TAC management in North Sea flatfish fisheries

The Common Fisheries Policy of the European Union adopted in 1983 is primarily focused on a science-based TAC management system with fixed national quota shares. The quality of the assessments of plaice and sole, the consistency of the scientific advice, the congruency of the management decisions, and the enforcement of the regulations are reviewed over a 15-year period. The conclusion is that there have been problems at each level, with the ultimate effect that the policy has not been able to restrict fishing mortality and that the level of overexploitation has only increased. It is argued that the present TAC system has created more problems than it has resolved. Attention is drawn to the autonomic economic developments within the fishery and to the potential for managing the fishery more effectively from the cost side rather than the profit side.     

半滑舌鳎仔稚鱼消化酶活性的变化

对半滑舌鳎不同发育阶段主要消化酶（酸性蛋白酶、碱性蛋白酶、淀粉酶、脂肪酶）以及与消化吸收相关的碱性磷酸酶的活性变化进行了测定。结果表明，半滑舌鳎在仔鱼发育早期即可检出酸性蛋白酶和碱性蛋白酶的活力，碱性蛋白酶的2个极低值分别出现在仔鱼开口期和仔稚鱼的转交期，从孵化后23d左右胃腺出现时，酸性蛋白酶的活性开始明显升高。早期仔鱼体内表现出较强的淀粉酶活性，孵化后12d其活性急剧下降，并一直保持较低的比活力状态。脂肪酶的活性在半滑舌鳎早期仔鱼体内一直较低，进入稚鱼期后开始缓慢上升。碱性磷酸酶活性在变态结束后出现大幅度的升高，这标志着肠组织结构和肠道消化功能的完善。     

Geochemistry and tectonic significance of metamorphic sole rocks beneath the Beyşehir–Hoyran ophiolite (SW-Turkey)

The Beyşehir–Hoyran ophiolite is situated in the western part of the Tauride belt (SW Turkey) and crops out at two localities north of the lake Beyşehir. It mainly comprises harzburgitic peridotites that were tectonically emplaced to their present position during the Late Eocene. The ophiolites themselves are tectonically overlain by either slope basin deposits with lava blocks (Eğirler formation) or massive Triassic limestone blocks (Deliktaş formation). High-grade sub-ophiolitic metamorphic rocks, i.e. epidote amphibolite, amphibolite, and pyroxene amphibolite, together with minor quartzite and calcschist, are observed at the base of the ophiolite sequence, where they occur as thin tectonic slices with an inverted metamorphic gradient. Average P–T conditions of 630–770 °C and c. 6 ± 1.5 kbar are calculated for the metamorphism of the amphibolites by conventional geothermobarometry, corresponding to a burial depth of 18–20 km. Both the sub-ophiolitic metamorphic rocks and the overlying mantle tectonites were intruded by isolated tholeiitic (Nb/Y = 0.041–0.108) diabase dikes, which do not transect the tectonic contact between the two units. Geochemical investigations of the amphibolites of the sub-ophiolitic rock suite show two different geochemical affinities, with the first group being alkaline in character (Nb/Y = 1–3.86) and the second one being tholeiitic (Nb/Y = 0.064–0.13). REE patterns, trace element plots and tectonomagmatic discrimination diagrams indicate that the most probable protoliths for alkaline amphibolites are within-plate type alkali basalts, whereas those of the tholeiitic group resemble tholeiitic island arc basalts. Similarities between the geochemical characteristics of the amphibolites and those of the volcanic rocks of the Eğirler formation strongly suggest that the latter are the protoliths of the amphibolites.     

Half Smooth Tongue Sole(Cynoglossus semilaevis) Under Low Salinity Stress Can Change Hepatic igf2 Expression Through DNA Methylation

Salinity is a crucial environmental stress that severely affects fish growth and survival.Under environmental stress,DNA methylation plays an important role in gene expression and genome function.To better understand the epigenetic regulation mechanism of igf2 under low salinity stress,we analyzed the DNA methylation at 5’UTR,exon1,intron1,and exon2,and analyzed the relationship of DNA methylation with mRNA abundance as well as the special single CpG sites methylation patterns of igf2 in the liver of half smooth tongue sole under low salinity(15)for 0,7,and 60 d.When exposed to low salinity,DNA methylation at 5’UTR and exon2 remained stable,while it was up-regulated firstly and then down-regulated at exon1 and intron1.Some single CpG sites of igf2 associated with low salinity,and most of these sites with significantly changed methylation levels(P<0.05)are located in intron1 area.The discrepant variation of single CpG sites methylation levels and igf2 expression further revealed that females and males showed different response to low salinity.Remarkably,the 38-CpG site of intron1 servers as a sexual marker.Additionally,our integrative analysis demonstrated that regional DNA of igf2 methylation had highly complex interplay on gene expression.The single CpG sites in intron1 were indispensable epigenetic markers under external environmental stress.Above all,to resist the low salinity stress,half smooth tongue sole liver can regulate the expression of igf2 through methylation of CpG sites in intron1.     

线纹舌鳎(Cynoglossus lineolatus)18S rRNA基因长片段复制:不等交换模型(unequal crossing over model)罕见的分子证据

尽管18S rRNA基因序列极其保守,但是在一些种类中仍然发现其存在序列多态性。本研究在线纹舌鳎18S rRNA基因中发现了3种差异显著的序列类型（Type A,B和C）,说明其为非协同进化,而不是严格遵循协同进化方式。基于以上三种类型序列GC含量、二级结构、最小自由能等差异,我们推测Type A和B可能是假基因类型。此外,在Type A类型中还发现了一段长达189 bp的重复序列。据我们所知,如此长的重复序列,这在硬骨鱼类核糖体基因中还是首次报道。通过比较分析产生重复序列常见的模型,我们认为不等交换模型最有可能解释该重复序列的形成。本研究结果不仅为不等交换模型提供了罕见的分子证据,而且为鱼类18S rRNA基因研究奠定了很好的基础。     

Kinematics and U-Pb zircon ages of the sole metamorphics of the Marmaris Ophiolite,Lycian Nappes,Southwest Turkey

ABSTRACT

In the eastern Mediterranean, the Lycian Nappes are found in the structurally uppermost position in the Anatolide-Tauride belt related to the closure of the Neotethys. In Western Turkey, the Marmaris Ophiolite with the metamorphic sole occupies the uppermost tectonic position in the Lycian belt. The metamorphic sole is represented by discontinuous tectonic slices composed of amphibolites, phyllites, micashists and quartzo-feldspathic micaschists. Zircons from the micashists and quartzo-feldspathic micaschists display dark cores and rims. The cores yield ages between 229 and 175 Ma, inner rims yield ages between 153 and 143 Ma and the outer rims show a concordia age of 96.7 ± 0.79 Ma. In terms of their Th/U ratios, the cores and inner rims indicate igneous origin, whereas the outer rims indicate accretion during metamorphism. By dating of these zircons, the deposition time for the protolith of micaschists and quartzo-feldspathic micaschists could be constrained as the Early Cretaceous. Present-day orientation of the kinematic data from the sole metamorphics and the uppermost part of the Karabörtlen formation clearly suggest a top-to-the NE sense of shear. By taking into account the 25^º–30^º anticlockwise post-emplacement rotation of Southwest Turkey, it follows that the Lycian Nappes were emplaced eastward onto the Menderes Nappes. This tectonic model disagrees with the previous tectonic models suggesting northward or southward movement of the Lycian Nappes onto Menderes Nappes.     

Characterization of cholinesterases in marbled sole, Limanda yokohamae, and their inhibition in vitro by the fungicide iprobenfos

Cholinesterases (ChEs) have been characterized in marbled sole (Limanda yokohamae) for use as a possible biomarker of pollution exposure. In brain, ChEs existed almost exclusively (>95%) as acetylcholinesterase (AChE) whereas in muscle, about 20-30% of ChE activity was in the form of butyrylcholinesterase (BChE; pseudocholinesterase). Acetylthiocholine and butyrylthiocholine (identified in mammalian studies as diagnostic substrates for AChE and BChE respectively) were hydrolyzed mainly, but not exclusively, by these enzymes. The inhibitors BW284C51 and iso-OMPA (identified in mammalian studies as diagnostic inhibitors of AChE and BChE respectively) were not specific for these enzymes in marbled sole. Brain AChE and muscle AChE and BChE were characterized in terms of their kinetic properties (KM etc.) and optimal conditions (substrate concentration, protein concentration, pH etc.) were established to allow routine assays of ChE activity to proceed under pseudo-first order conditions. The sensitivity of ChEs to a locally significant pesticide, iprobenfos (IBP; kitazin) was established in terms of IC50 concentrations. Brain AChE was relatively insensitive to IBP, but muscle AChE and BChE were sensitive to IBP concentrations in the high nM range. However, ambient IBP concentrations in Korean coastal waters are usually not high enough to cause detectable ChE inhibition in this species.     

半滑舌鳎雌性特异fosmid克隆的筛选及FISH定位

通过对半滑舌鳎雌鱼fosmid文库进行有序混合,成功构建了两步-三维PCR筛选体系,为后续的基因筛选奠定了基础。通过对半滑舌鳎W染色体文库序列进行引物设计,并分别在雌、雄鱼基因组DNA中筛选,获得1对雌鱼特异性引物。使用该引物对fosmid文库进行筛选,得到1个雌鱼特异性克隆,并通过荧光原位杂交技术将克隆定位到了W性染色体上,证实了使用该体系进行文库筛选的有效性以及雌鱼引物的特异性,建立了半滑舌鳎遗传性别的分子及细胞遗传学鉴定方法,为后续半滑舌鳎基因组及性染色体的研究奠定了基础。