At loggerheads over international bycatch: Initial effects of a unilaterally imposed bycatch reduction policy

The Magnuson-Stevens Fishery Conservation and Management Act (MSA) is the primary law that codifies marine fisheries management in United States federal waters. The MSA was amended in 2006 with Section 610, an international provision that directs the Secretary of Commerce to unilaterally identify foreign nations engaged in the incidental capture (bycatch) of protected living marine resources (PLMRs) under specific conditions. In 2013 the United States identified Mexico for bycatch of a PLMR – the North Pacific loggerhead turtle – representing the first time a nation has been identified for bycatch under section 610. This paper evaluates the initial effects of the identification on loggerhead bycatch management efforts in Mexico and provides policy recommendations for improving the law and its implementation. In the wake of the unilateral identification, Mexico downplayed and denied the bycatch problem that their agencies had previously accepted and cancelled a bycatch research partnership between their federal fisheries science agency and U.S. researchers. Moreover, fishers invested in bycatch reduction and monitoring programs ceased to participate, jeopardizing their understanding of the problem and their co-development of bycatch solutions. However, the identification and subsequent consultation process ultimately resulted in Mexico implementing federal loggerhead bycatch regulations that are temporarily comparable with relevant U.S. measures. These regulations establish a temporary fisheries reserve (authorized for two years) that includes monitoring of bycatch, a loggerhead bycatch mortality cap, temporal and spatial restrictions on fishing gear and practices, and a closure of all finfish fisheries during the summer of 2016. As a result, turtle bycatch was likely substantially reduced in 2016, but at the cost of artisanal fishers' entire seasonal income. Policy recommendations are made, highlighting the need to: 1) better assess the socioeconomic, political, and environmental consequences associated with using the threat of trade sanctions to compel nations to reduce their bycatch; and 2) facilitate a more consistent consideration of bycatch data across nations such that the current policy does not create a disincentive for other nations to assess or report PLMR bycatch.     

海上拖航过程的风险评估方法研究

以南海某平台组块海上拖航作业为例,阐述风险评估的基本流程;针对海上拖航过程提出一套具体、实用的风险辨识、事故树建立以及建立风险控制措施的方案;同时给出一种将风险因素定性计算予以量化的方法,即风险值计算方法,并且针对海油工程确定风险值标准.     

澳大利亚冷空气活动对西北太平洋热带辐合带强度的影响

利用1959～2004年纬向风的NCEP/NCAR候平均再分析资料分析和中国科学院大气物理研究所研制的9层大气环流模式(IAP9L-AGCM)数值试验,考察了南半球越赤道气流和澳大利亚冷空气活动对西北太平洋ITCZ和台风的影响。研究发现:100°E～165°E向北越赤道气流与ITCZ的强度增强具有明显的关系;10～15 d前130°E～140°E与150°E～160°E越赤道气流的加强对145°E～170°E位置上ITCZ强度的增加具有指示意义。越赤道气流强度对同期110°E～140°E经度ITCZ位置的变化也有影响。数值试验表明:南半球澳大利亚冷空气的活动是造成越赤道气流加强的重要原因,澳大利亚地区受较强冷空气影响时易造成100°E～160°E经度带越赤道气流的加强,特别是140°E～165°E的越赤道气流有利于ITCZ强度增加,导致西北太平洋热带气旋的发生和加强。     

The wind field over wind-waves

The velocity fluctuations of wind over wind-waves in a wind tunnel are measured with a X-type hot-wire anemometer at some heights over the water surface.The observed vertical profiles of the wave-induced velocity fluctuations and the wave-induced Reynolds stress at the wave spectral peak frequency are different from those expected from the inviscid quasi-laminar model;i.e., the observed vertical profiles of the power spectral density of the wave-induced horizontal or vertical velocity fluctuations of wind have the minimum value at the height much heigher than the critical layer, and the value of the wave-induced Reynolds stress is negative at several heights over the water surface. From the comparison between the experimental results and the numerical solutions of a linear model of the turbulent shear flow over the wavy boundary, it is shown that the discrepancy described above can be attributed to the atmospheric turbulence.     

Gravity measurements over Burdwood Bank

Gravity measurements in the South Atlantic Ocean over Burdwood Bank show a large negative gravity anomaly extending along its northern edge. An interpretation of the gravity data has been made based on the seismic refraction measurements of Ludwig et al. (1968) and shows that the negative gravity anomaly can be largely attributed to a basin containing low density sediments about 8 km thick. The crustal sections constructed also indicate that the crust increases in thickness from about 20 km under Burdwood Bank to about 30 km under the Falkland Islands platform.     

Near-surface recirculation over Georges Bank

Satellite-tracked drifters with drogues centered near-surface (5 m) and below the seasonal thermocline (50 m) were launched during late winter and spring of 1988 and 1989 in the northern Great South Channel in the western Gulf of Maine to investigate the regional circulation as part of the South Channel Ocean Productivity Experiment (SCOPEX). Many of the near-surface drifters became entrained in the clockwise gyre over Georges Bank, and eight drifters made a total of 16 complete circuits around the bank during the stratified season. The average recirculation period of these eight drifters was 48 days, and the average drifter speed around the bank was 12 cm s⁻¹. There is no clear evidence from the drifter data that the strength of the clockwise gyre over the bank increased with time during the stratified season. On average, these drifters (i) followed a relatively narrow path around the bank, except over the eastern end of the bank where three preferred paths were observed, (ii) moved fastest over the northern and southern flanks of the bank, (iii) did not enter a core area of 3500 km² centered at 41°17′N, 68°00′W, approximately 30 km southwest of the topographic center of the bank, and (iv) stopped circling the bank by the end of November, due in part to strong wind events that appeared to drive drifters off the bank. Curiously, none of the near-surface drifters moved from the southern flank of Georges Bank onto the New England shelf as might be expected from continuity of flow along the outer shelf; instead, the drifters that circled the bank tended to move off the bank along its southern flank. None of the drifters with drogues centered at 50 m appeared to recirculate around Georges Bank.     

The imperishable controversy over aquaculture

Fish farming has been a recurring topic of debate, not the least in the news media. The media is an important source of information about the aquaculture industry and its products to the public. However, the media is also an important debate arena, enabling representatives of the public, stakeholders, authorities, and the industry to engage in discussions as well as to influence policy and regulations. This paper focuses on the continuous debates in news media, the topics and storylines discussed, the various actors participating, and their arguments. Through a study of the content, positions, and producers of debate contributions in nine Norwegian newspapers, this paper sheds light on the public debate on aquaculture and the present controversies. Drawing on discourse theory, it is argued that the concept of discursive conflicts offers important insights into the controversies surrounding aquaculture. Discourse coalitions unite seemingly dissimilar and independent actors, and shared story lines provide political momentum, reduce complexity and reify the debate. However, such coalitions also contribute to maintaining the debate in a deadlock.     

浙江主要气象灾害概述

气象灾害每年都有,只是轻重程度不同。就全国和全省范围来说,很少有真正风调雨顺的年份。本文根据1951～1988年38年的气象历史资料及有关政府部门的材料、简报、报道,统计出台风、洪涝、海上大风和强对流等几种主要气象灾害对浙江经济造成损失和伤亡人数。文中对主要气象灾害的特点、一般规律和灾情作了概述,并列出一些典型实例,提出了预防气象灾害的意见。     

Wave-Current Propagation over a Frictional Topography

—In this paper the parabolic approximation model based on mild-slope equation is used tostudy wave propagation over a slowly varying and frictional topography under wave-current interaction.A governing equation considering the friction effects is derived by the authors for the first time.A simpli-fied form for the rate of wave energy dissipation is presented on the basis of the wave-current action conser-vation equation and the bottom friction model given by Yoo and O＇connor(1987).Examples reveal thatthe present computational method can be used for the calculation of wave elements for actual engineeringprojects with large water areas.     

Near-neutral drag coefficients over open-ocean waves

Reanalysis of open-ocean eddy-correlation drag coefficients observed at Argus Island Tower near Bermuda indicates that near-neutral drag coefficients decrease with increasing mean horizontal wind velocity when the dominant (spectral peak) ocean wave phase velocity is much greater than the mean wind velocity. Near-neutral drag coefficients attain constant values when the dominant wave phase velocity approaches mean wind velocity, and increase again when mean wind velocity is greater than or equal to dominant wave phase velocity.     

南极洲海岛上空奇异的云彩

巴勒尼群岛沿着南极洲维多利亚地延伸达1 6 0km ,并向北延伸到新西兰海底山脉的南端。其中最南部的是斯特尔岛 (长 44km)。起码在最近半个世纪 ,岛上未见到喷发。在其他海岛中 ,记录到火山活动的有巴基岛 ( 1 83 9和1 899年 )和杨岛 ( 1 83 9年 )。2 0 0 1年 6月 1 2日 ,美国华盛顿冰况观测中心的EuDowling在研究罗斯海中的冰况时 ,根据来自卫星“NOAA 1 4、NOAA 1 5和NOAA 1 6”的资料 ,发现了面积达 2 0× 2 0 0km2 的异常云彩 ,其底部边缘悬挂在斯特尔岛上空。其顶部位于近 6 0 0 0m的高空 ,主要由冻结的水汽组成 (温度为 -5 3℃ )…     

Evolution of Interface Soliton over Topography

Several ray-type 1D and 2D KdV equations for two-layer stratified ocean with topographic effect are derived in detail in the present study.A simplified version of these equations,ray type 1D KdV equation,is used to calculate numerically the disintegration of initial interface soliton from the deep sea to the continental shelf.At the same time,a laboratory experiment is carried out in a 2D stratified flow and internal wave tank to examine the numerical results.A comparison of the numerical results with the experimental results shows that they are in good agreement.The numerical results also show that the ray-type KdV equation has high accuracy in describing the evolution of initial interface waves in shelf/slope regions.Form these results,it can be concluded that the fission process is a dominant generating mechanism of interface soliton packets on the continental shelf.     

On waves propagating over poro-elastic seabed

In this study, an analytical solution is developed for the problem of periodic waves propagating over a poro-elastic seabed of infinite depth. Water waves above the seabed are described using the linear wave theory. The poro-elastic seabed is modelled based on the Biot theory in which the inertia effect and Darcy's friction are added. Continuity of dynamic pressure and flow flux at the interfacial seabed surface are considered. Adopting an approach similar to Hsu et al. (1993), the governing equations for the pore pressure and displacements of the poro-elastic medium are derived. The present analytic solution compares favorably well with experimental results by Yamamoto et al. (1978), and analytical results by Song (1993) for the case of fine sand. Using the present theory, variations of the wavelength and fluid pressure caused by coupling of waves and the poro-elastic seabed are discussed. Results show that higher elasticity of the poro-elastic seabed induces larger interface pressure, but higher permeability causes smaller pressure on the seabed interface. The wave length is affected by the poro-elastic seabed and becomes shorter for softer seabed and shallower water depth.     

时间选择性衰落信道下的差分空时多普勒编码

对于差分编码的系统,接收端可利用差分编码自身的结构来进行解调,无需知道信道状态信息.因此基于时间选择性衰落信道的基扩展模型,提出一种新型的应用于时间选择性衰落信道下多输入多输出系统的差分空时多普勒(DSTD)编码方案,由该方案组成的系统可以配备任意数目的发送和接收天线.该DSTD系统发送端由频谱编码器、差分编码器和OFDM调制器串联组成,能提供最大空间-多普勒分集增益和显著的编码增益.差分编码器中酉结构的引入可以实现线性空时分离的最大似然检测,降低了译码的复杂度.仿真分析表明与已有差分系统相比,文中所提出的差分编码方案可以获得更高的分集增益.     

Hydraulic roughness over simple subaqueous dunes

Detailed studies of flow over subaqueous dunes in laboratory flumes were used to suggest a virtual near-bed layer of twice the dune height in which the mean velocity is accelerated towards the crest by contraction. The mean flow velocity in this layer above the crest, transformed into friction velocity by means of the surface skin roughness, is shown to give values consistent with measured values. The resulting dimensionless shear stress due to skin friction is depth-independent, in contrast to that derived by means of often cited traditional methods. As a result of the relationship between dune height and the thickness of the near-bed layer, an expression for the expansion loss behind dunes was formulated and used to relate form resistance directly to dune height.     

北美洲冬季冷空气对南美洲夏季降水异常影响的研究

利用1981—2017年NCEP/NCAR再分析资料和ECMWF再分析资料,研究了北美洲冬季高纬度冷空气对南美洲夏季降水异常的影响。结果表明,北美洲冬季高纬度冷空气通过影响向南越赤道气流的强弱,影响南美洲热带辐合带(intertropical convergence zone,ITCZ)位置和强度的变化,进一步引起南美洲天气的变化。北美洲冬季冷空气的南下过程能够引起80°～70°W的向南越赤道气流明显加强,导致2011年南美洲热带辐合带的位置异常偏南,强度异常偏强,是造成降水异常偏多的重要成因。通过相关分析发现北美洲冬季冷空气对南美洲ITCZ位置的影响更明显。     

Seafarers' access to jurisdictions over labour matters

The Maritime Labour Convention, 2006 outlines a framework for states to enforce jurisdiction over maritime labour matters, including the Flag State, Port State and Labour Supplying State. However, the Convention does not provide explicit guidance on jurisdiction determination. This article argues that seafarers should have the right to access the jurisdictions of member states, and that future amendment to the Convention should confirm this right. This paper first analyses current theories of maritime labour jurisdiction. Secondly, it conducts a comparative doctrinal analysis regarding adjudicative jurisdiction principles in common law and civil law systems. Thirdly, in three case studies involving concurrence jurisdictions of member states, this article finds that the authority of any single member state is not reliably accessible to seafarers, in particular when the state has no strong link with the seafarers. This article recommends that seafarers’ rights in the Convention to choose one jurisdiction from relevant member states should be confirmed in a future amendment.