Km Upstream (km + upstream)

Distribution by Scientific Domains

Selected Abstracts

Lateral movement of common carp (Cyprinus carpio L.) in a large lowland river and floodplain

M. J. Jones
Abstract,,, Common carp (Cyprinus carpio L.) are a major freshwater invader and knowledge of their movements is important for planning control efforts. To investigate the movement patterns of common carp, radio-tags were implanted into 46 adult fish; 37 near a large floodplain wetland, the Barmah-Millewa forest, and 9 in the Murray River approximately 175 km upstream. Tagged fish were located every second week between August 1999 and March 2001. Common carp occupied total linear ranges (TLR) between 0.4 and 238 km (mean 30 ± 61 km), with 25 fish (62.5%) occupying a TLR < 10 km. Two fish made large distance movements approximately 650 km downstream. Fish sex, the number of locations, time at large, or tagging location explained little variability (P > 0.05) in TLR. Monthly distance from release varied from 0.04 to 238 km (mean 15 ± 44 km), and was not significantly related to river discharge and water temperature, but 29 of 31 (93.5%) fish tagged at Barmah moved from the Murray River into adjacent floodplain habitats upon flooding. Five fish (12.5%) moved large distances (>127 km) upstream of the Barmah-Millewa forest. Fourteen fish (35%) showed site fidelity to within 20 m and usually occupied one or two home sites. Twenty-six fish (65%) showed site fidelity to within 100 m occupying up to five sites during the study period. Movement patterns of common carp were complex, and individuals exhibited different strategies, which is typical of invasive species. Efforts to control and potentially reduce common carp populations in regulated river-floodplain environments should target key floodplain access points and over-wintering habitats to reduce adult biomass, spawning and recruitment levels. [source]

Polycyclic aromatic hydrocarbons, aliphatic hydrocarbons, trace elements, and monooxygenase activity in birds nesting on the North Platte River, Casper, Wyoming, USA

Thomas W. Custer
Abstract Tree swallow (Tachycineta bicolor) and house wren (Troglodytes aedon) eggs and chicks were collected near a refinery site on the North Platte River, Casper, Wyoming, USA and at a reference site 10 km upstream. Total polycyclic aromatic hydrocarbon (PAH) concentrations in swallow and wren chicks were higher at the refinery site than at the reference site. Polycyclic aromatic hydrocarbon concentrations in sediment and chick dietary samples were consistent with these findings. The general lack of methylated PAHs in sediment, diet, and bird carcasses suggested that the PAHs were derived from combustion and not from petroleum. The predominance of odd-numbered aliphatic hydrocarbons and the low ratios (,0.25) of pristane:n -C17 and phytane:n -C18 in chick and diet samples also suggested that swallow and wren chicks were not being chronically exposed to petroleum. Mean ethoxyresorufin- O -dealkylase and benzyloxyresorufin- O -dealkylase activities in tree swallow livers averaged nine times higher at the refinery site than at the reference site and were probably induced by exposure to PAHs. Trace element concentrations in eggs and livers of swallows and wrens were similar or greater at the reference site than at the refinery site. Selenium, strontium, and boron concentrations were elevated in eggs and livers of swallows and wrens at both the refinery and reference sites. [source]

The geochemical characteristics of the Paraná River suspended sediment load: an initial assessment

Pedro J. Depetris
Abstract Most water in the Paraná River drainage basin is supplied by the tropical Upper Paraná (over 60% of the total annual water discharge, 550 km3). The total suspended solids (TSS) load (c. 80 × 106 t year,1), however, is essentially furnished (50,70%) by the mountainous, arid and mostly sediment-mantled upper Bermejo River drainage basin. This characteristic suggests that the Paraná River solid load (TSS, 600 km upstream from the mouth) is largely recycled sedimentary material, whose discharge-weighted mean chemical index of alteration is c. 71. The extended UCC-normalized multi-elemental diagrams are similar to those of other world rivers. Nevertheless, the detailed inspection of UCC-normalized rare earth element (REE) ,spidergrams' reveals a lithological source for the Paraná River TSS that might be compatible with either tholeiitic flood basalts (widespread in the upper drainage) or with young Andean intermediate volcanic rocks. In view of the Bermejo River's dominant role as a sediment contributor, we feel that the signature preserved in the Paraná's TSS is the latter. Conversely, the Uruguay River TSS REE signature is certainly determined by the extensive weathering products of Jurassic,Cretaceous tholeiitic basalts. Copyright © 2003 John Wiley & Sons, Ltd. [source]

The influence of hydroelectrical development on the flow regime of the karstic river Cetina

Ognjen Bonacci
Abstract The Cetina River is a typical karst watercourse in the deep and well-developed Dinaric karst. The total length of the Cetina River open streamflow from its spring to the mouth is about 105 km. Estimated mean annual rainfall is 1380 mm. The Cetina catchment is built of Triassic, Jurassic, and Cretaceous carbonate strata. The western part of the catchment by the Cetina River is referred to as the ,direct' or topographic catchment. It was defined based on surface morphologic forms, by connection between mountain chain peaks. This part of the catchment is almost entirely situated in the Republic of Croatia. The eastern part of the catchment is referred to as the ,indirect' catchment, and is mainly situated in Bosnia-Herzegovina. Water from the ,indirect' catchment emerges from the western ,direct' catchment in numerous permanent and temporary karst springs. Since 1960, numerous hydrotechnical works have been carried out on the Cetina River and within its catchment. Five hydroelectric power plants (HEPPs), five reservoirs, and three long tunnels and pipelines have been built. Their operation has significantly altered the natural hydrological regime. The Cetina River is divided into two hydrological reaches. In the 65 km upstream, the hydrological regime was redistributed within the year: low flows had increased and high flows had decreased, although the mean annual discharge remained the same. Part of the Cetina watercourse downstream from the Pran,evi,i Reservoir lost the majority of its flow. The mean annual discharges dropped from 100 m3 s,1 to less than 10 m3 s,1 because of the Zaku,ac HEPP development. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Patternizing of impoundment impact (1985,2002) on fish assemblages in a lowland river using the Kohonen algorithm

T. Penczak
Summary Impoundment impact on fish assemblage structure was investigated in the dammed middle course of the Warta River. A backwater site (AB) was located 2 km upstream of the Jeziorsko Reservoir, and a tailwater site (CD) 1.5 km downstream of the dam. Both sites were studied for 3 years in the pre-impoundment period (1985,1987) and 15 years after damming (1988,2002). Quantitative electrofishing in spring and autumn assured obtaining yearly average biomass for each population. Most of the data analysis aimed to assess the dam impact on the fish assemblage structure but other accompanying impacts such as discharge manipulations, revetment, different forms of engineering, and water quality improvement in the tailwater and backwater reaches were also discussed. The Kohonen algorithm (self-organizing map, SOM) was used for the analysis, and perfectly separated AB and CD samples into two clusters. Samples from the backwater (AB) proved that this reach of the Warta River had maintained its almost natural character and that fish assemblages had changed moderately, now occupying only five neighbouring hexagons out of a total of 16. In the tailwater (CD), however, because of considerable fluctuations in fish assemblages the SOM produced three subclusters, which engaged nine hexagons: (i) the pre-impoundment period (1985,1987, two hexagons); (ii) 7 years after the definite closure of dam sluices (1988,1994, five hexagons); and (iii) the past 8 years of sampling (1995,2002, two hexagons), when stabilization in the assemblage was observed. The SOM also definitely proved profound changes in fish assemblage composition: most lithophilous species declined and many phytolithophilous and phytophilous species became dominants, particularly in the tailwater site where downstream migration of 0+ of successfully spawned species from the reservoir took place. [source]

Non-direct homing behaviours by adult Chinook salmon in a large, multi-stock river system

M. L. Keefer
Two non-direct homing behaviours, overshoot of natal tributaries and temporary non-natal tributary use, were evaluated for 5150 radio-tagged spring,summer Chinook salmon Oncorhynchus tshawytscha from 40 populations in the large Columbia River system. Over 7 years, 2,44% (mean = 15%) of individuals within each group temporarily entered presumed non-natal tributaries. In addition, many Chinook salmon from lower river tributaries initially travelled 3 to >250 km upstream in the main-stem river beyond confluences with presumed natal tributaries before returning to the natal sites (,overshoot'). Both overshoot and temporary tributary use behaviours declined exponentially with increasing distance from the natal tributary. Non-direct homing also increased later in the season as water temperatures rose and was associated with hatchery origin in some cases. The behaviours may reflect a mix of active searching for olfactory cues from natal sites, behavioural thermoregulation and orientation challenges in a large-river migration corridor transformed by dams and reservoirs. While anadromous salmonid homing is generally accurate and precise, these results indicate that route finding can be non-direct, potentially increasing energetic costs and harvest risks during migration. [source]

Quaternary landscape evolution: a framework for understanding contemporary erosion, southeast Spain

A. E. Mather
Abstract Recent research into the long-term landscape development of a tectonically active terrain in arid SE Spain has revealed the significance of river capture in understanding current landscape instabilities (badlands and landslides). The river capture was initiated at c.100,ka,BP and effected a 90,m base-level change at the point of capture. This stimulated a wave of incision to propagate through the landscape to 20,km upstream of the capture site. The net effect of the associated increase in erosion has been to change valley shapes from broad and shallow to narrow and deep. The associated unloading and steepening of valley sides has led to a focus of landslide activity in lithologies with more unconfined compressive strength (limestones) and a dominance of gullying, piping and badland development in the lithologies with lower unconfined compressive strengths (marls and sands). Post-capture rapid valley widening was initially achieved through landslide development. This form of slope degradation was sustained in the more resistant, joint-controlled lithologies. In weaker lithologies it was superseded by badland development. The elevated sediment fluxes associated with the c.100,ka,BP base-level perturbation will continue into the near future, but are expected to decay, assuming that no additional environmental disturbances occur. The patterns of landscape instability witnessed today are controlled by (1) proximity to the areas affected by the base-level change and (2) the robustness of the local geology. Understanding of this long-term temporal context of the landscape provides a valuable spatial and temporal framework for land system management, facilitating the prediction of future natural trends in landscape stability. Copyright © 2002 John Wiley & Sons, Ltd. [source]