山东半岛南部沿岸中国对虾放流数量对秋汛产量的影响     

信敬福 《水产科学》1999,18(6):7-9

根据１９８３～１９９８年山东半岛南部沿海对虾放流增殖结果,对秋汛对虾产量与放流数量之间的关系进行了研究。结果表明：秋汛对虾产量随放流数量的增加而增加,二者呈Ｙ＝３６３．７＋１２６．４Ｘ相关关系（ｒ＝０．９１８）。  相似文献   

对船艇部队码头基地防护林建设的几点思考     

魏丹军  胡盼 《林业勘查设计》2006,(4):33-34

从6个方面分析论述了沿海防护林建设中存在的问题,呼吁性提出解决诸多不利于沿海防护林发展的建议。  相似文献   

Optimal dietary protein requirement for juvenile ivory shell, Babylonia areolate     

Jian-Bin Zhou  Qi-Cun Zhou  Shu-Yan Chi  Qi-Hui Yang  Chu-Wu Liu 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):186-192

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile ivory shell reared in indoor aerated aquaria. Six isoenergetic experimental diets using fish meal, casein and gelatin as protein sources were formulated to contain graded levels of protein (27, 33, 38, 43, 49 and 54% of dry diet, respectively). Triplicate groups of 40 shells (average weight 93.50 ± 1.70 mg) were stocked in 120-l tanks and fed to apparent satiation twice daily for 8 weeks. The results showed that the growth performance and feed utilization were significantly affected by dietary protein level (P < 0.05). Maximum weight gain, mean protein gain, specific growth rate and soft body to shell ratio occurred at 43% dietary protein level (P < 0.05). There were significant differences in protein, lipid, moisture and ash content in soft body; except that ash content in shell was not significantly affected by dietary protein level. Pepsin activity in soft body tissue significantly increased with dietary protein level up to 43%, and trypsin-like enzyme activity increased with dietary protein level up to 49%. However, lipase activity in soft body decreased with increasing dietary protein level. However, no significant differences (P < 0.05) in survival, calcium, phosphorus concentration in the shell and soft body were found among dietary treatments. Quadratic regression analysis of weight gain against dietary protein level indicated that the optimal dietary protein requirement for maximum growth and feed utilization of juvenile ivory shell is 45% of dry diet.  相似文献   

Behavioural interactions of seabirds with suspended mussel longlines     

Daphne Roycroft  Thomas C. Kelly  Lesley J. Lewis 《Aquaculture International》2007,15(1):25-36

Increased abundances of a number of seabird species have been found in areas of mussel longline aquaculture (compared to control sites) in a recent study at Bantry Bay, southwest Ireland. The aim of this study was to investigate whether this form of mussel aquaculture also affects the activity budgets and foraging behaviour of these seabirds. Scan-sampling was used to compare seabird activity budgets between three areas of mussel longline aquaculture and three control sites. Foraging activities of Great-Northern Divers Gavia immer, an Annex 1 species under the Euopean Union's Birds Directive, were also compared between sites using focal sampling. The behaviour of gulls (Larus sp.), Cormorants Phalacrocorax carbo, Shags Phalacrocorax aristotelis and Great-Northern Divers (but not auks, Alcidae) differed significantly between areas of mussel aquaculture and control sites in this study. Mussel suspension buoys were heavily utilized by gulls, cormorants and shags as safe perching platforms for preening activities. Gulls also fed extensively on epifauna attached to the buoys. Great-Northern Divers spent more time snorkelling (head submerged in search of food) in mussel sites than in the control sites, however dive duration and visible foraging success rates did not differ significantly between sites. Overall, the environmental impact of mussel suspension culture appears to be positive or neutral on marine bird species occurring at this study site.  相似文献   

Megaparks for metapopulations: Addressing the causes of locally high elephant numbers in southern Africa     

Rudi J. van Aarde  Tim P. Jackson 《Biological conservation》2007,134(3):289-297

Conservation management options for southern African elephants range from local to regional scales. Here we review these options and argue in favour of actions that will deal with the causes rather than symptoms of elephant numbers that are locally high. Metapopulation theory ensures population persistence, while our approach extends this in order to stabilise elephant numbers regionally. By allowing for the development and maintenance of regional sinks, we may also limit numbers in sources. This application of the metapopulation metaphor is a powerful ecological platform from which to manage elephant numbers and impact through southern Africa. Our approach engages the causes of the apparently high abundance of elephants in parts of southern Africa. It moves away from the practice of dealing only with numbers (symptoms) when managing the impact of elephants on other species. While providing an ecological basis for the development of elephant management options, this needs to be melded with social, political and economic realities through southern Africa. In this regard we are encouraged by the ongoing development of several Transfrontier Conservation programmes and Peace Parks across the region.  相似文献   

Freshwater snail distribution related to environmental factors in Banco National Park,an urban reserve in the Ivory Coast (West Africa)     

《African Zoology》2013,48(1):160-168

Freshwater snails and environmental variables were studied at seven stations along the Banco River (Ivory Coast;West Africa) from March to October 2008. Two species (Physa marmorata (Physidae) and Bulinus forskalii (Planorbidae) were recorded only at one sampling site. This station which received domestic sewage from the neighbouring cities was characterized by the highest conductivity and pH and the lowest values of dissolved oxygen. Multiple stepwise regression analysis showed that snail densities were probably influenced by conductivity, dissolved oxygen, pH, and canopy cover. Also, snail dynamics showed a seasonal pattern, with peak population densities and recruitment of young generations during rainy periods. This study highlighted the impacts of sewage on snail diversity and distribution in the Banco River. Overall, this paper strengthens the viewpoint that the Banco River management should be implemented to lessen the impact of anthropogenic activities on the ecology of the Banco National Park.  相似文献   

Relationships of dead wood patterns with biophysical characteristics and ownership according to scale in Coastal Oregon,USA   总被引：1，自引：0，他引：1  

Rebecca S. H. Kennedy  Thomas A. Spies  Matthew J. Gregory 《Landscape Ecology》2008,23(1):55-68

Dead wood patterns and dynamics vary with biophysical factors, disturbance history, ownership, and management practices; the relative importance of these factors is poorly understood, especially at landscape to regional scales. This study examined current dead wood amounts in the Coastal Province of Oregon, USA, at multiple spatial scales. Objectives were to: (1) describe current regional amounts of several characteristics of dead wood; (2) compare dead wood amounts across ownerships; (3) determine the relative importance, according to spatial scale, of biophysical and ownership characteristics, to regional dead wood abundance. Dead wood plot data were evaluated with respect to explanatory variables at four spatial scales of resolution: plots, subwatersheds, watersheds and subbasins. The relationships of dead wood characteristics with biophysical attributes and ownership were diverse and scale-specific. Region-wide dead wood abundance and types varied among ownerships, with public lands typically having higher amounts of dead wood and more large dead wood than private lands. Regression analysis of total dead wood volume indicated that ownership was important at the subbasin scale. Growing season moisture stress was important at plot, subwatershed, and watershed scales. Topography was important at the two coarser scales. Multivariate analysis of dead wood gradients showed that ownership was important at all scales, topography at the subbasin scale, historical vegetation at watershed and subbasin scales, and current vegetation at plot and subwatershed scales. Management for dead wood and related biodiversity at watershed to landscape scales should consider the distinct dynamics of snags and logs, the importance of historical effects, and the relevance of ownership patterns.  相似文献   

沿海滩涂耐盐米草稻高产栽培技术     

陈启康  陈博  陆惠兰  周慧  梅治平 《农业科学与技术》2016,(8)

针对沿海滩涂盐碱地的特点,通过实施水土资源利用、耕作改良、配套水系建设、种子选择及处理、水直播、苗床育秧、大田移栽、除草、肥水管理、病虫害防治等技术探索实践,使得耐盐米草稻稻谷产量可达5 925～8 280kg/hm2,可为沿海滩涂种植米草稻提供科学栽培技术依据.  相似文献   

全球气候变化对浙江沿海红树林的影响   总被引：2，自引：0，他引：2  

龚婕  豫秦  少波 《安徽农业科学》2009,37(20):9742-9744

浙江是我国人工引种红树林的最北界。从3个方面论证了全球气候变化对浙江沿海红树林的影响,并在此基础上阐述了浙江省红树林的发展策略。  相似文献   

沿海滩涂的生物学综合利用     

张君  张边江 《河北农业科学》2009,13(7):64-65

阐述了滩涂的形成、分布及开发利用现状,介绍了滩涂生物学开发的主要途径,并展望了我国滩涂生物学开发利用的发展方向。  相似文献