity, as measured by the fractal dimension, among regions. In this study, we have determined the fractal dimension of the Atlantic and Pacific coastlines of the conterminous United States. The traditional divider method was used in obtaining the fractal dimension of each coastline arc from the NOAA Medium-Resolution Shoreline Data Set. On average, the Atlantic coast has much higher fractal dimension than the Pacific coast. The results also indicate that the complexity of the Atlantic coast increases toward low latitudes. These results have implications for the interpretation of species distributions and diversity patterns along the coast and for the understanding of the dynamics of biotic recovery from mass extinctions. 相似文献
20.
Ferromanganese crusts from the Atlantic, Indian and Pacific Oceans record the Nd and Pb isotope compositions of the water
masses from which they form as hydrogenous precipitates. The10Be/9Be-calibrated time series for crusts are compared to estimates based on Co-contents, from which the equatorial Pacific crusts
studied are inferred to have recorded ca. 60 Ma of Pacific deep water history. Time series of ɛNd show that the oceans have
maintained a strong provinciality in Nd isotopic composition, determined by terrigenous inputs, over periods of up to 60 Ma.
Superimposed on the distinct basin-specific signatures are variations in Nd and Pb isotope time series which have been particularly
marked over the last 5 Ma.
It is shown that changes in erosional inputs, particularly associated with Himalayan uplift and the northern hemisphere glaciation
have influenced Indian and Atlantic Ocean deep water isotopic compositions respectively. There is no evidence so far for an
imprint of the final closure of the Panama Isthmus on the Pb and Nd isotopic composition in either Atlantic or Pacific deep
water masses. 相似文献