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1.
【目的】调查了解镇江豚类保护区鱼类资源状况,丰富鱼类资源本底数据。【方法】于2013、2016和2019年,分别开展3次渔业资源调查,对该区域鱼类种类组成、优势种、体型大小及群落多样性进行统计分析。【结果】共记录鱼类68种属于7目13科47属;鲤形目(Cypriniformes)鱼类种类占比较为稳定,鲇形目(Siluriformes)鱼类资源量有下降趋势,鲈形目(Siluriformes)鱼类种类占比上升明显;不同年份优势种替代较为明显;2016年的物种丰富度指数和多样性指数最高,分别为6.528、3.026。【结论】保护区鱼类资源较为丰富,但不同年份鱼类群落变化较为明显,渔业资源面临小型化趋势。  相似文献   
2.
维生素D(VD)是一类具有抗佝偻病作用的类固醇激素,其中维生素D3(VD3)是VD在动物体内的主要存在形式。作为生命活动必不可少的一类物质,VD发挥着广泛且重要的生理学作用。VD在动物体内的代谢过程及相关的代谢酶具有较高的进化保守性,同时也受到多种因素的调控影响。由于鱼类在生活环境方面与陆生脊椎动物存在显著差异,VD在鱼类中的合成代谢及生理功能与高等动物也存在一定的区别。本文主要概述了鱼类VD3的主要来源以及需求量的研究,总结了近年来鱼类维生素D受体(VDR)、VD3代谢调控及其生理功能的研究进展,比较了鱼类和陆生高等动物在VD来源、代谢以及VDR等方面的差异,并对水生动物VD的未来研究方向进行了展望。  相似文献   
3.
Recent studies have suggested that poikilothermic animals, such as fish, may represent a previously overlooked source of the faecal indicator bacteria (FIB) used for the assessment of water quality. However, quantitative studies of FIB in poikilotherms are scarce. We investigated the presence of FIB in the faeces of five freshwater fish species. E. coli and enterococci were detected in 71 and 76% of faecal samples, respectively. Concentrations were highly variable, with maximum concentrations (2.1?×?104 E. coli and 1.3?×?106 enterococci per gram of faecal material) up to four orders of magnitude higher than present in the water column. FIB were not detected in faecal samples from marine fish. Our findings suggest that FIB ingested from the environment may be capable of replication within the fish gut, making fish a potential source and transport mechanism for FIB in New Zealand freshwaters. This may have implications for water quality monitoring.  相似文献   
4.
本文以印尼北苏拉威西东部的潟湖为对象,研究了热带海草床鱼类群落的种类组成和时空变化。研究发现当地鱼类的香农-威纳指数在1.57-3.69之间多样性相对较高。在科水平,天竺鲷科的丰度(8.27 ind./(100 m2))和生物量(28.49 g/(100 m2))最高。在物种水平,侧带天竺鲷(Apogon lateralis)的丰度最高,环纹圆天竺鲷(Sphaeramia orbicularis)的生物量最大。对于物种的空间变化,潟湖湖顶、湖中和湖口首先聚类在一起,这可能是由于基质类型引起的。干季和湿季的鱼类种类、丰度和生物量均比转换季高,这可能是由较强的季风造成的,强季风为鱼类提供了更适宜的环境和食物。93.1%的鱼类的最大体长小于它们的性成熟体长,暗示了海草床是很多鱼类的育幼场。因此,保护海草床对渔业和资源的可持续利用至关重要。  相似文献   
5.
The larval stage of fishes is critical in determining their dispersal, survival and recruitment, but little is known of the larval behaviours and tolerances of amphidromous fishes, particularly in New Zealand. We report the results of a series of observational and experimental studies on bluegill bully (Gobiomorphus hubbsi), including spawning sites and behaviours, larval characteristics at hatch, phototactic responses of larvae, and larval survival at different salinity levels. Spawning primarily occurred in the lower reaches of the river, and larvae from different nests exhibited marked differences in, and trade-offs between, larval characteristics at hatch, potentially affecting larval success. Larvae were positively phototactic to intense light, an unexpected result based on diel drift patterns and international research. Finally, larvae exhibited markedly higher survival rates when reared at intermediate salinities compared to freshwater or seawater, suggesting estuaries may play an important role as nursery grounds for bluegill bully and other amphidromous fish.  相似文献   
6.
Juveniles of the Cape white seabream Diplodus capensis were observed cleaning adult conspecifics in a large tidepool off Sodwana Bay, South Africa. Although nine other tropical fish species were present and interacted with a nearby pair of Labroides cleaner wrasses, only adults of D. capensis posed for and were cleaned by the D. capensis juveniles. Such cleaning interactions have not been reported previously for this species or among marine fishes off South Africa, and thus add to the growing list of facultative cleaners globally.  相似文献   
7.
为探究洱海湖滨区环境因子与蜻蜓物种多样性之间的关系,2014年5月至2017年5月对洱海10个样点进行实地调查,记录植物20科46种,共采集蜻蜓11科22属28种1448个体,并对环境因子与蜻蜓多样性进行相关性分析.结果表明蜻蜓成虫多样性与植被丰富度、湿生植被覆盖度、挺水植被覆盖度和沉水植被覆盖度均呈正相关,与浮水植物覆盖度和人为干扰程度呈负相关;稚虫多样性与湖底底质和水体溶解氧呈正相关,并对结果进行了讨论.研究结果给洱海蜻蜓栖息地的保护及湖滨缓冲带生态修复提供了有益的参考和数据支持.  相似文献   
8.
为研究矿山开采及修复过程中如何开展生物多样性管理,本文借鉴IUCN(世界自然保护联盟)发布的《矿山生物多样性管理系列指南》成果,将相关理论和方法应用到广东大宝山矿生态修复实践中。文章在介绍IUCN的“综合生物多样性管理体系”方法主要内容的基础上,将其作为大宝山矿实施生态修复依据,阐述了该管理体系在矿山生态修复工程中的应用,并结合广东大宝山矿的实际情况,提出了大宝山矿生物多样性管理的保护与修复框架,包括全周期的生物多样性管理手段,重点阐述大宝山矿生物多样性调查与监测、评价、保护与受损控制及恢复的技术方案,最后分析了对中国矿山生物多样性保护和修复的启示,IUCN矿山生物多样性管理系列指南对于指导我国矿山生态修复具有重要作用。  相似文献   
9.
ABSTRACT

The Australian government’s proposal to expand the Snowy Hydro Scheme to include a second pumped hydro energy storage (PHES) system, and support for feasibility studies for PHES in Tasmania, offer an opportunity to incorporate more intermittent renewable energy generation into the National Energy Market. However, the infrastructure construction required for PHES expansion may have negative effects for biodiversity in subalpine and alpine areas. To identify the potential effects of PHES on biodiversity in Kosciuszko National Park (KNP), this systematic literature review assesses: (i) the key environmental disturbances likely to arise from PHES construction; and (ii) the specific impacts of these construction processes on biodiversity in subalpine and alpine environments. We find that the effects of PHES construction-related disturbances are likely to be negative for subalpine and alpine biodiversity, with impacts including the proliferation of exotic flora, habitat loss resulting from vegetation clearing, altered landscape hydrology and reduced water quality. Management recommendations to limit these impacts are provided and further research is recommended to assess: (i) the effects of PHES on fish populations in alpine reservoirs; (ii) the utility of spoil as artificial habitat for endemic fauna; and (iii) the chemical and physical impacts of spoil dumping in alpine reservoirs.  相似文献   
10.
The biodiversity hotspot region of the Eastern Himalayas consists of a vast freshwater network enriched with species diversity. Many small-scale torrential rivers and water reaches contribute to the species pool of all the major rivers by converging downstream. These reaches are most likely to be degraded at a faster rate as compared to the large-scale rivers following an increased rate of urbanization, habitat alterations, and changing climatic conditions. Therefore, this study aims to explore River Murti, which is a representative small scale river system characterized by a large altitudinal gradient and a diverse watershed area. Ichthyofaunal diversity (i.e., diversity, evenness & richness) and 21 environmental variables are measured through a tri-seasonal sampling effort conducted along 14 selected locations. A total of 41 fish species (including species belonging to 4 Near Threatened, 8 Vulnerable, and 1 Endangered) are found inhabiting this river. Ichthyofaunal assemblage is found to be primarily modulated by habitat diversity and landscape variables. Three Aquatic Ecological Systems (AES) have been identified along this river in a top-down approach based on recorded environmental variables. We have calculated an observed/expected ratio for each diversity indices along 14 locations based on predicted temporal variability using boosted regression (BRT) models. The evaluation of diversity status has been kept at 0.5 to account for a 50% loss or deviation from observed (O/E50). This evaluation has been successfully used to delineate AES1 with majorly “Impaired” status and thus ensures its importance in terms of species conservation. Our study indicates the contribution of 11 major environmental drivers modulating the species assemblage patterns in these AES. Amongst them, altitude, substrate coarseness, river morphology, and shelter availability are strongly associated with species diversity as per the BRT models. These underlying factors are also correlated with “basin pressure,” suggesting that anthropogenic disturbances, as well as the changing climate, might play an important role in the gradual change in environmental conditions, which in turn could cause a shift in species assemblage structure.  相似文献   
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