Legal aspects of conserving native oysters in Scotland

Native oysters (Ostrea edulis) historically supported valuable fisheries in Scotland, but are now absent from areas of former abundance on the east coast and occur mainly in isolated populations in west coast sea lochs. The main contemporary threat is from unauthorized gathering. In most places, the exclusive right to gather is retained by the Crown, as a remnant of the feudal system, but in some areas the right has been acquired by individuals or institutions. A temporary right to gather oysters may be obtained by permit from the proprietor, or through a Several or Regulating Order made under shellfish fisheries legislation. The right to gather oysters is separate from ownership of the foreshore or sea bed on which they are located. To receive the maximum legal protection, oyster beds must be marked out, or the rights to them otherwise adequately made known. Wild or formerly-cultivated oyster beds may not meet this criterion and, in any case, enforcement is difficult in remote locations. It has been proposed that there should be a statutory public right to gather oysters. Were this to be created, then strong conservation measures would need to be implemented to protect native oysters from eradication by uncontrolled gathering.     

Water pollution and habitat degradation in the Gulf of Thailand

The Gulf of Thailand has been a major marine resource for Thai people for a long time. However, recent industrialization and community development have exerted considerable stress on the marine environments and provoked habitat degradation. The following pollution problems in the Gulf have been prioritized and are discussed in details: (1) Untreated municipal and industrial waste water are considered to be the most serious problems of the country due to limited waste water treatment facilities in the area. (2) Eutrophication is an emerging problem in the gulf of Thailand. Fortunately, the major species of phytoplankton that have been reported as the cause of red tide phenomena were non-toxic species such as Noctiluca sp. and Trichodesmium sp. (3) Few problems have been documented from trace metals contamination in the Gulf of Thailand and public health threat from seafood contamination does not appear to be significant yet. (4) Petroleum hydrocarbon residue contamination is not a problem, although a few spills from small oil tankers have been recorded. A rapid decrease in mangrove forest, coral reefs, and fisheries resources due to mismanagement is also discussed.     

Jointly thinking the post-dam future: exchange of local and scientific knowledge on the lakes of the Lower Rufiji,Tanzania

Abstract

A large dam is planned at Stiegler’s Gorge in Tanzania. The change in the Rufiji River flood pattern will affect downstream ecosystems. This paper concentrates on the highly productive floodplain lakes that play a vital role in local livelihoods. A participatory monitoring system with village-based observers collected water level, rainfall, fisheries and food data from 2001 to 2011. Water balances of the lakes show dependence on the Rufiji River flood, with varying vulnerability. With the dam design flood of 2500 m³ s^-1, lakes with a high threshold and small catchment will dry out quickly. Lakes with a lower threshold and substantial catchment are more robust but may still dry out during prolonged local drought. Analysis of rainfall (1923–2012) indicates a recent decrease. The data were analysed through feedback workshops with local observers, government technical staff and researchers. Through this collaborative approach, local capacity in preparing for the post-dam future was enhanced.

Editor D. Koutsoyiannis; Guest editor M. Acreman

Citation Duvail, S., Mwakalinga, A.B., Eijkelenburg, A., Hamerlynck, O., Kindinda, K., and Majule, A., 2014. Jointly thinking the post-dam future: exchange of local and scientific knowledge on the lakes of the Lower Rufiji, Tanzania. Hydrological Sciences Journal, 59 (3–4), 713–730.     

关于井炮激发参数优化设计的思考

利用正演模拟的手段进行分析,对影响井炮激发的不同影响因素展开分析,结合对炸药特征阻抗与围岩的阻抗匹配系数、炸药几何耦合系数、激发药量、井深等方面进行分析,对井炮激发参数进行优化设计.通过优化设计,寻求有效提高地震子波品质的方法.结合实际的地震地质条件和地震勘探目标,设计最佳的井炮激发参数,提高地震勘探的效益.     

Acoustic characteristics of fish bombing: potential to develop an automated blast detector

The use of explosives to catch fish has caused extensive damage to coral reefs throughout Southeast Asia, but the frequency with which they are used is largely unknown. The aim of this work is to develop a detection system capable of distinguishing underwater explosions from background noise, and locating their origin by triangulation. Blast signals have been recorded over a range of distances and the key features that differentiate them from background noise have been determined. For small charges the effective range of such a detector is more than 12 km and may extend up to 50 km depending on the mass of the charges being used. Such a system would help to determine the scale of the problem, identify areas at greatest risk and quantify the effectiveness of management intervention designed to control destructive fishing practices. It may assist with fisheries enforcement in some areas.     

地震勘探中的炸药震源药量理论与实验分析

炸药由于具有良好的脉冲特性及高能量的特点而作为地震勘探中的主要震源，就炸药本身来说，在地震勘探中药量、井深等参数的选取对激发能量和激发频率有很大的影响。为此，本文运用炸药爆炸理论，从炸药作功角度来加以论述，并通过理论和实验分析得出选取一个最佳的药量和井深激发，既能提高炸药作功能力，又能增强激发能量，从而激发强能量的高频震源子波，达到指导野外地震采集和节约经济成本的目的。     

Pollution studies in the Clyde Sea area

The Firth of Clyde on the west coast of Scotland is a major seaway and vacation area, it supports important commercial fisheries and receives domestic, industrial and agricultural wastes from a catchment area with a population of well over 2 million. The Department of Agriculture and Fisheries for Scotland has a continuing investigation of the area to keep track of the increasing threat of pollution, particularly to the fishing industry.     

论中国半精养水库渔业及其饲料问题

中国水库放养鱼的种类、食性以及可利用的天然饵料生物决定了半精养渔业是水库渔业的主要模式。水库半精养有中、小型水库、水库库汊、网拦、网围、网箱养鱼等多种形式。其产量与肥料、饲料的投入有直接关系。最大限度地利用天然饵料,并辅以补充性人工饲料,可实现高产高效。本文以水库鱼类的营养和饲料利用为基础,论述半精养水库渔业的理论和实用技术,并提出尚须研究的问题,以推进半精养水库渔业的发展。     

Establishing a spatial map of health risk assessment for recreational fishing in a highly urbanized watershed

Recreational fishing is a popular activity in many urbanized watersheds. When river water is incidentally ingested during fishing sessions, substantial waterborne fecal contamination can cause adverse health effects. This study aims to spatially map health risks for recreational fishers caused by waterborne Escherichia coli (E. coli) in the highly urbanized Tamsui River watershed. First, indicator kriging was used to probabilistically estimate the distributions of waterborne E. coli and determine the conditional cumulative distribution function (CCDF). Subsequently, to propagate the parameter variability, Monte Carlo simulation was adopted to characterize the ingestion rate and exposure duration for recreational fishers and E. coli realizations were generated using random fields on the basis of the estimated CCDF. Finally, after the three parameters were combined, the approximate beta-Poisson dose–response function was employed to quantitatively determine potential risks to recreational fishers in the Tamsui River and its tributaries. The analysis results revealed that the risks of recreational fishing exceed an acceptable level of 8 infections per 1000 fishers per day at several urban river courses. Therefore, recreational fishing activities in urban riverbanks pose a substantial health threat. Recreational fishing in urban riverbanks should be limited before the construction of complete sanitary sewer systems. The river mouth and certain upstream river sections are suitable for the development of recreational fishing.     

Ocean in peril: Reforming the management of global ocean living resources in areas beyond national jurisdiction

This article presents the outcome of research aimed at assisting governments in meeting their commitments and legal obligations for sustainable fisheries, based on increasing evidence that global fisheries are in crisis. The article assesses the effectiveness of the existing legal and institutional framework for high seas living resources. It focuses on: (1) the role of regional fisheries management organizations (RFMOs); (2) tools for compliance and enforcement to stem illegal fishing; and (3) mechanisms for habitat protection. The article further highlights a variety of options for addressing key weaknesses and gaps in current ocean governance, including United Nations General Assembly (UNGA) resolutions, reforms at the regional level, as well as a possible new legal instrument, with a view to informing international discussions on ways to ensure the sustainable use of high seas resources without compromising the health of the marine environment.     

Estimating tsunami inundation from hurricane storm surge predictions along the U.S. gulf coast

Gulf of Mexico (GOM) coasts have been included in the U.S. Tsunami Warning System since 2005. While the tsunami risk for the GOM is low, tsunamis generated by local submarine landslides pose the greatest potential threat, as evidenced by several large ancient submarine mass failures identified in the northern GOM basin. Given the lack of significant historical tsunami evidence in the GOM, the potential threat of landslide tsunamis in this region is assessed from a worst-case scenario perspective based on a set of events including the large ancient failures and most likely extreme events determined by a probabilistic approach. Since tsunamis are not well-understood along the Gulf Coast, we investigate tsunami inundation referenced to category-specific hurricane storm surge levels, which are relatively well established along the Gulf Coast, in order to provide information for assessing the potential threat of tsunamis which is more understandable and accessible to emergency managers. Based on tsunami inundation studies prepared for the communities of South Padre Island, TX, Galveston, TX, Mobile, AL, Panama City, FL, and Tampa, FL, we identify regional trends of tsunami inundation in terms of modeled storm surge inundation. The general trends indicate that tsunami inundation can well exceed the level of storm surge from major hurricanes in open beachfront and barrier island regions, while more interior areas are less threatened. Such information can be used to better prepare for tsunami events as well as provide a preliminary estimate of tsunami hazard in locations where detailed tsunami inundation studies have not been completed.     

Klauder wavelet removal before vibroseis deconvolution

The spiking deconvolution of a field seismic trace requires that the seismic wavelet on the trace be minimum phase. On a dynamite trace, the component wavelets due to the effects of recording instruments, coupling, attenuation, ghosts, reverberations and other types of multiple reflection are minimum phase. The seismic wavelet is the convolution of the component wavelets. As a result, the seismic wavelet on a dynamite trace is minimum phase and thus can be removed by spiking deconvolution. However, on a correlated vibroseis trace, the seismic wavelet is the convolution of the zero-phase Klauder wavelet with the component minimum-phase wavelets. Thus the seismic wavelet occurring on a correlated vibroseis trace does not meet the minimum-phase requirement necessary for spiking deconvolution, and the final result of deconvolution is less than optimal. Over the years, this problem has been investigated and various methods of correction have been introduced. In essence, the existing methods of vibroseis deconvolution make use of a correction that converts (on the correlated trace) the Klauder wavelet into its minimum-phase counterpart. The seismic wavelet, which is the convolution of the minimum-phase counterpart with the component minimum-phase wavelets, is then removed by spiking deconvolution. This means that spiking deconvolution removes both the constructed minimum-phase Klauder counterpart and the component minimum-phase wavelets. Here, a new method is proposed: instead of being converted to minimum phase, the Klauder wavelet is removed directly. The spiking deconvolution can then proceed unimpeded as in the case of a dynamite record. These results also hold for gap predictive deconvolution because gap deconvolution is a special case of spiking deconvolution in which the deconvolved trace is smoothed by the front part of the minimum-phase wavelet that was removed.     

Fisheries: Hope or despair?

Recent work suggesting that fisheries depletions have turned the corner is misplaced because analysis was based largely on fisheries from better-managed developed-world fisheries. Some indicators of status show improvements in the minority of fisheries subjected to formal assessment. Other indicators, such as trophic level and catch time series, have been controversial. Nevertheless, several deeper analyses of the status of the majority of world fisheries confirm the previous dismal picture: serious depletions are the norm world-wide, management quality is poor, catch per effort is still declining. The performance of stock assessment itself may stand challenged by random environmental shifts and by the need to accommodate ecosystem-level effects. The global picture for further fisheries species extinctions, the degradation of ecosystem food webs and seafood security is indeed alarming. Moreover, marine ecosystems and their embedded fisheries are challenged in parallel by climate change, acidification, metabolic disruptors and other pollutants. Attempts to remedy the situation need to be urgent, focused, innovative and global.     

中国水库渔业的现状与趋势

本文对我国水库渔业的经济特色、发展简史、生产类型、生态模式、渔业规划与渔业经济、主要增养殖技术进行了比较系统地总结,对水库渔业的潜力和存在的问题作了初步分析,并扼要预测了我国水库渔业将来的可能趋势。     

Anthropogenic effects on the smalltooth sawfish (Pristis pectinata) in the United States

Bycatch mortality in net fisheries was the major reason for the decline of the endangered smalltooth sawfish, Pristis pectinata, in the United States. These fisheries have been reduced or eliminated in some states including Florida--where most smalltooth sawfish are currently found in the United States. To determine whether other factors are still affecting this species, we obtained non-net fishery entanglement, injury, and mortality data by soliciting information from anyone who may have encountered this species. Smalltooth sawfish were damaged by marine pollution (e.g., polyvinyl chloride pipe, monofilament line, non-monofilament line) and injured by humans. Examples of injuries caused directly by humans include removal of rostra, shooting an individual with a powerhead, and shooting another with arrows. Many people are aware that the smalltooth sawfish is protected by state and federal laws, but some are still not aware of (or willing to accept) this status. The impacts of marine pollution and injuries directly caused by humans on this endangered species can be ameliorated by incorporating fisher education into the conservation and management processes.     

Effects of the Jessica oil spill on artisanal fisheries in the Galápagos

In contrast to local perceptions, the impact on the local Galápagos artisanal fishery of the 16 January 2001 grounding of the Jessica and subsequent oil spill was relatively minor. No significant changes in fishing effort, total fishing catches or catch-per-unit effort were detected after the spill based on analyses of fisheries monitoring data. Nevertheless, large boats tended to move away from sites near the path of the spill following the grounding in 2001, with no fishing recorded from the oil-affected regions of Floreana and southern Isabela in February 2001. The total fishing effort of small boats operating from the Jessica-grounding island of San Cristóbal also declined immediately after the spill, probably in part because such boats were used in clean up operations. During 2001, prices paid to fishers remained stable at levels higher than in 2000, with the notable anomaly that prices fell precipitously to 30% of previous levels during a 1-2 week period in early February 2001. Fish exports remained at similar levels for the years 2000 and 2001; however, as in the previous year, little fish product was exported from Galápagos in the month following the spill, with most fish product dried and stored for up to two months prior to transport to the continent.     

Coastal resource degradation in the tropics: does the tragedy of the commons apply for coral reefs, mangrove forests and seagrass beds

The keynote paper by Garrett Hardin 44 years ago introduced the term 'tragedy of the commons' into our language (Hardin, 1968); this term is now used widely, but it is neither universally accepted nor fully understood. Irrespective, the 'tragedy of the commons' is an increasing reality for more than 500 million people that rely on the biodiversity resources and services of tropical coral reefs, mangrove forests, seagrass beds and associated fisheries. These natural resources continue to decline despite major advances in our scientific understanding of how ecosystems and human populations interact, and the application of considerable conservation and management efforts at scales from local user communities to oceans. Greater effort will be required to avert increasing damage from over-exploitation, pollution and global climate change; all deriving from increasing exploitation driven by poverty and progress i.e. continuing to expand development indefinitely and extraction of resources at industrial scales. However, the 'tragedy' concept has been widely criticized as a simple metaphor for a much larger set of problems and solutions. We argue that the 'tragedy' is essentially real and will continue to threaten the lives of millions of people unless there are some major moral and policy shifts to reverse increasing damage to coastal habitats and resources. We agree with the conclusion by Hardin that the solution to the tragedy will not be through the application of natural sciences, but via implementing exceedingly difficult and controversial moral decisions. An extreme example of a moral and controversial direction suggested by Hardin was in re-examining the 'freedom to breed' as an inherent human value. The need for 'moral decisions' is even greater in 2012.     

The Rehabilitation of the Tampa Bay Estuary, Florida, USA, as an Example of Successful Integrated Coastal Management

The Tampa Bay Ecosystem is located in the state of Florida, USA. The 6739 km² ecosystem has undergone major changes due to coastal development, including dredging for maintenance and expansion of the 10th largest port in the USA. Approximately 44% of the historic emergent coastal wetlands and 81% of the historic submergent seagrass meadows had been lost through 1981. Declines in commercial and recreational fisheries harvests and coastal wildlife populations followed similar trends in declines. Beginning three decades ago, an informal Integrated Coastal Management (ICM) program initiated by citizen groups has progressed to a formal ICM program that has initiated restoration of the ecosystem and management through a unique multi-county umbrella organization, the Tampa Bay Estuary Program.     

虚反射界面对地震激发效果的影响及其应用

在地震资料采集过程中,表层虚反射界面对地震波的激发效果影响较大,但也是确定炸药震源激发深度的重要因素之一.本文讨论了确定炸药震源距虚反射界面距离的有效方法,分析了复杂地表条件下虚反射界面对地震激发的影响,阐述了如何用之选择最佳激发井深,尽可能地减小由震源产生的各类次生干扰,获得频率响应较好的地震激发子波,以便采集到理想的地震资料.     

A model of fish preference and mortality under hypoxic water in the coastal environment

Eutrophication and associated occurrence of hypoxic condition could cause significant damage to marine ecosystems, resulting in considerable economic losses to fisheries and aquaculture and is a major source of stress that fish often have to contend with in order to survive. This problem is likely to be exacerbated in the coming years, since the wastewater treatment facilities is unlikely to catch up with increasing human activities. Moreover, large-scale reclamation projects in coastal areas have recently been increased, and these activities certainly have adverse impacts on water quality and fisheries resources. Coastal construction has a significant role in the development of hypoxic water by changing the current and mixing pattern of water. Changes in species composition and decreases in species richness and diversity have been well documented in hypoxic systems. Hypoxia could cause endocrine disruption in fish and eliminate populations of sensitive species. Shallow coastal areas are of great importance for the special nursery of fish and shellfish and land reclamation in these areas cause strong damage to fisheries. Although the tolerance of aquatic life to hypoxia is known, there is no information about the mortality of fish caused by hypoxia because fish can swim around it and no modeling study has yet been carried out. Criteria that influence the movement of fish are: amounts of food, water temperature and depth, dissolved oxygen concentration and nature of seabed. However, among these, water temperature and dissolved oxygen are the most crucial parameters that affect survival, movement and growth of fish. In this paper, a model of fish preference and mortality for environmental conditions was developed and applied to the Hakata Bay where hypoxic water occurs every summer. For the purpose of this study, a field survey of fish behavior under hypoxic water was conducted by releasing marbled sale (Pleuronectes yokohamae) in the inner bay. Moreover, a series of preference tests for DO, salinity and temperature in the laboratory were conducted in order to decide preference parameters of fish. Using the results of both field and laboratory studies, a sub-module of fish preference and mortality was coded within an integrated hydrothermal and eutrophication model (CHEM) to predict the behavior and mortality of marbled sale when hypoxia would occur in the bay. The model could reasonably simulate the behavior of the fish under hypoxia. An assessment of the impact of the ongoing land reclamation project of about 401 ha in the Wajiro tidal flat zones at the head of the bay on the fisheries resources was also conducted using the model. The results showed that the artificial land lowered the mortality rate of fish under hypoxic condition in the bay during the summer period.