Exploring composition and behaviour of fish fauna by in situ observations in the Bari Canyon (Southern Adriatic Sea,Central Mediterranean)          下载免费PDF全文

Gianfranco D'Onghia  Francesca Capezzuto  Angela Carluccio  Roberto Carlucci  Agnese Giove  Francesco Mastrototaro  Michele Panza  Letizia Sion  Angelo Tursi  Porzia Maiorano 《Marine Ecology》2015,36(3):541-556

Canyons play a fundamental role in enhancing the abundance and diversity of marine organisms through the transport of organic matter and food resources, the presence of complex physical habitats and the absence of trawl fishing. During four baited lander deployments carried out in the Bari Canyon (Southern Adriatic Sea, Central Mediterranean), at depths of 443–788 m, about 43 h of video records were taken, for a total of 619,200 video frames. A total of 12 benthopelagic fish species (five chondrichthyes and seven osteichthyes) were identified. The blackspot seabream (Pagellus bogaraveo) was the most often observed fish species. The depth of 787 m represents a new depth record for this fish in the Adriatic Sea. Groups of up to 40 individuals of P. bogaraveo were attracted to the bait and were shown in single frames. The individuals were observed both exploring the area and feeding actively on the bait. The European conger (Conger conger) was recorded at each deployment. Clear scavenger behaviour was also observed in this teleost fish and in the shark Etmopterus spinax. The shark species Centrophorus granulosus and Hexanchus griseus, which are considered ‘vulnerable’ on the published IUCN Mediterranean Regional Red List, were also recorded but, although attracted by the bait, they were never seen feeding on it. Other fish species, harvested on fishing grounds, such as Merluccius merluccius, Helicolenus dactylopterus and Polyprion americanus, were also recorded. This study represents the first in situ documentation, at very low impact, of the fish fauna in the Bari Canyon, providing new insights into its small scale distribution and behaviour, the first in situ direct observation of the variable feeding behaviour of P. bogaraveo and its gregarious habits, as well as indicating that this canyon could act as a refuge area for species that are vulnerable to fishing on the open slope.  相似文献   

AVAILABILITY OF PHOSPHORUS FROM SELECTED INORGANIC PHOSPHATES TO JUVENILE ABALONE,HALIOTIS DISCUS HANNAI INO.     

谭北平  麦康森  徐玮 《中国海洋湖沼学报》2002,20(2)

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渤海涟虫类和软体动物幼虫食性的观察   总被引：3，自引：0，他引：3  

杨纪明 《海洋科学》1998,22(6):36-38

根据消化道内食物分析结果得出：涟虫类、三叶针尾涟虫和驼背涟虫、瓣锶类后期幼虫和腹足类后期幼虫都营浮游植物食性,以硅藻类为主要食物。细长涟虫以星脐圆筛藻、未查明的圆筛藻和辐射圆筛藻为主要摄食对象;三叶针尾涟虫以舟形藻和新月菱形藻为主要摄食对象;驼背涟虫以辐射圆筛为主要摄食对象。鳃类后期幼虫以辐射圆筛藻和未查明的圆筛藻为主要摄食对象;腹足类后期幼虫以未查明的圆筛藻、辐射圆筛藻和中心圆筛藻为主要摄食对象  相似文献   

贝类养殖对海湾生态系统的影响   总被引：1，自引：0，他引：1  

季如宝  毛兴华  朱明远 《海洋科学进展》1998,(1)

本文描述了海水养殖贝类生态的主要特点,重点讨论了高密度贝类生物沉降过程以及对浮游植物的摄食控制等过程的生态效应。通过文献综述和个例分析,论述了贝类养殖对海湾生态系统的影响。本研究对贝类养殖业持续发展及沿海环境的保护均具有重要意义,文中还就今后的研究及方法学提出了建议。  相似文献   

Killer whales in South African waters—a review of their biology     

《African Journal of Marine Science》2013,35(2):171-186

The distribution, seasonality and schooling behaviour of killer whales Orcinus orca in South African waters have been investigated from 785 records compiled between 1963 and 2009, and their size, morphometrics, growth, reproduction, food and feeding behaviour described from the examination of 54 individuals, 36 of which were landed at the Durban whaling station between 1971 and 1975. Qualitatively, the species appears to be more frequently encountered offshore, where it forms small schools of generally less than six animals. Seasonality of occurrence is not marked, although circumstantial evidence indicates that some individuals migrate from higher latitudes. Males reach 8.81 m and females 7.9 m, with 16.2% of males exceeding the size of the largest female. Stomach content and observational data suggest that the species can be characterised locally as an opportunistic predator of megavertebrates, rather than as the fish-feeding ecotype previously described. A stranded adult male with extreme tooth wear that was 1.5–2 m shorter than other males of equivalent age may be representative of a separate ‘offshore’ ecotype. Apparent differences between features of the popu lation's life history and those of resident killer whales in the north-eastern Pacific might be attributed to either uncertainties in age determination using dentinal growth layer groups or sampling bias. The basis for the suggestion that killer whales in South African waters should be reclassified as Vulnerable (rather than Data Deficient) is challenged.  相似文献   

沙漠地区资源高精度三维地震勘探技术应用     

吴守华 《中国煤田地质》2006,18(3):57-59

内蒙古毛乌素沙漠西南边缘勘探区，地表大部分为固定、半周定沙丘．少部分为随季风流动的供状沙丘及新月型沙丘，地形起伏剧烈。该勘探区存在着检波器耦合难、实施变脱难、地震浒号屏蔽作用姓、心始记录面貌差、干扰波复杂、资料处理难度大等问题。为此采取了加长检波器尾锥、加大井深和药量、综合应用多种静校正技术以及与提高信噪比为主的资料处理流程等技术措施，经验证术措施采用合理，勘探成果准确可靠。  相似文献   

Grazing on microcystin-producing and microcystin-free phytoplankters by different filter-feeders: implications for lake restoration     

Luis M. Dionisio Pires  Babette M. Bontes  Larysa Samchyshyna  Jacco Jong  Ellen Van Donk  Bas W. Ibelings 《Aquatic Sciences - Research Across Boundaries》2007,69(4):534-543

  相似文献   

YZ-400型多功能液压钻机的研制          下载免费PDF全文

张培丰 《探矿工程》2002,(2):28-30

YZ－400型多功能液压钻机是以φ200－500mm大口径薄壁金刚石钻头钻取钢筋混凝土为主的液压动力头钻机，同时兼顾φ91和110mm金刚石岩心钻进。介绍了该机的技术参数、设计原则和结构特点。  相似文献   

南极鳕鱼食性的初步研究   总被引：1，自引：0，他引：1       下载免费PDF全文

黄凤鹏  吴宝铃 《极地研究》1992,4(4):51-54

对 1 98 8年 1 2月 2 5 - 2 6日在长城站附近海区采集的南极鳕鱼胃含物进行了初步分析。结果表明食物的主要种类有底栖动物 6种和钩虾多种 ,浮游动物 3种 ,海藻 8种。底栖动物占食物量的 5 2 .82 % ,其中帽贝占 1 0 .77% ,钩虾类占 3 3 .78% ;浮游动物占 6 .74% ,其中磷虾占 5 .47% ;海藻占 3 5 .49% ,其中紫菜占 6 .3 5 % ,倒卵银杏藻占 1 8.96 %。鱼的体重与体长相关显著 ,相关系数是 0 .96。分析结果反映了南极鳕鱼的食物来源主要是底栖动物和海藻  相似文献   

CD-3型岩心钻机的研制          下载免费PDF全文

宋振波  李建华  高富丽 《探矿工程》1997,(1):4-7

介绍了ＣＤ－３型岩心钻机研制情况，技术参数，主要特点及型式检验，生产试验和鉴定情况。  相似文献