scholarly journals Parasitic monogenoideans of Sciades herzbergii as bioindicators of environmental quality in amazonian estuarines ecosystems

Author(s):  
Kelle de Nazaré Cunha ◽  
Marcus Vinicius Domingues ◽  
Lucas Daniel da Silva Cunha ◽  
Zélia Maria Pimentel Nunes

Abstract This study evaluated the use of gill parasitic monogenoideans from Sciades herzbergii (Siluriformes: Ariidae) as bioindicators of environmental quality in Amazonian estuarine ecosystems. Fish were caught in the tidal channels in an impacted area - IA, near the port of São Luís and a reference area - RA, in the Caeté estuary, Bragança. The influence of the capture site and seasonality on parasite abundance, environmental variables and biometric data of hosts were verified. A total of 416 S. herzbergii specimens were analyzed. The weight and total length of fish from the RA were greater than those of the IA. The relative condition factor was influenced by seasonality. A total of 4,265 monogenoidean specimens from the following species were identified: Chauhanellus boegeri, C. susamlimae, C. velum, Calceostomella herzbergii and Dactylogyridae gen. sp. The seasonal mean parasitic abundance of C. susamlimae was significantly different, with the highest values recorded during the dry season. The mean abundance of C. herzbergii was influenced by seasonality and by the capture site. During the rainy period, the parasite indices in the RA were higher than those of IA. C. herzbergii is a bioindicator sensitive to low water quality, especially in relation to water turbidity in Amazon estuaries.

Parasitology ◽  
1984 ◽  
Vol 89 (2) ◽  
pp. 209-220 ◽  
Author(s):  
C. R. Kennedy

SummaryFollowing recent suggestions that a peaked host age–parasite abundance curve, concomitant with a decline in the degree of dispersion of parasites in the older age classes of hosts, can provide evidence of parasite-induced host mortality, the changes in mean abundance and over-dispersion of metacercarial stages of Diplostomum spathaceum, D. gasterostei, Tylodelphys clavata and T. podicipina in relation to fish age were studied in a field locality. The mean parasite burden of D. spathaceum, D. gasterostei and T. clavata increased with host age and the maximum mean burden was found in the oldest hosts. The variance to mean ratio also increased in D. gasterostei, but decreased in the oldest hosts in D. spathaceum and T. clavata. It is concluded that this decrease could be due to parasite-induced host mortality but could equally be due to death of parasites within the host or to changes in infection rate or could be a reflection of the small sample size of the oldest fish. The mean burden of T. podicipina declined gradually with host age, but the variance to mean ratio remained constant and it is concluded that this could be explained by death of the parasites within the host. None of these data or data from other localities provided clear and unambiguous evidence of host mortality induced by heavy infections of any of the four species, although they are consistent with such mortality and do not refute such a possibility. It is concluded that it may be just as difficult to detect and unequivocally demonstrate parasite-induced host mortality in metacercarial digenean–fish host systems as in any other parasite–host systems.


1996 ◽  
Vol 63 (2) ◽  
pp. 315-327 ◽  
Author(s):  
P. J. Goddard ◽  
I. J. Gordon ◽  
W. J. Hamilton

AbstractWild red deer (Cervus elaphus) hinds were subjected to one of five post-capture management strategies during the period from capture in late pregnancy in March, until weaning in September. The treatments were: remained enclosed at the capture site; relocated to a remote site; relocated to a conventional deer farm on improved pasture; relocated to a conventional deer farm and grazed with farmed hinds; housed prior to calving on a conventional deer farm site. For a further year, all hinds were managed under conventional deer farm conditions. There was considerable evidence, based on mortality and behaviour, to suggest that initial housing of the hinds following capture compromised their welfare. Deaths of hinds (seven out of 20) occurred in this group, associated with bullying during the housed period. Hinds on this treatment also showed a higher frequency of aggressive interactions compared with the groups directly moved to the deer farm (11% v. 2% respectively of scans conducted at 10-min intervals over 6h; P < 0·001) and a reduced level of lying behaviour (15% v. 34 to 47% of scans; P < 0·001) during the gestation period. Similarly, during the calving period, this group lay the least (27% v. 43 to 72% of scans; P < 0·001) and the mean number of interactions between hinds reached 11·7 compared with 1·5 to 4·9 (F < 0·001) in the other groups over a continuous 6-h recording period. The two groups of hinds relocated directly onto sown swards were generally similar to one another in terms of behaviour and performance. However, the group mixed with farmed hinds suffered from considerable calf losses in year 1 due to disease (four out of 12). Losses of hinds over winter in year 1 (nine out of 90) occurred principally amongst those animals which had not become habituated to human presence or supplementary feeding in the summer, i.e. groups remaining enclosed at the capture site or relocated to a remote site. When all hinds were treated similarly in year 2 the hinds from these same two groups, together with those initially housed indoors, showed more hind-hind interactions overall than the two groups located directly onto the deer farm (7·2 v. 3·1 interactions per hind over a 4-h period; P < 0·02) and it is suggested that these hinds had not yet adapted to their new environment. An ACTH stimulation test conducted during year 2 supported the view that the two groups of hinds most recently introduced into the managed system were subject to a chronic stressor at the time of testing, since administration of ACTH did not elicit a significant increase in plasma cortisol concentrations (mean values pre- and post-ACTH 188 and 217 nmol/l respectively). In contrast, the mean plasma cortisol concentrations of the two groups managed under extensive farm conditions from the outset, showed a significant rise (pre- and post-ACTH, 261 and 376 nmol/l respectively; P < 0·01). From this it is concluded that their adaptation to the farm environment had already occurred. The live-weight gains of the wild hinds calves (229 g/day) on the improved pastures in the 1st year of the study were below that for farmed hinds calves (282 g/day; P < 0·05), suggesting that they were not habituated to the management system. However, by the end of year 2 animal performance was comparable with that of farmed hinds and calf growth rates reached 276 g/day. Thus while housing wild red deer immediately after capture is associated with poor welfare, analysis of behaviour, adrenal response and animal production over a longer period suggests that by the end of the study few important differences remained between the groups.


2001 ◽  
Vol 440 ◽  
pp. 49-74 ◽  
Author(s):  
G. SEMINARA ◽  
M. TUBINO

We investigate the basic mechanism whereby bars form in tidal channels or estuaries. The channel is assumed to be long enough to allow neglect of the effects of end conditions on the process of bar formation. In this respect, the object of the present analysis differs from that of Schuttelaars & de Swart (1999) who considered bars of length scaling with the finite length of the tidal channel. The channel bottom is assumed to be cohesionless and consisting of uniform sediments. Bars are shown to arise from a mechanism of instability of the erodible bed subject to the propagation of a tidal wave. Sediment is assumed to be transported both as bedload and as suspended load. A fully three-dimensional model is employed both for the hydrodynamics and for sediment transport. At the leading order of approximation considered, the effects of channel convergence, local inertia and Coriolis forces on bar instability are shown to be negligible. Unlike fluvial free bars, in the absence of mean currents tidal free bars are found to be non-migrating features (in the mean). Instability arises for large enough values of the mean width to depth ratio of the channel, for given mean values of the Shields parameter and of the relative channel roughness. The role of suspended load is such as to stabilize bars in the large-wavenumber range and destabilize them for small wavenumbers. Hence, for large values of the mean Shields stress, it turns out that the first critical mode (the alternate bar mode) is characterized by a very small value of the critical width to depth ratio. Furthermore, the order-m mode being characterized by a critical value of the width to depth ratio equal to m times the critical value for the first mode, it follows that for large values of the mean Shields stress several unstable modes are simultaneously excited for relatively low values of the aspect ratio. This suggests that the actual bar pattern observed in nature may arise from an interesting nonlinear competition among different unstable modes.


Author(s):  
Carlos A. Hernández J. ◽  
Klaus Gocke

Between January 1987 and January 1988 the primary productivity and related parameters were studied in the Ciénaga Grande de Santa Marta. The Ciénaga is a coastal lagoon with an area of 423 km'2 and mean depth of 1.6 m, which is located at the Caribbean coast of Colombia. The salinity fluctuates seasonally within a wide range. The system is characterized by a high concentration of seston and a great primary productivity. The concentration of chlorophyll " a " ranged from 5.6to 181 ug Ii , the mean value was 59 ug I i . The concentration of proteins was within the extremes of 0.9 and 9.5 mg I"i f the mean value was 4.2 mg I ] . The gross primary productivity in the central part of the Ciénaga amounted to 1690 g C m*2 per year. Considering the temporal fluctuation in the whole system the lowest and highest values were 1.40 and 16.3 g C rrr2 per day. Highest productivity values were encountered when the salinity was low. The primary productivity is controlled by water turbidity and availability of nutrients, thus, seasonal continental waters. The photosynthetic laver ¡s restricted to less than 1.5 m due to the high particle concentration. The mean N: P relation was 4:1 which indicates that the nitrogen compounds are the limiting nutrientes. The high primary productivity sustains an important local fishery. The coastal area in the vicinity of the Ciénaga Grande is benefitted by the export of particulated and dissolved organic matter produced in excess within the coastal lagoon.


2010 ◽  
Vol 85 (2) ◽  
pp. 146-152 ◽  
Author(s):  
G.N. Madanire-Moyo ◽  
M.M. Matla ◽  
P.A.S. Olivier ◽  
W.J. Luus-Powell

AbstractAn investigation was conducted into the parasitic infection of an indigenous cichlid, Oreochromis mossambicus, collected seasonally from the Nwanedi-Luphephe dams of the Limpopo River System from July 2007 to April 2009. Of 157 host specimens examined, 115 (73.25%) were infected by at least one gill parasite. In all, 1565 monogenean specimens were collected, belonging to five different species and two genera: Cichlidogyrus (C. halli, C. sclerosus, C. tilapiae and C. dossoui) and Scutogyrus (S. longicornis). Infracommunities were poor, with only 27 (17.20%) hosts harbouring four of the five species observed. Cichlidogyrus halli was the dominant species, with a prevalence of 73.25%. Prevalence values for each of the other four species were less than 50%. The mean intensities for each of the five species were low ( < 8 parasites/host). The parasite abundance and intensity levels were not influenced by either the sex or the size of the host. The abundance of all parasite species except for S. longicornis exhibited seasonal fluctuations, reaching peaks in winter and summer. The spatial distribution of each parasite was studied on different regions of the gill, and positive associations among some species were revealed.


2021 ◽  
Author(s):  
TATYANA KEYTY DE SOUZA BORGES ◽  
AUREO SILVA DE OLIVEIRA ◽  
RICHARD G. ALLEN ◽  
AYSE KILIC ◽  
JOÃO PAULO CHAVES COUTO ◽  
...  

Abstract Understanding how solar and terrestrial radiation fluxes interact with natural surfaces and impact water consumption is of wide interest. In eastern sub-humid Bahia, Brazil, scarce surface water stored in lined ponds is used to drip irrigate Sumatra tobacco plants grown under partial shading. This work aimed at monitoring, over two irrigation seasons (2015 and 2016), the water turbidity, the radiation balance (shortwave – SW and longwave – LW components), and the skin water temperature (Tw) in the center of a large storage pond to better understand the energy balance of the storage pond and its impact on evaporation. Auxiliary data from a collocated weather station were also collected. The water turbidity was very low (around 2.6 NTU on average) due to filtration and reverse osmosis of water prior to storage. The mean daily Tw (26.1°C) was nearly always higher than the mean air temperature Ta (21.8°C) due to near-surface absorption of solar radiation. Incoming (Sg) and net SW (Snet) fluxes decreased by 70% on average with cloud cover while downward LW flux increased by 14% due to increased net atmospheric temperature with the presence of clouds. A mean daily albedo of 0.05 was measured for the type of water stored in the irrigation tanks. The net LW flux (Lnet) was consistently negative (−55.1 W m−2 average). Two approaches are proposed for estimating daily net all-wave radiation Rn. The first is Rn = −27.357 + 0.832⋅Snet (r2 = 0.998 and SEE = 9.66 W m− 2) and the second is Rn = Snet – Lnet(MLR) where Snet = 0.95∙Sg for both approaches and MRL represents a multiple linear regression model (r2 = 0.721 and SEE = 6.87 W m− 2). Both approaches use data that are easily collected from a standard automatic weather station.


Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 436
Author(s):  
Mehmet Cemal Oğuz ◽  
Andrea McRae Campbell ◽  
Samuel P. Bennett ◽  
Mark C. Belk

Distribution and abundance of common parasitic nematodes in marine fishes is not well documented in many geographic regions. Understanding the influence of large-scale environmental changes on infection rates of fish by nematodes requires quantitative assessments of parasite abundance for multiple host species. We collected samples of two species of cod and eight species of rockfish (total of 232 specimens) from waters near Kodiak Island, Alaska, USA during Spring and Summer of 2015, and dissected and recorded all internal nematode parasites. We quantified the prevalence and intensity of nematode parasites in the ten host species, and tested for differences in prevalence among host species. We found three species of nematode: Anisakis simplex, sensu lato (Van Thiel), Pseudoterranova decipiens, sensu lato (Krabbe), and Hysterothylacium sp. (Ward and Magath). Eighty-two percent of the examined fish were infected with at least one parasitic nematode. The overall prevalence of P. decipiens, A. simplex, and Hysterothylacium sp. was 56%, 62%, and 2%, respectively. Anisakis simplex and P. decipiens were abundant and present in all ten species of host fish examined, whereas Hysterothylacium sp. was rare and found in only five of the host fish species. Prevalence and mean intensity of P. decipiens and A. simplex varied across the ten host species, and the number of parasites varied substantially among individual hosts within host species. The mean intensity of P. terranova and A. simplex in our study was substantially higher than the mean intensity for these same species from multiple other locations in a recent meta-analysis. This study provides a baseline of nematode parasite abundance in long-lived fish in waters near Kodiak Island, AK, and fills an important gap in our quantitative understanding of patterns of occurrence and abundance of these common and widespread parasites of marine fish.


2014 ◽  
Vol 1010-1012 ◽  
pp. 88-95
Author(s):  
Yi Wang ◽  
Xiao Yan Ding ◽  
Hao Yang ◽  
Ji Wei Hu ◽  
Fan Jiang ◽  
...  

Both single pollution index and integrated pollution index methods were employed in the present research to assess the heavy metals pollution of soil in the threeRosa roxburghii TrattPlanting Bases (located in Qianxi County and Qixingguan region in Bijie, Longli County in Qiannan), the baseline values of heavy metals in soils in Guizhou Province, Environmental Quality Standard for Soils (GB15618-1995) and Conditions of Green Food-tech0.nical Environmental Quality for Production Area (NY/T391-2000 and GB/T18407.1-2001) were applied as references. National Food Safety Standard-Contaminants in foods was applied to evaluateRosa roxburghii Trattfruits. The results suggest that the studied soil samples conformed to Environmental Quality Second Level Standard for Soils and Green Food-technical Conditions. The overall quality of the soil conditions was uncontaminated, but point source pollution phenomenon existed. Hg, Pb and Cu pollution were the main factors contributing to the rise in comprehensive pollution index from the threeRosa roxburghii TrattPlanting bases. It was found that levels of As and Cu did not exceed the limited standard of the soil,while Hg, Cr, Cd and Pb exceeded the standard in different degrees in studiedRosa roxburghii Trattplanting bases. The rates of excessive quota of Hg, Cr, Cd and Pb in the studiedRosa roxburghii Trattfruits was 6.67%, 13.33%, 73.33% and 100%, respectively. The mean accumulation coefficient of Cd forRosa roxburghii Trattfruits was up to 1.20. The mean accumulation coefficients for concerned heavy metals were in the order of Cd > Cu > Pb > Hg > As> Cr. The relationships between concentrations of heavy metals in soil, leaf and stem samples were weak. However, significant correlations were found between concentrations of As in soil and leaf samples (r = 0.928), and concentrations of Cr between in soil samples and Cr in leaf samples (r = 0.733).


Author(s):  
Richard Nagy ◽  
Ľudmila Mečiarová ◽  
Silvia Vilčeková ◽  
Eva Krídlová Burdová ◽  
Danica Košičanová

This paper emphasizes the importance of environmental protection regarding the reduction of energy consumption while maintaining living standards. The aim of the research is to observe the effects of mechanical and natural ventilation on energy consumption and building operation as well as indoor environmental quality (IEQ). The results of indoor environmental quality testing show that the mean relative humidity (31%) is in the permissible range (30%–70%); the mean CO2 concentration (1050.5 ppm) is above the recommended value of 1000 ppm according to Pettenkofer; and the mean PM10 concentration (43.5 µg/m3) is under the limit value of 50 µg/m3. A very large positive correlation is found between relative humidity and concentration of CO2 as well as between the concentration of PM5 and the concentration of CO2. The most commonly occurring sick building syndrome (SBS) symptoms are found to be fatigue and the feeling of a heavy head.


2006 ◽  
Vol 28 (3) ◽  
pp. 121-128 ◽  
Author(s):  
Emerson Iossi ◽  
Fabiola Vitti Moro ◽  
Rubens Sader

The objective of this study was to investigate the morphology, anatomy and germination behaviour of Phoenix roebelenii seeds. Biometric data were obtained by measuring 100 seeds extracted from recently harvested fruits and air-dried for one day. Four replications of 50 seeds each were previously treated with Vitavax-Thiran and then put to germinate in Sphagnum sp. in plastic trays at room temperature. Morphological details of the seeds were documented with the help of a scanning electronic microscope and then drawings were made with the help of a clear camera coupled to a stereomicroscope. Permanent lamina containing embryo sections were prepared to study its anatomy. The mean dimensions of the seeds were: length of 10.32mm, width of 5.21mm and thickness of 3.91mm. The weight of one thousand seeds was of 151.1g and the mean number of units.kg-1 was 6,600. Germination started between 27 and 58 days after sowing. The seeds are of the albuminous type, the endosperm is hard and the embryo (which is not clearly differentiated) occupies a lateral and peripheral position. During seed germination, seedling protrusion begins with the opening of an operculum, through which the cotyledon petiole is emitted with the embryonic axis at its tip. The portion of the cotyledon petiole that remains inside the seeds acts as a haustorium for the absorption of nutrients from the endosperm. The plumule emerges through a rift in the posterior part of the cotyledon. Secondary roots are observed to grow from the anterior part of the primary root.


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