From Vagrant to Resident: occurrence,residency and births of leopard seals (Hydrurga leptonyx) in New Zealand waters     

《新西兰海洋与淡水研究杂志》2012,46(1):1-23

ABSTRACT

In contrast to previous reports that leopard seals (Hydrurga leptonyx) are rare vagrants to New Zealand, we show that this species is a regular member of the marine fauna of this region. We present a first analysis from the New Zealand Leopard Seal Database – an extensive collation of 2,711 records of leopard seals within New Zealand between 1200 and 2018. Of these records, 51.2% (n?=?1,408) were photographic. Leopard seal sightings have increased over time and been reported in all seasons and regions of New Zealand. Sightings are predominantly of adult individuals of good or excellent body condition, which differs to previous hypotheses suggesting that leopard seals visiting New Zealand shores are primarily juvenile animals in poor health condition. A total of 176 unique individuals have been identified in the New Zealand Leopard Seal Catalogue between 2014 and 2018 and preliminary results indicate that numbers per annum have continued to increase over time. Three leopard seal births and a number of juvenile animals (34% of the NZ records) have been documented. Considering the information presented here and the current definitions in the New Zealand Threat Classification System, the threat status of leopard seals within New Zealand waters should be reclassified from Vagrant to Resident.  相似文献   

人工鱼礁对山东莱州朱旺港海区游泳动物的群落结构及季节变化的影响   总被引：1，自引：0，他引：1  

徐浩  曾晓起  顾炎斌  关丽莎 《中国海洋大学学报(自然科学版)》2012,42(5):47-54

为查明朱旺港人工礁区游泳动物的群落结构特征及其季节变化,于2010年5～11月和2011年3月对该海域人工礁区和自然对照区进行逐月调查.结果表明,人工礁区游泳动物种类比对照区丰富(1.42倍);并且人工礁区的Margalef种类丰富度指数、Shannon-Wiener多样性指数、Pielou均匀度指数均高于对照区.人工礁区的CPUE也明显高于对照区,人工礁区的Al区(建于2008年)和A2区(建于2009年)分别是自然对照区CA区的1.43和1.55倍,其中经济种类日本蟳的CPUE分别达到2.69和2.97倍.初步体现人工鱼礁投放后的集鱼效果,且礁区游泳动物的群落结构有明显改善.  相似文献   

人工航道疏浚对近岸沉积的影响——以葫芦岛港为例     

王亮  范德江  张喜林  刘明  邵和宾  张现荣 《中国海洋大学学报(自然科学版)》2012,(10):88-96

航道疏浚是海岸带人类活动的重要形式之一,对近岸海洋环境有着重要的影响。本研究以葫芦岛航道疏浚为例,通过X射线衍射物相分析、放射性同位素分析和激光粒度分析等方法,对航道疏浚区及邻近海域沉积物进行了系统的研究,结果表明:(1)航道疏浚产生的沉积物与现在海底沉积物在粒度组成、黏土矿物组合和210 Pb、137 Cs放射性强度等方面具有显著的差异,可以作为示踪航道疏浚物质扩散和影响范围的指标;(2)葫芦岛海域的航道疏浚物在潮流的作用下沿西北和西南2个方向扩散,不同程度地加入到表层沉积物中,个别地方疏浚沉积物直接覆盖到原沉积物之上,导致海底原地沉积物属性的改变。  相似文献   

澳大利亚西北陆架深水盆地油气分布规律     

冯杨伟  屈红军  张功成  郑艳荣 《地质科技情报》2011,30(6):99-104

澳大利亚西北陆架边缘海型被动大陆边缘是目前全球深水区油气勘探的热点地区之一,近年来的一系列深水(＞500m)油气重大发现使其备受关注.澳大利亚西北陆架油气分布总体上具有显著的不均一性.平面上呈“内油外气”的分布特征,油气主要分布于富烃凹陷的凹边隆和凹中隆.远岸带深水区发育大型、超大型气田且成群成带分布,近岸带浅水区以发育中、小型油田为主,亦成群成带分布.纵向上呈“上油下气”的分布特征,天然气和凝析油主要富集于上三叠统和中-下侏罗统,石油主要富集于上侏罗统和下白垩统.  相似文献   

Paleoclimatic inference of the mid-Holocene record of monk seal (Monachus monachus) in the Cantabrian Coast     

A.B. Marín  M.R. González-Morales 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(1):113-124

The mid-Holocene has been widely used to test the performance of the numerical models that are commonly employed to estimate the future evolution of world climate. This period, as the pollen record shows, was characterized by higher temperatures than present in northern and Central Europe, while cooler conditions occurred in the south of the continent. This pattern is challenging numeric algorithms that widely fail to replicate the paleoclimate data of southern Europe. Here we report the discovery of a fragmented bone of a temperate water phocid (Monachus monachus) dated to 5540 ± 40 BP that was hunted and consumed on the Cantabrian Coast during that period. This find implies a hitherto unnoted phase of warm conditions associated with strengthened advention of subtropical waters to the region. As a consequence, the possibility that the oceanographic regime from that time in the Bay of Biscay was similar to the current one is reinforced, a fact that could modify our view of mid-Holocene climate in the Iberian Peninsula and have important implications in climate change studies.  相似文献   

Ecological periodic tables for benthic macrofaunal usage of estuarine habitats in the US Pacific Northwest     

Steven P. Ferraro  Faith A. Cole 《Estuarine, Coastal and Shelf Science》2011,94(1):36-47

This study shows that spatially and temporally recurring benthic macrofauna-habitat patterns validate the ecological relevance of habitat types to benthic macrofauna and suggest they can serve as elements in ecological periodic tables of benthic macrofaunal usage. We discovered patterns across nine habitat types (intertidal eelgrass [Zostera marina], dwarf eelgrass [Zostera japonica], oyster [Crassostrea gigas] ground culture, burrowing mud shrimp [Upogebia pugettensis], burrowing ghost shrimp [Neotrypaea californiensis], shell, sand, mud, and subtidal) on a variety of benthic macrofaunal community state variables in Grays Harbor, Washington, USA and compared them to those in Willapa Bay, Washington, USA. There were nominal differences in benthic macrofaunal Bray-Curtis similarity between all the habitats investigated except eelgrass and oyster in both estuaries. Across-habitat patterns on mean benthic macrofaunal species richness, abundance, biomass, abundance of deposit, suspension and facultative feeders, a dominance and a diversity index for the five habitats common to both studies were the same on a rank measurement scale: eelgrass ≈ oyster > mud shrimp > ghost shrimp ≈ subtidal. The patterns for most of the habitats and benthic macrofaunal measures were the same on a ratio measurement scale.  相似文献   

Radionuclide (Cs and K) concentrations in the muscle of Baikal seal (Pusa sibirica) from Lake Baikal     

M. Udaka  T. Ikemoto  S. Takahashi  E.A. Petrov 《Marine pollution bulletin》2009,58(2):290-294

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Rainfall‐induced consolidation and sealing effects on soil erodibility during concentrated runoff for loess‐derived topsoils     

A. Knapen  J. Poesen  S. De Baets 《地球表面变化过程与地形》2008,33(3):444-458

Flume experiments simulating concentrated runoff were carried out on remolded silt loam soil samples (0·36 × 0·09 × 0·09 m³) to measure the effect of rainfall‐induced soil consolidation and soil surface sealing on soil erosion by concentrated flow for loess‐derived soils and to establish a relationship between soil erodibility and soil bulk density. Soil consolidation and sealing were simulated by successive simulated rainfall events (0–600 mm of cumulative rainfall) alternated by periods of drying. Soil detachment measurements were repeated for four different soil moisture contents (0·04, 0·14, 0·20 and 0·31 g g^?1). Whereas no effect of soil consolidation and sealing is observed for critical flow shear stress (τ_cr), soil erodibility (Kc) decreases exponentially with increasing cumulative rainfall depth. The erosion‐reducing effect of soil consolidation and sealing decreases with a decreasing soil moisture content prior to erosion due to slaking effects occurring during rapid wetting of the dry topsoil. After about 100 mm of rainfall, Kc attains its minimum value for all moisture conditions, corresponding to a reduction of about 70% compared with the initial Kc value for the moist soil samples and only a 10% reduction for the driest soil samples. The relationship estimating relative Kc values from soil moisture content and cumulative rainfall depth predicts Kc values measured on a gradually consolidating cropland field in the Belgian Loess Belt reasonably well (MEF = 0·54). Kc is also shown to decrease linearly with increasing soil bulk density for all moisture treatments, suggesting that the compaction of thalwegs where concentrated flow erosion often occurs might be an alternative soil erosion control measure in addition to grassed waterways and double drilling. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

铁山港湾水下动力地貌特征及其成因     

邓朝亮  黎广钊  刘敬合  梁文 《海洋科学进展》2004,22(2):170-176

探讨了铁山港湾的潮间浅滩、潮流冲刷深槽、潮流沙脊、水下拦门浅滩、水下岸坡和海底平原等水下动力地貌的形态特征及其成因,并结合沉积物的粒度、碎屑重矿物的分布特征,阐述了泥沙来源及运移趋势。  相似文献   

连云港西大堤工程后人工海湾内回淤强度的测算分析   总被引：3，自引：0，他引：3  

张华 《海洋工程》2000,18(1):70-74

本文重点研究了连云港西大堤工程后人工海湾内的回淤状况,得出以下结论：西大堤的封堵使人工海湾内的水动力和泥沙运动产生了明显的变化。但这只是工程后的局部调整,不会造成严重的淤积。由于湾内泥沙供应量的减少,连云港仍将维持冲淤相对平衡的状态。并且,本文以实测资料为依据,对两类主要的回淤预报公式进行了分析评价,证明了这两类公式的合理性和可靠性。  相似文献