Fine-scale distribution of sardine (Sardina pilchardus) eggs and adults during a spawning event   总被引：2，自引：0，他引：2  

Juan Zwolinski  Evan Mason  Paulo B. Oliveira  Yorgos Stratoudakis 《Journal of Sea Research》2006,56(4):294-304

High-resolution acoustic and ichtyoplankton sampling with a ‘continuous under-way fish egg sampler (CUFES)’ was performed in two regions of approximately 100 square nautical miles off southern Iberian Peninsula, with the aim of studying the small scale distribution of sardine (Sardina pilchardus) adults and eggs during a spawning event. Very dense patches (246 eggs m^− 3) of recently spawned eggs with dimensions (up to 3 nautical miles wide) significantly larger than daytime sardine schools were present in both regions. Egg staging and ageing showed very little intra-sample variation, indicating a synchronous spawning period at dusk. The internal structure of the patches evaluated by variography showed very low internal variability, as if they consisted of a single unit. This hypothesis is confirmed by the acoustic finding of large sardine shoals with similar dimensions to those of the patches after sunset and throughout the night. During that period, adults were found near or in contact with the bottom, suggesting that spawning occurred at depth. A distinct patch of older eggs was found in both areas, but with a few nautical miles of horizontal separation. Their characteristics (a larger area, lower egg densities and a more irregular shape) indicate that these patches were exposed to dispersion and ‘stirring’ by physical forces, reshaping their initial appearance, while mesoscale water circulation could have displaced the core of the patches away by several kilometres within a day.  相似文献   

Preparation,Characterization of a Novel Chelating Resin Functionalized with o‐Hydroxybenzamide and Its Application for Preconcentration of Trace Metal Ions     

Aminul Islam  Akil Ahmad  Mohammad Asaduddin Laskar 《洁净——土壤、空气、水》2012,40(1):54-65

A stable extractor of metal ions was synthesized through azo linking of o‐hydroxybenzamide (HBAM) with Amberlite XAD‐4 (AXAD‐4) and was characterized by elemental analyses, IR spectral, and thermal studies. Its water regain value and hydrogen ion capacity were found to be 12.93 and 7.68 mmol g^?1, respectively. The optimum pH range (with the half‐loading time [min], t_1/2) for Cu(II), Cr(III), Ni(II), Co(II), Zn(II), and Pb(II) ions were 2.0–4.0 (5.5), 2.0–4.0 (7.0), 2.0–4.0 (8.0), 4.0–6.0 (9.0), 4.0–6.0 (12.0), and 2.0–4.0 (15.0), respectively. Comparison of breakthrough and overall capacities of the metals ascertains the high degree of column utilization (>70%). The overall sorption capacities for Cu(II), Cr(III), Ni(II), Co(II), Zn(II), and Pb(II) ions were found to be 0.29, 0.22, 0.20, 0.16, 0.13, and 0.11 mmol g^?1 with the corresponding preconcentration factor of 400, 380, 380, 360, 320, and 320, respectively. The limit of preconcentration was in the range of 5.0–6.3 ng mL^?1. The detection limit for Cu(II), Cr(III), Ni(II), Co(II), Zn(II), and Pb(II) were found to be 0.39, 0.49, 0.42, 0.59, 0.71, and 1.10 ng mL^?1, respectively. The AXAD‐4‐HBAM has been successfully applied for the analysis of natural water, multivitamin formulation, infant milk substitute, hydrogenated oil, urine, and fish.  相似文献   

Brominated flame retardants and organochlorine contaminants in winter flounder, harp and hooded seals, and North Atlantic right whales from the Northwest Atlantic Ocean     

Eric W. Montie  Robert J. Letcher  Michael J. Moore  Mark E. Hahn 《Marine pollution bulletin》2010,60(8):1160-1169

Various brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and current-use, non-PBDE BFRs, as well as organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), were measured in winter flounder, harp and hooded seals, and North Atlantic right whales from the Eastern United States and Canada. The concentrations of PBDEs in winter flounder and right whales were similar in magnitude to the levels of PCBs, which was unlike the pattern observed in seals. In these marine mammals, the levels of PBDEs were orders of magnitude lower than the levels of OCs and PCBs detected. Evidence existed for the accumulation of methoxylated (MeO)-PBDEs of natural origin in seals and right whales. Current-use, non-PBDE BFRs (including hexabromocyclododecane, pentabromoethylbenzene, hexabromobenzene, and pentabromotoluene) were detected in winter flounder and marine mammals. Future research should focus on monitoring PBDEs, current-use, non-PBDE BFRs, and MeO-BDEs of natural origin in marine organisms from Massachusetts and Cape Cod Bays.  相似文献   

Post World War II orcharding creates present day DDT-problems in The Sørfjord (Western Norway) - A case study     

Anders Ruus  Norman W. Green  Carl Einar Amundsen  Jens Skei 《Marine pollution bulletin》2010,60(10):1856-1861

The Sørfjord has a long history of agriculture and industry, and environmental monitoring has been conducted for decades, comprising analyses of contaminants in mussel, fish and sediments. DDT was used as an insecticide in orchards surrounding the fjord between World War II and 1970. Since the early 1990s, elevated concentrations of DDT were found in mussels and fish. Unexpectedly, DDT-concentrations increased towards present day, despite the discontinuation of use. The highest concentrations in mussels (in 2006) corresponded to about two orders of magnitude higher than background. Analyses of sediment core sections also indicated increased input towards present day. Shifts in climatic parameters, as well as increased amounts of soil dissolved organic carbon following a decline in atmospheric sulphate deposition may have contributed to this phenomenon. We warrant the need for increased knowledge of the effects of alterations in variables acting regionally and globally on the disposition of contaminants in ecosystems.  相似文献   

Biochemical Alteration in the Labeo rohita Tissues Following Exposure to the Effluent Generated during Extraction of Metals from Polymetallic Sea Nodules          下载免费PDF全文

Huma Vaseem  Tarun K. Banerjee 《洁净——土壤、空气、水》2014,42(8):1060-1065

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In-situ partitioning and bioconcentration of polycyclic aromatic hydrocarbons among water,suspended particulate matter,and fish in the Dongjiang and Pearl Rivers and the Pearl River Estuary,China   总被引：1，自引：0，他引：1  

Haiyan Li  Lei Lu  Wen Huang  Juan Yang  Yong Ran 《Marine pollution bulletin》2014

The partitioning and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), and fish samples from the Dongjiang River (DR), Pearl River (PR), and the Pearl River Estuary (PRE) were examined. Although PAHs are much lower in PRE than in DR or PR, PAHs in some fish species are significantly higher in PRE than in DR or PR. Aqueous or particulate PAHs respectively show significant correlations with dissolved organic carbon, particulate organic matter, and chlorophyll a, suggesting that biological pumping effect regulates their distribution. The in situ partitioning coefficients (log K_oc) for PAHs are one order magnitude higher than the empirical log K_oc–log K_ow correlation. The bioconcentration factor (BCF) is slightly higher for the marine fish than for the freshwater fish. The above phenomena indicate that BCF may vary due to the diversity of fish species, feeding habits, and metabolism of PAHs in fish.  相似文献   

Fish distribution patterns and habitat availability in lakes Moreno Este and Moreno Oeste,Patagonia, Argentina     

《Limnologica》2014

Andean Patagonian lakes are ultraoligotrophic and deep, have simple food webs and low fish diversity and abundance. In this work the distributional abundance data of fish was studied in two interconnected Andean Patagonian lakes with varying proportions of contrasting habitat types. Hydroacoustic data (120 kHz) were used to analyze fish abundance and habitat use during the mixis and stratification periods. Three types of habitat (near shore, surface pelagic and deep pelagic) and two groups of fish, based on size (Big Fish >12 cm total length and Fish Larvae and Small Fish <12 cm total length) were defined. The distribution of both fish groups in these lakes revealed differences in habitat use for each lake and period. Fish group abundance was related to the availability of habitat types, according to the morphology of each lake. The Big Fish group showed preference for the near shore habitat during lake stratification and always appeared as individual targets. The Fish Larvae and Small Fish group used mainly the pelagic habitat during mixis, where they formed dense sound scattering layers. However, during lake stratification many individual targets from this group were found both in pelagic and near shore habitats, which would seem to indicate a change in distributional behavior. This is possibly associated with niche changes in the Galaxiids (Galaxias spp), a key component of Northern Patagonian lake food webs. Lakes like Moreno Oeste, which are morphologically and structurally more complex, could have more diverse fish ensembles with higher abundances. In contrast, lakes of simple morphology with low development of near shore habitats and ample deep zones, like Lake Moreno Este, could present lower Big Fish abundance. The contrasting habitat availability between lakes accounts for the abundances and distribution patterns of each fish group. While in these lakes fish assemblage species composition could depends on the environmental filter, the particular structure of a fish assemblage in terms of the proportional abundances of species depends on proportional habitat type availability. We can speculate that in Andean Patagonian lakes Galaxiids mediate a habitat coupling process critical for the transfer of energy and matter in oligotrophic lakes. We may also consider that the Small Puyen in this type of lake is a keystone prey species that relieves predation pressure on other potential prey. The existence of deep pelagic habitats in numerous deep lakes in the Northern Patagonian Andean region provides not only daytime refuge for Galaxiids, which allows them to maintain their high numbers in the lakes, but could also, in the long term, act as a Galaxiid source for other water bodies.  相似文献   

In-stream water quality,invertebrate and fish community health across a gradient of dairy farming prevalence in a New Zealand river catchment     

《Limnologica》2016

Dairying is an intensive form of agriculture influencing stream ecosystems worldwide via increased levels of nutrients, deposited fine sediment and other contaminants. However, it is not fully understood how dairy farming affects food supply for stream fish. We investigated relationships between dairy farming prevalence in the catchments of nine tributaries of a New Zealand river (0% to 79% of the catchment area) and fish and invertebrate communities. Streams were sampled four times at monthly intervals for brown trout density, fitness/growth-related trout response variables, native fish density, invertebrate community metrics as well as physical and chemical water quality variables. Densities of both brown trout and native fish declined as dairying increased, with no trout found in streams where dairy farms covered more than 50% of the catchment area. Increasing dairy farming prevalence was also associated with higher in-stream levels of dissolved nutrients and deposited fine sediment. These findings suggest that increasing the extent of dairy farming in New Zealand based on practices at the time of sampling results in less abundant and diverse fish communities.  相似文献   

Predicting fish species richness and assemblages with climatic,geographic and morphometric factors: A broad-scale study in Chinese lakes     

《Limnologica》2015

The present study was designed to investigate the relative importance of climatic (temperature and precipitation), geographic (altitude) and morphometric (lake area) factors in predicting fish species richness and assemblages in Chinese lakes at a large spatial scale. Two recursive partitioning tree-based approaches: Classification and Regression Trees (CARTs) and Multivariate Regression Trees (MRTs) were employed to generate predictive models respectively. Six fish assemblages were thus defined from the MRT model. The results indicated that lake altitude was the main determinant for predicting fish assemblages in Chinese lakes (30.43%), followed by precipitation of the driest month (10.47%), temperature annual range (3.62%) and annual mean temperature (3.15%). Validated CART model implied that precipitation of driest month, maximum temperature of warmest month and lake area were the main predictors in determining fish species richness patterns. Overall, our results indicated that the altitudinal extent and range of climatic variation was sufficient to overshadow the area effect in predicting fish species richness and assemblages in Chinese lakes. At the macroecological scale, the effect of temperature and precipitation on fish richness and assemblages also suggests future changes in fish diversity as a consequence of climate change.  相似文献   

The Age,Growth, Fecundity of Carassius auratus in the Guohe River of Guoyang County          下载免费PDF全文

An Wan  Shijin Yu  Jin Hu  Yun Wan  Ying Wei  Ming Zhong  Hongfei Yang  Yunzhi Yan 《洁净——土壤、空气、水》2015,43(5):676-682

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