Perceptions and costs of seal impacts on Atlantic salmon fisheries in the Moray Firth,Scotland: Implications for the adaptive co-management of seal-fishery conflict

The Moray Firth Seal Management Plan (MFSMP) was introduced in Scotland in 2005 as a pilot for resolving conflict between Atlantic salmon fisheries and conservation imperatives for protected harbour and grey seals. This adaptive co-management model is now being applied nationally through the Marine (Scotland) Act (2010). However, no information exists on salmon fishery stakeholders’ perceptions of seal predation impacts and related costs, which could influence the success of the MFSMP and other similar initiatives. In 2006 a questionnaire survey of the 95 salmon rod fisheries in seven major Moray Firth rivers was undertaken, and all 20 active salmon netting stations in the Firth. Forty-five fishery owners, 39 ghillies, 120 anglers and 11 netsmen (representing 17 netting stations) responded. The majority (81%) believed that seals had a significant or moderate impact on stocks and catches, 77% believed that all seals were responsible and 47% supported seal culling. Seals were sighted by 38% of rod fisheries, and 18% lost angler days from seal interference. Overall, 0.2% of total reported angler days were lost annually. The estimated direct cost of seal interference for responding rod fisheries was £14,960 annum⁻¹, and losses of catches and damage to nets was £16,500 annum⁻¹ for responding netsmen. Stakeholders’ perceptions were largely inconsistent with their low direct costs and the aims of the MFSMP. Possible reasons for this are discussed, and implications for the governance of future adaptive co-management initiatives for seal-fishery conflict.     

西藏措勤盆地油气成藏条件分析

根据野外地质调查资料,对措勤盆地的油气生成、储集、运移、圈闭等条件进行了分析;认为盆地中发育的主要烃源岩有 7套,岩石类型主要为灰岩,储集层主要为各种灰岩和砂岩;有利的生储盖组合型式主要为自生自储自盖式及互层式生储盖组合;野外调查发现的油气苗及微观包裹体的研究均证实了盆地内油气运移过程的发生;推测盆地内主要的圈闭及油气藏类型为背斜及断层遮挡油气藏,K₂-R构造层主要发育完整的背斜油气藏,J-K ₁构造层主要发育被断层复杂化的背斜油气藏;建议将主要目的层放在较新的构造层中。     

Fracture modes in the Silurian Qusaiba Shale Play,Northern Saudi Arabia and their geomechanical implications

Fracture and in-situ stress studies were conducted for unconventional prospect evaluation in the Silurian Qusaiba Shale, northern Saudi Arabia. Borehole image logs, oriented cores, seismic, and drilling observations were used in the studies. The fractures include natural fractures and induced fractures. The induced fractures were studied to assess the stress regime in terms of directions and magnitudes. The present day maximum horizontal in-situ stress trend varies from NNW-SSE to NNE-SSW, and shows a regional pattern dominated by Arabian plate tectonics. The relative magnitudes of the current day stresses are characteristic of an extensional to strike-slip regime. Natural fractures of microscopic (microfractures) to macroscopic (macrofractures) scales include extension fractures (joints/veins), and faults manifested as shear and hybrid (extensional-shear and compressional-shear) fractures. Joints clustering into zones are rare, unless when associated with fault zones. Over half of the faults (56%) show clustering into fault zones with their widths (thickness) varying by up to 5 orders of magnitude, and lengths and displacements varying by up to 4 orders of magnitudes respectively. The study identified five distinctive, regional, fracture sets: one gently dipping (bedding-parallel or at low angle to bedding) and up to four moderately to steeply dipping fracture sets: an easterly striking set is the oldest, followed by three younger major sets striking NNW-SSE, N-S, and NNE-SSW. The younger fractures are nearly parallel to the present day maximum horizontal in-situ stress. Crack-seal mechanism (natural hydrofracturing) dominates initial fracture growth, some with several phases of partial to complete mineralization or coating, dominated by calcite, quartz, and dolomite. Aqueous and hydrocarbon gaseous and fluid inclusions are common in the fractures' mineral filling. The regional nature of in-situ stresses and natural fractures means their occurrence, orientation, relative dominance, and relative age and relative apertures are easier to predict and manipulate for well planning and completion, including hydrofracturing. Forward modeling shows that natural fracture network are not critically stressed under reservoir conditions but when subjected to massive hydrofracture stimulation they and the bedding discontinuities form the seeds for the growth of a complex hydrofracture network that potentially grows out of presumed stress-barriers. Lack of stress rotation around faults in wells supports the modeling results. Microseismic monitoring gives time-lapse (incremental) microseismic events of two types; random and linear patterns parallel to maximum horizontal in-situ stress and the predominant natural fracture trend. Bulk microseismic cloud has no unique link to fault trends mapped from high resolution borehole images. This finding challenges the usability of uncalibrated microseimic monitoring of massive hydrofracturing to map faults.     

济阳坳陷阳信-花沟-平南地区CO2气藏的储层和盖层

济阳坳陷是渤海湾盆地的一个次级构造单元,其中部阳信-花沟-平南地区是主要的二氧化碳 (CO₂ )气藏产出区。该地区CO₂ 气藏的储层主要有下古生界海相碳酸盐岩、下第三系湖相碳酸盐岩和三角洲相砂岩、以及上第三系河流相砂岩。下古生界碳酸盐岩储层分布于其北部潜山带,储集空间以构造裂缝和溶蚀孔隙为主。下第三系湖相碳酸盐岩储层分布于平方王地区的沙四和沙一段。下第三系三角洲相砂岩储层主要发育于高青-平南、林樊家和阳信等地的沙河街组。上第三系河流相砂岩储层分布十分广泛,但总体来讲,其北部地层砂泥比 (5 0 %～ 70 % )较高,砂岩单层厚度 (2 0～ 40m)大,孔隙度大,渗透率高;而南部地层砂泥比小,砂岩单层厚度薄,孔隙度小,渗透率低。研究区CO₂ 气藏的盖层以泥质岩类为主,致密砾岩次之。它们均为有效盖层。沙三段、沙一段、馆陶组上部至明化镇组下部泥质岩集中段是CO₂ 气藏最重要的三大区域盖层。沙四段致密砂砾岩盖层主要分布于八里泊残丘潜山的顶部,构成潜山圈团的盖层,其渗透性很低。与烃类甲烷气藏相比,两者的储层类型基本相同,但对于盖层而言,由于CO₂气分子半径较烃类甲烷气分子半径大,因而CO₂ 气藏对盖层的要求比烃类甲烷气藏低。     

辽东湾斑海豹历史种群数量的估计

辽东湾斑海豹(Phoca largha)在本世纪里由于过度捕杀,种群数量下降比较严重。本文利用1930～1990年的捕获统计数据,对1930年以来辽东湾斑海豹的种群数量变化进行了估计。该种群在30年代初有7100头,并于1940年达到最高峰8137头,40～70年代末,由于过度捕杀,种群数量几度下降,1979年只有2269头(以上结果依据R=0.09413的种群更替率算得)。经1979～1982年徘徊以后,该种群数量迅速回升,并达到50年代末期的水平。根据0.09413,0.1163的种群更替率,对生殖力及特定年龄的死亡率进行估计。结果表明,在高比例的雌性生殖力情况下,辽东湾斑海豹幼体死亡率低于52％,成体死亡率低于16％。     

Distribution of cytochrome P4501A (CYP1A) in the tissues of Baltic ringed and grey seals

Information about the expression of CYP1A in wildlife species is essential for understanding the impact of organochlorine exposure on the health status of an exposed population. Therefore, we aimed at characterising a putative CYP1A enzyme expression in both hepatic and extrahepatic tissues of ringed and grey seals from the Baltic Sea and from less polluted waters. The cellular localisation of CYP1A was identified using a monoclonal antibody against scup P4501A1 (MAb 1-12-3). Immunohistochemical staining showed the highest level of CYP1A expression in liver hepatocytes, and the second highest level in the endothelial cells of capillaries and larger blood vessels in the liver and other organs. The most frequent and strongest staining was found in Baltic ringed seals. Although CYP1A-positive staining was observed in only a few tissues in the other seal populations, it was more intense in Baltic grey seals than in Canadian grey seals. The CYP1A enzyme activity, expressed as ethoxyresorufin O-deethylation (EROD), followed a similar tissue distribution and geographical pattern as the immunohistochemistry with clearly elevated EROD activities in most tissues of both Baltic seal populations. Immunochemical characterisation by immunoblotting confirmed the presence and elevation pattern of a putative CYP1A protein in ringed and grey seals, supporting our findings using other methods. The evenly distributed elevation of CYP1A expression among most of the tissues examined indicates that Baltic seals are exposed to CYP1A inducing agents affecting the whole body. This may result in an increased or decreased toxic potential of foreign substances, which may ultimately determine the biological effects of the contaminants.     

蒙脱石伊利石化对含油气盆地地层压力影响的定量研究

异常高压带是含油气系统研究和资源勘探领域的热点之一。本文以东营凹陷为例，定量研究了牯土矿物成岩作用对地层压力聚集的贡献。在系统分析粘土矿物组成、成岩物理化学条件的基础上，模拟计算了蒙脱石伊利石化的动力学过程，计算了脱水造成的体积变化和硅钙释放量。指出脱水作用造成的体积变化不是形成异常高压的重要因素，但硅钙的释放可能对封隔层的形成起着非常关键的作用，对地层异常压力的积聚和保持有重要贡献。