A comparison of fish assemblages from seagrass and unvegetated areas of a southern Australian estuary

1994 ◽  
Vol 45 (6) ◽  
pp. 1033 ◽  
Author(s):  
RM Connolly

Assemblages of small fish from eelgrass (mainly Zostera muelleri) and unvegetated patches in a shallow, marine-dominated estuary were compared over one year as a preliminary step towards finding the consequences of eelgrass loss to small fish. There were more species and more individuals at eelgrass sites than at unvegetated sites at every sampling period. Multivariate analysis (MDS ordination) of assemblages showed distinct grouping of eelgrass and unvegetated sites. The statistical significance of groupings was tested by using an analysis of similarities (ANOSIM) randomization routine. The cryptic syngnathid Stigmatopora nigra and juvenile whiting, Sillaginodes punctata, the species of greatest economic importance in the estuary, were predominantly over eelgrass, whereas the flounder Rhombosolea tapirina was usually caught at unvegetated sites. Atherinosoma microstoma, the most abundant species, was more common over eelgrass at two dates but had similar abundances over both habitats at other dates. The limitations of survey work caused by possible associations between the presence of vegetation and environmental factors have been partially offset by interspersion of sites and by measurement of water temperature and salinity. Secondarily to habitat differences, fish assemblages were weakly grouped according to distance of sites from open water.

1993 ◽  
Vol 27 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Almério de Castro Gomes

Populations of Anopheles (Kerteszia) were sampled fortnightly over a one-year period (August 1991 to July 1992) at Ribeira Valley, S. Paulo State, Brazil. Indoor and outdoor collections were made on human bait at evening crepuscular period. The Polovodova technique for age grading was applied to 3,501 females of Anopheles cruzii and to 416 females of An. bellator. That sample represented 34.4% of the total number of mosquitoes collected. The most abundant species found was An. cruzii. However, An. bellator showed an endophagy that was almost three times greater than that of An. cruzii. The overall parous rate was 25.4% and uniparity was practically dominant one. A proportion of 26.9% of An. cruzii and 12.0% of An. bellator were found to be uniparous. Only three outdoor females of the former species (0.1%) showed biparity. Parity of An. cruzii was higher in females caught outdoors than in those caught indoors. Nevertheless, 497 nulliparous females examined (417 cruzii and 80 bellator) had ovaries that had advanced to Christophers and Mer stages III to V. These results imply that these females had already practised hematophagy. Relating these results to those from the parous females, a high statistical significance was found, leading to the conclusion that gonothophic discordance is a common pattern among these anophelines. Further, these results obtained with human bait catches strongly suggest that nearly 38.0% of these host-seeking females had already taken at least one previous blood-meal. So it is possible that enough time could thus be available for the plasmodian development in the vectors.


Author(s):  
Jane E. Jelbart ◽  
Pauline M. Ross ◽  
Rod M. Connolly

Beds of the seagrass Zostera capricorni are an integral part of the estuarine landscape along the east coast of Australia, forming an important habitat for juvenile fish. Seagrass beds can vary in their size, shape and patchiness of seagrass cover as well as their distance from the estuary mouth. We tested for a correlation between these features and small fish assemblages in seagrass. Fifteen beds were selected from three size-categories (small, 980 to 2300 m2; medium, 3375 to 4090 m2; and large, 5335 to 6630 m2). We found that the size of beds, the patchiness of seagrass cover and location within the estuary (distance from estuary mouth) were all related to differences in fish assemblages. There were greater densities of fish species in small (10.3 ±0.79 species .net-1) compared to medium (7.6 ±0.6) and large (8.2 ±0.5) beds. This occurred regardless of bed placement within the estuary, its patchiness or time of sampling (day and night). The fish assemblages within seagrass beds also changed as bed distance to estuary mouth increased. Six species had greater densities in beds closer to the estuary mouth, while only two species were in greater densities far from the mouth. Fish assemblages were different between beds with patchy and continuous cover, although total densities of all fish species combined were similar. There were greater densities of four species in continuous beds compared to two species that were greater in patchy beds. Overall, an important finding was that even small patchy seagrass beds contain greater densities of small fish species than larger beds with continuous seagrass cover.


1988 ◽  
Vol 39 (6) ◽  
pp. 709 ◽  
Author(s):  
JJ Burchmore ◽  
DA Pollard ◽  
MJ Middleton ◽  
JD Bell ◽  
BC Pease

Four species of whiting (Family Sillaginidae) were collected from Botany Bay, New South Wales, between 1977 and 1979: Sillago ciliata (sand whiting), S. maculata maculata (trumpeter whiting), S. robusta (stout whiting) and S. bassensis flindersi (eastern school whiting). Sillago ciliata was the most abundant species over-all. Sillago ciliata was caught in greatest numbers in Zostera seagrass and shallow sandy habitats, whereas S. m. maculata, S. robusta and S. b. flindersi were most abundant over deeper muddy and sandy habitats. Sillago ciliata and S. b. flindersi were present mainly as juveniles. Gonosomatic indices and gonadal maturity stages of S. ciliata and S. m. maculata peaked around February. These species probably spawn within the Bay. Length to caudal fork at first maturity was 24 cm for male and female S. ciliata, 19 cm for male and female S. m. maculata, 17 cm for male and 18 cm for female S. robusta, and 14 cm for male and female S. b. flindersi. Although all species fed mainly on polychaetes and crustaceans, there was little overlap in specific dietary items between species. Variations observed in diet were due to fish size and temporal and spatial habitat differences within and among species.


2013 ◽  
Vol 64 (10) ◽  
pp. 932 ◽  
Author(s):  
L. B. Bucater ◽  
J. P. Livore ◽  
C. J. Noell ◽  
Q. Ye

Estuaries are transition zones that link freshwater and marine ecosystems and are often used as nursery areas by fish. The Murray–Darling Basin, which is heavily affected by flow regulation and water extraction, is the largest river system in Australia and terminates at the Murray Mouth estuary. Protracted drought conditions resulted in extremely low flows to the Murray Mouth that affected water condition, fish abundance, community structure and fish use of the estuary (e.g. nursery areas). The aims of the present study were to examine temporal changes in larval fish assemblages in this estuary. The assemblages were dominated by two gobiid species, Arenigobius bifrenatus and Tasmanogobius lasti. There was a noticeable absence or low abundance of freshwater, diadramous and large-bodied marine species that use this estuary for reproductive functions. Monthly differences in larval fish assemblages, between August–September and October–November, were attributed to increases in the abundances of A. bifrenatus in October and November and oscillation in T. lasti during the entire sampling period. The outcomes of the present study suggested that larval fish assemblages in drought conditions are limited to small-bodied species tolerant of high salinities and that freshwater flows are needed for the estuary to function as a nursery for other species.


2014 ◽  
pp. 1-4
Author(s):  
T. LOPEZ-TEROS ◽  
L.M. GUTIERREZ-ROBLEDO ◽  
M.U. PEREZ-ZEPEDA

Physical performance tests are associated with different adverse outcomes in older people. Theobjective of this study was to test the association between handgrip strength and gait speed with incidentdisability in community-dwelling, well-functioning, Mexican older adults (age ≥70 years). Incident disability wasdefined as the onset of any difficulty in basic or instrumental activities of daily living. Of a total of 133participants, 52.6% (n=70) experienced incident disability during one year of follow-up. Significant associationsof handgrip strength (odds ratio [OR] 0.96, 95% confidence interval [95%CI] 0.93-0.99) and gait speed (OR0.27, 95%CI 0.07-0.99) with incident disability were reported. The inclusion of covariates in the models reducedthe statistical significance of the associations without substantially modifying the magnitude of them. Handgripstrength and gait speed are independently associated with incident disability in Mexican older adults.


2012 ◽  
Vol 42 (4) ◽  
pp. 561-566 ◽  
Author(s):  
Janette Noveras ◽  
Kedma C. Yamamoto ◽  
Carlos E.C. Freitas

We evaluated diversity and distribution of fish species in two habitats: flooded forest and open water of lakes of Rio Negro. Each of four lakes within the Anavilhanas Archipelago was sampled three times from 2009-2010. Species diversity generally was higher in flooded forests and at night, according to correspondence analysis. Predators were most active at night, but showed no preference between the flooded forest and open water habitats. Omnivores, filter feeders, and detritivores were most active during the day.


2016 ◽  
Vol 32 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Denis Kucevic ◽  
Snezana Trivunovic ◽  
Vladan Bogdanovic ◽  
Ksenija Cobanovic ◽  
Dobrila Jankovic ◽  
...  

Possible differences between composition of raw milk due to dairy farming system (organic vs conventional) as well as seasonal variations were investigated. The samples were analysed during one year. A total of 6.782 samples of raw milk were collected (4.496 from organic farming). Dairy farms were located in the northern part of Republic of Serbia (Province of Vojvodina). The principle of analysis of raw milk samples was in accordance with the methodology by midinfrared spectrometry and flow cytometry. The fixed effect of system of farming and season (winter, spring, summer and fall) have shown a high statistical significance (P < 0.01) on all examined milk parameters except fat, total solids and somatic cell count, where the impact was slightly lower (P < 0.05). Significant difference wasn't found in number of bacterial colonies (P > 0.05). Composition of milk is also affected by a number of other factors, therefore it is recommended to involve factors such as nutrition of dairy cows, breed and farm management.


2020 ◽  
Vol 8 (2) ◽  
pp. 73-77

Neonatal sepsis is one of the commonest causes of morbidity and mortality in neonates in India compared to the developed countries. Aim: To evaluate the Procalcitonin level this is an early marker in the diagnosis of neonatal sepsis and to assess the suitability of this test in the diagnosis of early-onset sepsis. Method: The prospective study was conducted in the Neonatal Division of Department of Pediatrics, Prathima Institute of Medical Sciences over a period of one year. The blood samples from 100 babies meeting the inclusion and exclusion criteria constituted the material for study. Result: Among the n=100 cases n=39 were procalcitonin positive, compared with gestational age 10 (43.5%) cases were positive with a gestation of <37 weeks and 24 (31.2%) cases positive of cases >37 weeks and there was no statistical significance concerning gestational age the association of material characteristics with procalcitonin positive and CRP positive levels. Blood culture was positive in n=9 (9%) of babies with (90% CI, 5.3-14.9) and negative in n=91 (91%) of babies with (90% CI, 85.2-94.7). Conclusion: A positive blood culture is the only definitive and gold standard for confirming a case of sepsis. Since the culture and sensitivity test requires a minimum period of 48 hours which is a precious time in deciding on the treatment of sepsis in the newborn. Rapid diagnosis by using Procalcitonin and CRP gives a reasonable degree of accuracy in diagnosing neonatal sepsis and will also guide antibiotic therapy. Procalcitonin in comparison with CRP has better sensitivity and hence can detect most cases of neonatal sepsis and better negative predictive value.


2001 ◽  
Vol 133 (6) ◽  
pp. 843-855 ◽  
Author(s):  
Dennis J. Fielding ◽  
M.A. Brusven ◽  
Bahman Shafii ◽  
William J. Price

AbstractThe objectives of this study were to determine whether the spatial distribution of Melanoplus sanguinipes F., the most abundant species of grasshopper on rangeland in southern Idaho, varied annually in response to changing patterns of grazing and to investigate how vegetation affects the spatial distribution of low-density populations of M. sanguinipes at scales relevant to most rangeland-management activities. A lattice of 72 sites was established across nine pastures, covering approximately 5000 ha. At each site, densities of M. sanguinipes, percent canopy coverage by plant species, and percent forage utilization by livestock were estimated twice per year, in June when M. sanguinipes was in the nymphal stage and in August during the adult stage, for 4 years, 1991–1994. Spatial analyses of variance were used to evaluate the influence of grazing and vegetation type on densities of M. sanguinipes. In August of each year, densities of M. sanguinipes were lower on heavily grazed sites than on lightly grazed sites, except in 1993, when the opposite trend was observed. Above-normal precipitation in 1993 resulted in abundant growth of annual forbs and regrowth of grazed plants. The distribution of nymphs in June of 1993 and 1994 reflected the grazing patterns of the previous summer. Densities of M. sanguinipes were lower on crested wheatgrass habitats than on annual grasslands for every sampling period from June 1991 to June 1993, after which no differences were observed. We interpret the results to suggest that grazing effects on low-density populations of M. sanguinipes were contingent on weather conditions; under dry conditions, grazed habitats were less favorable to M. sanguinipes but, during relatively cool wet summers, grazing created conditions that were more favorable to M. sanguinipes.


Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
I.A. Russell

Fish assemblages were sampled at nine sites in the lower Vaal River in the Vaalbos National Park and adjacent properties. A total of 1543 fish from 10 species was recorded. Ordination revealed spatial variation in assemblage structure, with the distinction primarily between communities in rapids and deep pools. Flow velocity, depth and percentage cover were important determinants offish assemblage structure. The length frequency distribution of abundant species indicated successful recruitment. Several differences in the species compliment compared to earlier studies were evident, including high abundance of Barbus paludinosus and Austro^lanis sclateri, and the absence of Barbus anoplus. The length-mass relationships of large cyprmids indicated long-term declines in the physical condition of fish.


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