Fishpond Area Research Articles

Histopathology of liver and kidneys of wild living Mallards Anas platyrhynchos and Coots Fulica atra with considerable concentrations of lead and cadmium

Concentrations of cadmium and lead were measured in liver and kidneys of Mallard (n=60) and Coot (n=50). Free living birds were collected by hunters in years 2006–2008 in the area of fishponds near Zator in southern Poland. Age group was determined according to the appearance of the plumage (Mallards) and iris color (Coot). Concentrations of metals were measured with ET-AA spectrometer. Among all birds specimens with negligible (n=5) and high concentrations (Mallards n=18 and Coots n=17) of cadmium and lead were chosen for further analysis. Histopathological alterations were observed, ranging from circulatory disturbances, retrogressive changes, inflammations to leukocytic infiltration in liver and kidney. They dominated among birds with the highest concentrations of metals. The control group of birds was characterized by a very small number of mentioned lesions. Probably the higher cadmium and lead concentrations in tissues are co-factors in the development of lesions.

Population date of Great Cormorant at the area of the Hortobágy Fish Farm Co.

Hungary’s great cormorant stock did not use to be a considerable one before the 1980s. After that, their number has been rising significantly. The size of the stock now is rather stagnating or slightly growing. The presence of cormorants has been significant around ponds of the Hortobágy Fish Farm in the past few years. Due to considerable fish consumption of cormorants it is essential to know which and what kinds of units of the ponds (spawning, supply, and market) are preferred by the birds in order to see to adequate protection. The aim of our research was to discover any differences in the number of cormorants present at particular units of the fishpond system and certain ponds of equal kinds within them.
 Our observations were in line with the methods used in ornithological researches. The experiment took place between April and October 2012 on a monthly basis. According to the results we found relevant differences in the number of cormorants based on the seasons and months as well. This fact was supported by statistical data. During the autumn and winter birds prefer supply and market purpose ponds while their presence here is vanishing during the summer. Relevant presence of cormorants around the area of the Old Fishponds (70 to 200 specimens) might be due to lack of disturbance and large sizes of the ponds.
 Our research has great scientific relevance since it is vital to be aware of the preferred periods and areas in order to maintain effective protection; this way alerting activities can be applied in a more harmonized way. By keeping our research up as a monitoring activity, we will be able to receive more precise data later on.

Feeding habits of invasive American mink (Neovison vison) in northern Germany—potential implications for fishery and waterfowl

In order to collect ecological data of invasive American mink (Neovison vison) at a fishpond area in northeastern Germany, we conducted a telemetry study in which 14 mink were radio-tracked. During this project, 2,502 scats from radio-tracked individuals were collected in the period from October 2003 to October 2005. Investigated mink principally prey on fish, small mammals and birds (eggs inclusive), whereas amphibians, reptiles and invertebrates were caught infrequently. Analysing mink scats of different seasons, we found significant seasonal variations of diet composition. In spring, fish, mammals and birds were hunted in similar amounts. During summer, birds made up the main part of the diet followed by mammals. In autumn, the proportion of birds in the mink diet decreased, whereas fish gained in importance. This trend continued during the winter period, when mink preyed almost exclusively on fish. Amphibians, crustaceans, insects, molluscs and reptiles were found only occasionally in scat samples. Among birds, the mink preyed mainly on the Eurasian Coot (Fulica atra) followed by the Mallard (Anas platyrhynchos). Mammalian prey was clearly dominated by the water vole (Arvicola terrestris) and among fish, mink hunted especially perch (Perca fluviatilis), roach (Rutilus rutilus) and carp (Cyprinus carpio). Results clearly demonstrate that mink is an opportunistic predator, which hunts its prey according to availability and vulnerability, respectively. Despite the high portions of fish in their autumn and winter diet, the economic damage caused by mink seems to be negligible. However, high predation rates on birds during the breeding season indicate a potential negative impact of mink on waterfowl.

Assessment of Environmental Quality of Coastal Fishpond Areas Using Macrobenthic Structure: Multivariate and Graphical Approaches

Environmental degradation that results in decreased quantity of farmed fish production is an issue that often arises in rapid aquaculture industry. This study aims to develop the method of environmental quality assessment of aquaculture using macrobenthic structure to ensure the sustainability of its activity. The research was conducted at three fish farming sites along coastal of Sayung, Demak Regency, Central Java, i.e. milkfish ponds, shrimp ponds, and mixture pond. Determination of the environmental quality of the farms was done by analyzing data and environmental parameters and macrobenthic abundance and biomass using multivariate and the graphical methods. The results of Principle Component Analysis (PCA) projected from an aquatic environment parameters showed no signs of grouping based on three types of ponds, but there are signs of grouping by time sampling, indicating fluctuations in physico-chemical conditions of waters over time. Based on the macrobenthic abundance, study sites were dominated by gastropods (97%), the rest of bivalves (2%) and polychaetes (1%). Results from ordination analysis, ABC curves and k-dominance showed no signs of clustering by types of pond, but between sampling times. This implies that multivariate and graphical methods can sensitively detect any environmental change, particularly changes in macrobenthic community, water quality and sediment over time.

Dynamics in space use of American mink (Neovison vison) in a fishpond area in Northern Germany

Telemetry of American mink Neovison vison revealed seasonal and sexual variations in home-range size, intersexual- and partially intrasexual range overlaps and spatial dynamic of territorial system. From 2003 to 2006, 14 mink (nine males and five females) were radio-tracked in a fishpond area in northern Germany. We observed comparatively large home ranges. Both sexes reduced their large summer home ranges to smaller ones in the winter period. In both seasons, male mink used significantly larger areas than female mink. During the mating season, males considerably enlarged their home ranges and roamed nearly through the entire study area. These variations and diversity of range size were discussed in connection with thermoregulatory behaviour, prey availability and distribution, population density and stability of the social system. Analysing intraspecific static interactions, we observed high intersexual overlapping rates in both the summer and winter periods. But there were no or rather very low levels of intrasexual overlapping. However, in the summer period, large home ranges of neighbouring males also overlapped to some extent, but temporal avoidance of adjacent territory holders was observed. Consequently, our results reveal intrasexual territoriality, with males having larger territories, overlapping those of females. The shifting of stable temporary home ranges observed within one season or between the same seasons of consecutive years demonstrates the highly dynamic nature of spatial behaviour among American mink. All these recorded characteristic features of spatial behaviour should be considered when planning mink control projects and measures for the management of this invasive carnivore.

BOEZEM WONOREJO RUNGKUT DI GUNUNG ANYAR SEBAGAI ALTERNATIF PENGENDALI BANJIR DI WILAYAH SURABAYA SELATAN

Surabaya as the Capital of East Java Province is a settlement area and also as the centers of Industry, Trade, Service, Education. Due to the development of all activities lines grow rapidly, including the supplying of housing, industrial plants, thus automatically they change the land functions (land use), and the river functions formerly as the irrigation but now changed to be the drainage, causing the increasingly large of flow coefficient, also increasingly large the surface overflow discharge. With the changes, they change irrigation canal functions become the drainage, that bring the river constriction impact, that the river no longer able to hold and channeling flood discharge both come from the upper course, and due to the local rainfall occurred continually in the dry season, water will overflow to flood the areas with the low elevation under sea level, causing the prolonged water backup, as a result, disturb the economy wheel circulation, causing the big losses. To overcome backup water many things we can perform, such as waterworks widening, sediment dredging, and the making of dike heightening, waterway diversion. By the consideration that costing is expensive and the difficult of area (land) deliverance at the settlement area in order to overcome the water backup/flood, then the solution as alternative can be taken is revitalization of Wonorejo Boezem in Gunung Anyar of Rungkut area, where its land is not productive (non productive fishpond area) with the shallow condition. Instead of revitalization, it is also developed the new construction or enlargement of reservoir capacity in the Boezem. From the results of this research consistent with the work items result in as follows: Sum the design flow discharge as much as 51.4863 m3/s(C.I.A)+0,446 (gross water discharge people) + 0.3327 m3s (gross water discharge Industry) = 52.165 m3/s with the repeated period scale of 10 years, while the reservoir discharge capacity of Wonorejo Boezem as much as less than 570,874 m3 need th design flow discharge as much as 586.000 m³s and the drainage flowing water to the Boezem, the drainage dike height is 1.50 m with water level of 1.25 meters and wide 28 meters, then in order to suppress the budget costing for flood control in Southern Surabaya Area, as the alternative is by function maximally on the Wonorejo Boezem reservoir, still sufficiently can overcome flood.

Parasites in a man-made landscape: contrasting patterns of trematode flow in a fishpond area in Central Europe

We have explored a large body of novel data focusing on small-scale temporal and spatial patterns in the composition and structure of larval trematode communities in Lymnaea stagnalis (L.) from a typical Central European agricultural landscape. The 5 eutrophic fishponds studied provide excellent environments for the development of species-rich and abundant trematode communities. Nine prevalent species were consistently present in component communities, but had differential contribution to the parasite flow in the 5 ponds resulting in significant contrasting patterns of community similarity and the prevalence of the 3 major transmission guilds driving this similarity. Component communities split into 2 groups: (i) those from the large pond dominated by anatid and larid generalists with active miracidial transmission; and (ii) those from the smaller ponds dominated by 2 plagiorchioideans infecting snails via egg ingestion. We put forward 3 hypotheses for the remarkable differences in larval trematode flow in the similar and closely located eutrophic ponds: (i) species-specific differences in parasite colonization potential displayed by an 'active-passive' dichotomy in miracidial transmission strategies of the species; (ii) top-down effects of pond context on transmission pathways of the trematodes; and (iii) competition as an important mechanism in eutrophic environments with a bottom-up effect on component community structure.

Otters vs. fishermen: Stakeholders’ perceptions of otter predation and damage compensation in the Czech Republic

Habitat destruction and extensive hunting drove the population of Eurasian otter ( Lutra lutra L.) in Central Europe nearly to extinction. Due to conservation efforts, otters are now returning to their original habitats, including fishpond areas in the Czech Republic. As their populations grow, conflicts with fishermen arise due to significant losses of commercial fish stocks caused by otter predation. Since 2000, Czech fisheries may claim compensation for otter damages under legislative Act No. 115/2000. However, negative attitudes towards otters persist and their illegal killing remains common. In order to provide decision-support material for conflict reconciliation, we conducted a questionnaire survey among fishermen ( n = 125) and conservationists ( n = 36) to investigate stakeholders’ perceptions of otter predation and the damage compensation scheme in the Czech Republic. Results suggest that although otter damages on fish stocks were smaller than those caused by other piscivorous predators, fishermen perceived them as a significant hardship and demanded active control of otter populations. However, only one quarter of fish farmers actively protected their ponds from otter predation and not all conservationists were able to provide advice on preventive measures. Most respondents were aware of the current compensation scheme but its actual utilisation, especially by small private fish farmers, was low due to a perceived bureaucratic burden. All stakeholders considered current compensations to be insufficient and expressed a need for additional measures. We identified deficiencies in communication between both groups of stakeholders, and a lack of knowledge and use of available damage mitigation options. Our findings show prevailing gaps in the conservation plan for L. lutra and suggest areas into which the effort of conservation planning, public relations, and environmental awareness campaigns should be targeted. Understanding stakeholders’ attitudes towards mitigation strategies is crucial for their successful application and for future improvement of reconciliation policies focused on conflicts between human activities and protected species.

Leptospirosis distribution related to freshwater habitats in the Vojvodina region (Republic of Serbia)

The retrospective study (2002-2007) for human leptospirosis in Vojvodina was undertaken in order to describe the distribution of the disease in relation with some environmental factors. Regarding the presented results, the major detected number of leptospirosis cases concurs with stagnant waters, wetlands, fish pond areas and protected regions, which comprised the basis for mapping of the region in three risk zones: very high risk (incidence rate higher than 5.0), high risk (2.5-5.0) and medium risk of leptospirosis infection (1.0-2.5). During the investigated period, 97 cases were registered with an average of 13.85 cases per year: 2002, 32 cases; 2003, 7; 2004, 22; 2005, 16; 2006, 4 and 2007, 16. Out of these 97 cases only 5 were women. Serovars from 11 presumptive serogroups caused infection, with a predominance of Icterohaemorrhagiae and Bratislava, accounting for 72.72% of cases together. Icterohaemorrhagiae was the commonest infecting serogroup mostly connected with fish ponds. Case fatality ratio was 9.4%.

Gender differences in activity patterns of American mink Neovison vison in Germany

Circannual and circadian activity patterns of American mink Neovison vison were studied in a fishpond area in northern Germany. Fourteen mink were radiotracked, nine of them (five males, four females) for at least 6 months, some of them even up to 21 months. Both sexes have reduced activity rates in winter months and showed a considerable increase of activity during mating season (March). In summer months—during the pup raising period—female activity continued to be high. Male mink, on the other hand, were less active with the exception of August and September. During this time, dispersal of juveniles takes place with resident males increasingly having to defend their territories. Circadian activity rhythms differed markedly between sexes. All investigated females exhibited a perennial diurnal pattern. Female activity during twilight and night was significantly lower than during daylight. Three investigated male mink showed a typical nocturnal course throughout the year. Daylight activity of these animals was very low, increased during dusk and dawn activity rates and stayed at a higher level during the night. Two males behaved arrhythmic; they did not prefer any time of the day for activity. The observed temporal strategies were discussed in context of intra-sexual territoriality, sexual dimorphism in body size and different environmental factors.

An evaluation of field and noninvasive genetic methods for estimating Eurasian otter population size

Successful conservation and management of rare and elusive species requires reliable estimates of population size, but acquisition of such data is often challenging. We compare the two most frequently used methods of assessing abundance of Eurasian otter (Lutra lutra) populations, noninvasive genetic sampling (NGS) based on genotyping of faeces and field surveys using snow tracking. In a 100-km2 oligotrophic otter habitat with linear water bodies, both methods yielded very similar estimates (10–12 individuals). However, in a 100-km2 fishpond area, consisting of a complex network of rivers, fishponds, channels and marshes, genotyping of faeces revealed the presence of a higher number of individuals (46–50 genotypes) than the snow survey (38 individuals). NGS data analysed by capture-mark-recapture (CMR)-based software CAPWIRE provided even higher estimates, being twice the number assessed through snow tracking (76–81 individuals, CI95% = 49–96 and 55–89). Our results suggest that the performance of both NGS and snow tracking is comparable in simple linear habitats, but in complex habitats with very high otter density a combination of genetic and field methods, or CMR analysis using genetic data, is recommended. We emphasise that to obtain reliable estimates using NGS it is necessary to follow strict protocols for detection and elimination of genotyping errors. Based on a literature review and our experience, we suggest improvements that may increase the success rate and efficiency of NGS for otters.

Status, distribution and long-term changes in the waterbird community wintering in Doñana, south–west Spain

The Guadalquivir Marshes or Doñana wetland complex is the most important wintering site for migratory waterbirds in the Mediterranean region. However, there is a lack of previous information on the status of different species in this area. Using monthly aerial counts conducted from 1978 to 2005, we analysed the size of wintering populations of 21 waterbird species, their distribution within the Guadalquivir Marshes, and their long-term population trends. We used Underhill indices to replace missing values and to correct for flocks of unidentified ducks. Based on long-term means, we identified 16 species whose populations at Doñana exceed 1% of the biogeographical flyway population. For at least 1 month of the year, mean counts were around 10% of the flyway population for six species. The natural, temporary marshes of Doñana National Park were particularly important for Anatidae, ricefields for gulls, white storks and grey herons, fish ponds for flamingos, cormorants and avocets, and salt pans for shelduck. Four Anatidae species have undergone long-term declines and eight non-Anatidae have undergone long-term increases. Population trends were related with trophic guild, migratory status and habitat use. Winter visitors and herbivorous species showed more negative trends than resident, omnivorous–carnivorous species. Those species concentrated in strictly-protected natural marshes have tended to decline. The surface area of ricefields and fish ponds has increased over the study period, and bird species concentrated in these artificial wetlands have tended to increase. This raises questions about the value of waterbirds as flagship or umbrella species for wetland conservation.

Tidal inundation mapping under enhanced land subsidence in Semarang, Central Java Indonesia

Tidal inundation by high tide under enhanced land subsidence is a damaging phenomenon and a major threat to the Semarang urban area in Indonesia. It impacts on economic activities, as well as the cost of an emergency program and causes interruption of pubic services, danger of infectious diseases and injury to human lives. This study examines a spatial analysis tool on the GIS-raster system for the tidal inundation mapping based on the subsidence-benchmark data and modified detail digital elevation model. Neighborhood operation and iteration model as a spatial analysis tool have been applied in order to calculate the encroachment of the tidal inundation on the coastal area. The resulting map shows that the tidal flood spreads to the lowland area and causes the inundation of coastal settlement, infrastructure, as well as productive agricultural land, i.e., the fish-pond area. The monitoring of the vulnerable area due to the tidal inundation under the scenario of extended land subsidence plays an important role in long-term coastal zone management in Semarang.

ASSESSMENT OF COASTAL LAND USE CHANGES IN BANTEN BAY, INDONESIA USING DIFFERENT CHANGE DETECTION METHODS

Many types of the coastal land use in Banten Bay have been assessed in order to know the change as evidently detected by Landsat imagery in 1994 and 2001. Image processing such as, supervised classification and various change detection techniques are performed to the satellite images. Red Green method showed the best result for detecting the coastal land use change. This method is suitable for detecting the increasing areas of the paddy fields and settlement. Image Differencing method is capable to detect the increasing areas in agriculture, decreasing in fishponds and natural areas. Image Ratioing method can be considered suitable for detecting the increasing area of fishponds, decreasing of paddy fields and agriculture areas. Each coastal land use type has increased, except for the natural area/brushwood. Most of agriculture and paddy fields areas have been converted to fish ponds. Key words: coastal land use/land cover, change detection method, remote sensing

Food Provisioning in Red-Necked Grebes (Podiceps Grisegena) at Common Carp (Cyprinus Carpio) Ponds

Parental feeding patterns were studied in red-necked grebe (Podiceps grisegena) broods throughout the entire period of parental care in a common carp (Cyprinus carpio) fish-pond area in SE Poland in 1993–2002. Fish formed a substantial part of prey provided to the flightless young from their second week of life. Although the numbers of large invertebrates and tadpoles, the alternative prey to fish, did not decrease during the chick rearing period, grebe parents gradually shifted from delivering predominately invertebrates to delivering fish, and the average size of fish fed to chicks increased with brood age. Broods with relatively high fledging success (at least two chicks fledged) had a larger proportion of fish in their diet than broods seriously reduced because of undernourishment. The dive duration of foraging grebe parents did not differ between carp, wild fish and non-fish prey, but carp prey required significantly more time for handling. The percentage of prey rejected by chicks increased over the prefledging period from 2 to 24%. Of the prey rejected, 82% were fish apparently too large for the young to swallow. Fish prevalence in the diet of red-necked grebe chicks at carp ponds contradicts the results of other studies on the feeding habits of the nominative subspecies during breeding season. However, the red-necked grebe is a gape-limited predator and the piscivory of the chicks is limited to small-bodied fish.

Insecticide impregnation can restore the efficiency of torn bed nets and reduce man-vector contact in malaria endemic areas

Three trials with torn bed nets impregnated with permethrin and deltamethrin were made under field conditions at the Soumousso Field Station and the Vallée du Kou rice-field area, both in Burkina Faso, and the Djoumouna fish pond area in the Congo Republic. Even a considerably torn correctly impregnated bed net could be an useful method for limiting human-anopheline contacts. But bed nets in poor condition, i.e. too little impregnated and too much torn, cannot protect the users against anopheline bites. Protection increases with insecticide concentration, but at a high dosage insecticide could have more a repellent than a killing effect. Therefore a balance has to be found for the optimum rate of insecticide treatment of bed nets to obtain a real reduction in malaria transmission and morbidity, in every epidemiological situation.

Sucrose-inversion temperature measurements in fishpond littoral vegetation

The sucrose-inversion method of temperature measurement was employed for characterizing the spring, summer and winter microclimatic conditions in a Central European fishpond reed belt colonized by terrestrial, limosal and littoral stands of Phragmites and by Typha, in a patch (“lagoon”) of open water within the reed belt, and in the central open part of the fishpond. A sharp temperature differentiation develops in the spring, determined mainly by the insulating effect of dead plant material present. In summer, the canopy density and degree of mixing of the littoral water with that of the central open fishpond area are of primary importance. The winter temperatures of the water and soil are primarily determined by the penetration of direct radiation to their surface: the amount of dead plant material is therefore of importance as well, but the microclimatic differentiation is poorer than in spring. The inaccuracies introduced by conversion of exponentially temperature-dependent sucrose-inversion to arithmetical mean temperature are discussed.