共查询到20条相似文献,搜索用时 15 毫秒
1.
Bradley Drury Emma Rosi-Marshall John J. Kelly 《Applied and environmental microbiology》2013,79(6):1897-1905
In highly urbanized areas, wastewater treatment plant (WWTP) effluent can represent a significant component of freshwater ecosystems. As it is impossible for the composition of WWTP effluent to match the composition of the receiving system, the potential exists for effluent to significantly impact the chemical and biological characteristics of the receiving ecosystem. We assessed the impacts of WWTP effluent on the size, activity, and composition of benthic microbial communities by comparing two distinct field sites in the Chicago metropolitan region: a highly urbanized river receiving effluent from a large WWTP and a suburban river receiving effluent from a much smaller WWTP. At sites upstream of effluent input, the urban and suburban rivers differed significantly in chemical characteristics and in the composition of their sediment bacterial communities. Although effluent resulted in significant increases in inorganic nutrients in both rivers, surprisingly, it also resulted in significant decreases in the population size and diversity of sediment bacterial communities. Tag pyrosequencing of bacterial 16S rRNA genes revealed significant effects of effluent on sediment bacterial community composition in both rivers, including decreases in abundances of Deltaproteobacteria, Desulfococcus, Dechloromonas, and Chloroflexi sequences and increases in abundances of Nitrospirae and Sphingobacteriales sequences. The overall effect of the WWTP inputs was that the two rivers, which were distinct in chemical and biological properties upstream of the WWTPs, were almost indistinguishable downstream. These results suggest that WWTP effluent has the potential to reduce the natural variability that exists among river ecosystems and indicate that WWTP effluent may contribute to biotic homogenization. 相似文献
2.
Daniel Bernet Heike Schmidt-Posthaus Thomas Wahli Patricia Burkhardt-Holm 《Journal of Aquatic Ecosystem Stress and Recovery (Formerly Journal of Aquatic Ecosystem Health)》2000,8(2):143-151
The impact of wastewater effluent from a sewage treatment works (STW) on the health of brown trout held in cages and wild brown trout in a river was investigated. Biochemical, histological, and organismal responses as well as parasite abundances were monitored and then analyzed using multivariate analyses. Stress responses in trout induced by the water quality of the river upstream of the STW were enhanced by the discharge of the STW. For caged fish, the serum chemistry values alkaline phosphatase, blood urea nitrogen, and creatinine, as well as histological indices of gills and liver, were most effective at distinguishing among fish held in river water, a mixture of river water and wastewater, and tap water. For wild fish, total protein, histological liver alterations and abundance of two parasites (sessile peritrichia, Sphaerospora sp.) were the most indicative parameters for discriminating the health of fish between sites upstream and downstream of the STW. Considering the relationships between the measured parameters concurrently, the multivariate discriminant analysis is an effective method to evaluate which combination of parameters provide the best discrimination between the treatment groups. In contrast to the calculation of group differences based on individual responses, the integrated responses of parameters representing different biological levels lead to a more comprehensive assessment of organismal health and a more accurate distinction in differences between treatment groups. 相似文献
3.
Stable isotopes (δ15N and δ13C) were used to assess the changes in exposure and assimilation of sewage-derived nutrients in an aquatic food web following changes in effluent quality over an 8 year period at two municipal wastewater treatment plants (WWTPs) that discharge to the Grand River, in southern Ontario. Upgrades at the Kitchener WWTP started in late 2012 to enhance nitrification, while the Waterloo WWTP had a series of construction issues at the plant that resulted in a deterioration of its effluent quality over the study period (2007–2014). Fish (rainbow darter, Etheostoma caeruleum) and primary consumers (benthic invertebrates) were sampled in the receiving waters associated with each outfall. Upgrades at the Kitchener WWTP resulted in improved effluent quality with total annual ammonia output dropping by nearly sixfold (583–100 t), while the Waterloo WWTP increased its total annual ammonia output by nearly fourfold (135–500 t) over the duration of the study. Downstream of the Kitchener WWTP, the reduction in total ammonia output negatively correlated with changes in δ15N of rainbow darter from being depleted (prior to the upgrade) to reflecting signatures similar to those at the upstream reference site. The biota downstream of the Waterloo WWTP showed the opposite trend, going from slightly enriched, to being depleted relative to the upstream reference sites. δ13C was consistently higher downstream of both WWTPs regardless of changing effluent quality, and annual variability in δ13C was associated with annual river discharge. In a laboratory based dietary switch study conducted with rainbow darter, the isotope half-life in muscle (29 days for δ15N and 33 days for δ13C) were determined and these rapid changes were consistent with responses in muscle of wild fish. This is a unique study that was able to contrast two WWTPs in the same watershed as they underwent major changes in treatment processes. Stable isotopes were very effective as a tool to trace the changes in aquatic biota due to changes in wastewater effluent quality, both improvements and deterioration over time. 相似文献
4.
Fish live in continuous contact with various stressors and antigenic material present within their environments. The impact of stressors associated with wastewater-exposed environments on fish has become of particular interest in toxicology studies. The objectives of this study were to examine potential effects of wastewater treatment plant (WWTP) effluent-associated stressors on innate cytokine expression within the gills of darter species (Etheostoma spp.), using both field and laboratory approaches. Male and female darters (rainbow, greenside, fantail, and johnny darters) were collected upstream and downstream of the Waterloo WWTP in the Grand River, Ontario. Gill samples were collected from fish in the field and from a second subset of fish brought back to the laboratory. Laboratory fish were acutely exposed (96-h) to an environmentally relevant concentration of venlafaxine (1.0 μg/L), a commonly prescribed antidepressant. To assess the impacts of these stressors on the innate immunity of darters, the expression of key innate cytokines was examined. Minor significant effects on innate cytokine expression were observed between upstream and downstream fish. Moderate effects on cytokine expression were observed in venlafaxine-exposed fish compared to their control counterparts however, changes were not indicative of a biologically significant immune response occurring due to the exposure. Although the results of this study did not display extensive impacts of effluent and pharmaceutical exposure on innate cytokine expression within the gills, they provide a novel avenue of study, illustrating the importance of examining potential impacts that effluent-associated stressors can have on fundamental immune responses of native fish species. 相似文献
5.
Using higher organisms in biological early warning systems for real-time toxicity detection. 总被引:3,自引:0,他引:3
W H van der Schalie T R Shedd P L Knechtges M W Widder 《Biosensors & bioelectronics》2001,16(7-8):457-465
Many biological early warning systems (BEWS) have been developed in recent years that evaluate the physiological and behavioral responses of whole organisms to water quality. Using a fish ventilatory monitoring system developed at the US Army Centre for Environmental Health Research as an example, we illustrate the operation of a BEWS at a groundwater treatment facility. During a recent 12-month period, the fish ventilatory system was operational for 99% of the time that the treatment facility was on-line. Effluent-exposed fish responded as a group about 2.8% of the time. While some events were due to equipment problems or non-toxic water quality variations, the fish system did indicate effluent anomalies that were subsequently identified and corrected. The fish monitoring BEWS increased treatment facility engineers' awareness of effluent quality and provided an extra measure of assurance to regulators and the public. Many operational and practical considerations for whole organism BEWS are similar to those for cell- or tissue-based biosensors. An effective biomonitoring system may need to integrate the responses of several biological and chemical sensors to achieve desired operational goals. Future development of an 'electronic canary', analogous to the original canary in the coal mine, could draw upon advances in signal processing and communication to establish a network of sensors in a watershed and to provide useful real-time information on water quality. 相似文献
6.
Matthew E. Kimball Kevin M. Boswell Lawrence P. Rozas 《Wetlands Ecology and Management》2017,25(3):299-312
Estuaries are composed of multiple interconnected habitat types used by transient fish species during their period of estuarine residency. Structural marsh management restricts habitat connectivity and impedes the movement of fishes among these habitat types by limiting access via water control structures (WCSs) between the managed area and the rest of the estuary. While some general information on fish passage rates is available, species-specific information on passage through WCSs is lacking for salt marsh fishes. We monitored tagged fishes from March 2012 through November 2013 using passive integrated transponder antenna arrays at two identical WCSs in the Calcasieu Lake estuary, Louisiana, USA, to assess the effect of slotted WCSs on fish behavior. A total of 420 individuals of 15 species was tagged and released at the WCSs; of these, 145 individuals representing 11 species were later detected at the WCSs. Five species comprised most (93%) of the detected individuals: Elops saurus (n = 60), Mugil cephalus (n = 43), Sciaenops ocellatus (n = 20), Pogonias cromis (n = 7), and Ariopsis felis (n = 5). Passage rates were low, with most of the observed fishes (n = 80) passing only once through the structures. Other than E. saurus, which was only observed migrating out of the managed marsh, no clear pattern in swimming direction was observed for the other species. Detected species were all present primarily during the summer and fall, however, diel activity at the structures varied by species. The WCSs in our study area appeared to attract and congregate fishes, functioning more like ecological hotspots, rather than simply facilitating fish passage. 相似文献
7.
Abstract Habitat availability is often regarded as the primary factor that limits population and community recovery in degraded ecosystems, and physical habitat is thus often targeted in restoration. The identification of which habitat(s) to attempt to restore is a critical step in the restoration process, but one for which there is often a paucity of useful information. Here we examine the distribution of fish in three lowland streams in Victoria, Australia, that have been degraded by severe sedimentation. We aim to identify habitats that are associated with high abundances of native fish, and that thus might be appropriate to target in habitat restoration. Associations between native fish abundances and physical habitat characteristics were examined at three spatial scales (among streams, among sites and within sites) to determine the types of habitat to which fish respond, and the scales over which these responses occur. Of the four species of native fish found in the streams, three (Galaxias olidus Günther, Gadopsis marmoratus (Richardson) and Nanoperca australis Günther) showed significant habitat associations at small spatial scales (i.e. within sites). In particular, these species were generally found in deeper water, and in close proximity to cover (typically either coarse or fine woody debris or vegetation). Differences in habitat availability among sites and streams were less influential, except in the case of G. marmoratus, which was completely absent from both the ephemeral streams. Although our results suggest that these species collectively respond to habitat at several spatial scales, fish distributions were allied to the presence of habitat structure at the scale of metres, the smallest spatial scale examined. We hypothesize that fish abundances are currently limited by the low availability of habitat at these small spatial scales. It may therefore be possible to increase fish abundances in these creeks by augmenting the amount of available habitat via stream restoration. 相似文献
8.
Detailed analyses of habitat associations with rare species are typically constrained by limited sample size and the availability
of habitat data. The dense spatial coverage of stream sampling by the Maryland Biological Stream Survey provides ample data
to quantitatively examine correlations between habitat and rare species distributions. The shield darter, Percina peltata, has a widespread distribution on the Atlantic Slope of the United States, but is uncommon throughout its range in Maryland.
Associations of in situ physical habitat, water chemistry, and alterations in landscape with shield darter presence in the
Eastern Piedmont physiographic province in Maryland were examined. Shield darter occurrence was associated with larger sized
streams in concordance with the species’ known ecology. Shield darter distribution was further associated with stream segments
with deep riffle habitats with diverse velocities, low concentrations of chloride and sulfate, low levels of urbanization
in upstream catchments, and several pollution intolerant fish species. Although the exact mechanism of the effects is not
clear, results indicate that the shield darter is sensitive to urban development and habitat and water quality alteration
that typically accompanies urbanization. Shield darter conservation in Maryland necessitates the protection and restoration
of minimally urbanized watersheds where they are known to occur. The results from this study indicate that habitat information
on rare species may be important in elucidating important habitat associations that are not evident via examination of community
level data. 相似文献
9.
N. C. Ferreira R. M. Guereschi C. Machado C. A. Lopes A. P. O. Nuñer 《Journal of fish biology》2017,90(4):1265-1282
This study examined the fish communities of Peri Lagoon in southern Brazil to aid in the development of an effective management plan because the area is under threat from human activities. Sampling of fish fauna, ichthyoplankton and limnological data were compared between sites, differing by habitat type and characteristics such as depth, substratum composition and vegetation type. Results were significantly related to site, with the highest diversity and abundance recorded at shallow vegetated sites. A total of 14 fish species were recorded throughout the lagoon, with the most abundant being Hyphessobrycon luetkenii. Of the 14 species, half were sampled at their larval stage, suggesting a healthy and protected system. Significantly more larvae and eggs were collected during colder months (autumn to winter) and at sites closer to stream flow, possibly owing to increased food sources and habitat protection. This study highlights the importance of Peri Lagoon as a nursery ground for a wide range of fish species, providing essential information for incorporation into the future protection of fish stocks throughout Brazil. 相似文献
10.
Quenton M. Tuckett Jared L. Ritch Katelyn M. Lawson Jeffrey E. Hill 《Biological invasions》2017,19(1):223-237
The Tampa Bay region of Florida exhibits the highest concentration of ornamental aquaculture facilities in the USA. Because of the diversity of aquaculture products (~800 species and varieties) and extensive production history (began in the 1930s and 1940s), this region could be a hotspot for escaped ornamental fish. We evaluated the scope of ornamental fish invasions in this region by examining (1) escape vectors and (2) the distribution of escaped fish. We investigated potential pathways of fish escape including theft/vandalism, fish transport, bird carry-off, and through effluent discharge. Fish were sampled at the effluent discharge and continued into the surrounding environment. The dominant escape vector was through farm effluents; there was no evidence that theft/vandalism, fish transport, or bird carry-off contributed to fish escape. Most captured fish were natives, especially the ubiquitous Eastern Mosquitofish (Gambusia holbrooki). Ornamental species and varieties were also captured, especially cichlids and poeciliids such as the Green Swordtail (Xiphophorus hellerii) and Southern Platyfish (Xiphophorus maculatus). Ornamental fish were often found in the immediate vicinity of fish farms but were rarely captured in the surrounding environment. Catch per unit effort and ornamental fish diversity declined when moving away from the aquaculture facility effluent and was reduced at sites with a detention pond. The observed fish distribution might be due to relatively cold water in sub-tropical Florida, predatory fish in the environment, and additional factors related to the physical or biological habitat. Ultimately, few ornamental fishes have established in this region despite a long period of extensive culture. 相似文献
11.
Influences of low-head dams on the fish assemblages in the headwater streams of the Qingyi watershed, China 总被引:1,自引:0,他引:1
Yunzhi Yan Hong Wang Ren Zhu Ling Chu Yifeng Chen 《Environmental Biology of Fishes》2013,96(4):495-506
The influences of low-head dams on the fish assemblages were examined in this study, using fish data collected in six treatment and five reference sites at three low-head dams in the headwater streams of the Qingyi watershed, China. Comparing with those in the reference sites, local habitat variables were significantly altered by low-head dams in the treatment sites, involving wider channel (only in the impoundment area), deeper water and slower flow. Fish species richness varied significantly across seasons, not across site categories, suggesting that these low-head dams did not alter species richness. However, significant decreases in fish abundance and density were observed in the impoundment areas immediately upstream of dams, but not in the plunge areas downstream. Fish assemblage structures kept relative stability across seasons, and their significant difference between-site was only observed between the impoundment areas and the sites far from dams upstream. This variation in assemblage structures was due to the differing relative abundance of some co-occurring species; more lentic but less lotic fish was observed in the impoundment areas. The spatial and temporal patterns of fish assemblages were correlated with local habitat in this study area. Wetted width had negative correlation with fish species richness, abundance and density, respectively. Water temperature also positively affected species richness. In addition, wetted width, water depth, current velocity and substrate were the important habitat variables influencing assemblage structures. Our results suggested that, by modifying local habitat characteristics, low-head dams altered fish abundance and density in the impoundment areas immediately upstream of dam, not in the plunge areas immediately downstream, and thereby influenced fish assemblage structures in these stream segments. 相似文献
12.
MARGUERITE A. XENOPOULOS CHRISTOF SCHNEIDER DAELYN A. WOOLNOUGH 《Global Change Biology》2011,17(4):1720-1732
The role of climate‐related disturbances on complex host–affiliate relationships remains understudied, largely because affiliate species vary in host use and are often differentially susceptible to disturbance relative to their hosts. Here we report the first set of host–affiliate species–discharge relationships (SDR) in freshwater and examine how anticipated shifts in water availability (flow) will impact coextirpations. We used SDR for freshwater mussels and fish across 11 regions (over 350 rivers) in the continental United States that we coupled to future water availability (2070) to model mussel and fish coextirpations. We also used river‐specific host–affiliate matrices (presence–absence) to evaluate how host‐specificity (mean number of hosts used by an affiliate) and host‐overlap (extent to which affiliates share hosts) relate to extirpation vulnerability. We found that the strength and predictability of SDR models vary geographically and that mussels were more susceptible to flow alterations than fish. These patterns of extirpations were strongest in the southeast where: (1) flow reductions are expected to be greatest; (2) more species are lost per unit flow; (3) and more mussels are expected to be lost per unit of fish. We also found that overall mussel losses associated with reduction in habitat (water availability) were greater than those associated with loss of fish hosts which we assumed to be a function of host redundancy. These findings highlight the utility of SDR as a tool for conservation efforts but they also demonstrate the potential severity of reductions in mussel and fish richness as consequence of climate change and water use. Mussels provide key ecosystem services but face multiple pronged attacks from reductions in flow, habitat, and fish hosts. These losses in biodiversity and ecosystem functions can translate into major effects on food webs and nutrient recycling. 相似文献
13.
Relationships between fish assemblages, macrophytes and environmental gradients in the Amazon River floodplain 总被引:6,自引:0,他引:6
During the flood season of 1992–1993, 139 species of fishes were collected from a floodplain lake system in the central Amazon Basin. Fish species distribution was examined relative to abiotic variables in seven vegetation strata on Marchantaria Island, Solimões River. Both environmental variables and species distributions were influenced by a river channel to floodplain-interior gradient. Species diversity was significantly higher in vegetated areas than in unvegetated areas, with deeper water Paspalum repens stands harbouring the highest diversity. As a result, species richness and catches were positively related to habitat complexity, while catch was also negatively related to dissolved oxygen (DO) and water depth. Low DO and shallow waters appeared to act as a refuge from predation. Fish assemblages were related to water chemistry, but species richness was not. Canonical correspondence analysis provided evidence that floodplain fish assemblages formed by the 76 most common species were influenced by physical variables, macrophyte coverage and habitat complexity, which jointly accounted for 67% of the variance of fish species assemblages. Omnivores showed no pattern relative to the river channel to floodplain-interior gradient while detritivores were more likely to be found at interior floodplain sites and piscivores closer to the river. Piscivores could be further separated into three groups, one with seven species associated with free-floating macrophytes in deep water, a second with five species found in shallow waters with rooted grasses and a third with six open water orientated species. The results suggest that fish assemblages in the Amazon floodplain are not random associations of species. 相似文献
14.
Seasonal microhabitat selection by sympatric young Atlantic salmon and brown trout was studied by diving. Both species, especially Atlantic salmon, showed seasonal variation with respect to surface and mean water velocities and depth. This variation is partly attributed to varying water flows and water temperatures. In winter the fish sought shelter in the substratum. A spatial variation in habitat use along the river due to different habitat availabilities was observed. Both species occupied habitats within the ranges of the microhabitat variables, rather than selecting narrow optima. It is hypothesized that the genetic basis allows a certain range to the behavioural response. Microhabitat segregation between the two species was pronounced, with brown trout inhabiting the more slow-flowing and partly more shallow stream areas. Atlantic salmon tolerated a wider range of water velocities and depths. Habitat suitability curves were produced from both species. It is suggested that habitat suitability curves that are based on observations of fish occupancy of habitat at median or base flow may not be suitable in habitat simulation models, where available habitat is projected at substantially greater water flows. 相似文献
15.
M. Scholten 《Zeitschrift fur angewandte Ichthyologie》2003,19(5):265-277
The assessment of fish densities using point abundance sampling by electro‐fishing requires information about the size of the sample area. For electro‐fishing the effective fishing range depends on biological effects such as species and length of fish as well as physical effects like conductivity of water or substrate type. The present study investigates systematically the impact of conductivity and substrate type on the extension of the electrical field of a battery‐powered electro‐fishing gear (DEKA 3000, Marsberg, Germany), modified for larval and juvenile fishes. Threshold values for galvanotaxis were examined for juvenile fishes of five species in terms of current densities. Based on 71 experiments a general function relating body length to current density threshold values was developed. Optimal electrical current flow periods of 10 s were determined. For three different substrate types (gravel, sand, mud) a formula has been developed to quantify biological and physical effects on the effective fishing range. Each equation included information on the length of fish and the ambient conductivity. An increase in the effective fishing range of about 10% every 0.1 mS cm?1 was established. Reduction of the fishing range over muddy substrate was about 20–30% compared with coarse gravel or sand. This study provides a sufficient tool to calculate area‐related densities of larval and juvenile fishes in different habitat types of a large river system using point abundance sampling by electro‐fishing. Finally, calculated fish densities were evaluated by different types of fishing gear. 相似文献
16.
M. J. Kennard B. J. Pusey A. H. Arthington B. D. Harch S. J. Mackay 《Hydrobiologia》2006,572(1):33-57
Multivariate predictive models are widely used tools for assessment of aquatic ecosystem health and models have been successfully
developed for the prediction and assessment of aquatic macroinvertebrates, diatoms, local stream habitat features and fish.
We evaluated the ability of a modelling method based on the River InVertebrate Prediction and Classification System (RIVPACS)
to accurately predict freshwater fish assemblage composition and assess aquatic ecosystem health in rivers and streams of
south-eastern Queensland, Australia. The predictive model was developed, validated and tested in a region of comparatively
high environmental variability due to the unpredictable nature of rainfall and river discharge. The model was concluded to
provide sufficiently accurate and precise predictions of species composition and was sensitive enough to distinguish test
sites impacted by several common types of human disturbance (particularly impacts associated with catchment land use and associated
local riparian, in-stream habitat and water quality degradation). The total number of fish species available for prediction
was low in comparison to similar applications of multivariate predictive models based on other indicator groups, yet the accuracy
and precision of our model was comparable to outcomes from such studies. In addition, our model developed for sites sampled
on one occasion and in one season only (winter), was able to accurately predict fish assemblage composition at sites sampled
during other seasons and years, provided that they were not subject to unusually extreme environmental conditions (e.g. extended
periods of low flow that restricted fish movement or resulted in habitat desiccation and local fish extinctions). 相似文献
17.
The conservation and management of inland fish and freshwater ecosystems immensely contribute to global sustainable development. The existing ‘Protected Area’ (PA) network does not represent freshwater resources well and seldom considers its fish communities, while designating PAs. A study was undertaken to quantitatively assess the role played by the three terrestrial PAs (IUCN category IV) in conserving fish diversity and preserving habitat quality in the river reaches bordering the three PAs of the river Pranhita. It is a unique river system in the Indian Deccan Plateau in terms of fish diversity and community structure. Field surveys were conducted during the non-monsoon and monsoon seasons in 2020–21, that recorded 53 species including endemic and threatened fishes from river Pranhita, which represent more than one-third the number of fish species of Telangana state. The higher diversity and lower dominance index value (p < 0.01) reported in PAs compared to Eco Sensitive Zones and unprotected areas during the non-monsoon season indicate the role of intact physical habitat in providing refuges to the fish species in monsoon dependent tropical rivers. The optimal water quality revealed no significant difference (p > 0.0001) between protected and unprotected river reaches, and healthy biotic integrity assessed on the basis of fish community structure was attributed to the contiguous flow and less anthropogenic disturbance. This study supports that it can be considered as a representative zone for the conservation and protection of indigenous and endemic fish species of the Godavari Basin. The results concluded that the scope of the terrestrial PA network in India could be potentially extended to their bordering aquatic ecosystems, especially rivers to maintain pristine habitat conditions and conserve the fish genetic resources to ensure the flow of ecosystem services. 相似文献
18.
长江安庆段仔稚鱼群落特征调查研究 总被引:1,自引:0,他引:1
安庆江段是长江下游重要渔业资源水域之一, 为了解该江段仔稚鱼群落特征及与环境因子的关系, 于2016年4月17日至8月15日对安庆江段仔稚鱼进行了逐日调查。结果显示: 研究共采集仔稚鱼个体92160尾, 鉴定90457尾, 隶属于7目11科49种, 其中鲤科(Cyprinidae)种类数居第一, 32种, 尾数占比为90.16%; 鰕虎鱼科(Gobiidae)居第二, 3种, 尾数占比为5.71%。在生态类型及产卵方式上, 淡水定居性鱼类和产漂流性卵鱼类数量占比最大, 分别为87.57%和88.30%。贝氏?(Hemiculter bleekeri)是该江段第一优势种, 数量占比44.53%, 其余优势种为?(Hemiculter leucisculus, 占比14.21%)、银鲴(Xenocypris argentea, 占比8.11%)、子陵吻鰕虎(Rhinogobius giurinus, 占比5.60%)、飘鱼(Pseudolaubuca sinensis, 占比4.75%)、似鳊(Pseudobrama simoni, 占比4.13%)、寡鳞飘鱼(Pseudolaubuca engraulis, 占比4.50%)、鳊(Parabramis pekinensis, 占比2.63%)、刀鲚(Coilia nasus, 占比1.89%)、鲢(Hypophthalmichthys molitrix, 占比1.57%)。仔稚鱼丰度出现4次明显的高峰时期, 第一次在5月1日, 后面三次集中出现在6月中下旬, 分别为1127.00、1608.44、1568.35 和1202.94 ind./100 m3。通过冗余分析(RDA)表明, 影响安庆江段仔稚鱼丰度的主要环境因子为水流量、水位、透明度(P<0.05), 大多数仔稚鱼丰度与水流量、水位呈现负相关, 与透明度呈现正相关, 可能与该年份过高的水流量、水位有关。研究表明, 安庆江段的仔稚鱼种类较丰富, 但主要以小型鱼类为主, 且经济性仔稚鱼类占比小。研究初步探明了安庆江段的仔稚鱼资源状况, 其结果为安庆鱼类早期资源进一步研究提供基础资料, 同时也为渔业资源保护策略制定提供科学依据。 相似文献
19.
Feeding of tropical freshwater fishes: seasonality in resource availability and resource use 总被引:1,自引:0,他引:1
Summary Food resources in the environment and in the diets of small fish inhabiting two water bodies in a tropical savanna were studied during both wet and dry seasons. During the wet season (high water, abundant food) most fish species in both habitats fed predominantly on vegetation-dwelling invertebrates. Most fish species switched to alternative foods (algae and detritus) following the drastic decline in invertebrate food available towards the end of the dry season. In one habitat, this change in diet was accompanied by an increase in the volume of food intake. In the second habitat, only two larger species foraged intensively, while smaller species showed low food intake or almost ceased feeding. These differences may be explained by the high risk of predation for small fish in the second habitat. Dietary overlaps among fish species were high at the end of the dry season and moderate in the wet season. However, critical analysis of such factors as food abundance, the size and number of shared prey, and diet breadth showed that all significant overlaps were ecologically unimportant i.e. there was only weak competition for food. 相似文献
20.
Daniel Hayes Michael Jones Nigel Lester Cindy Chu Susan Doka John Netto Jason Stockwell Bradley Thompson Charles K. Minns Brian Shuter Nicholas Collins 《Reviews in Fish Biology and Fisheries》2009,19(3):295-312
One of the major challenges facing fishery scientists and managers today is determining how fish populations are influenced
by habitat conditions. Many approaches have been explored to address this challenge, all of which involve modeling at one
level or another. In this paper, we explore a process-oriented model approach whereby the critical population processes of
birth and death rates are explicitly linked to habitat conditions. Application of this approach to five species of Great Lakes
fishes including: walleye (Sander vitreus), lake trout (Salvelinus namaycush), smallmouth bass (Micropterus dolomieu), yellow perch (Perca flavescens), and rainbow trout (Onchorynchus mykiss), yielded a number of insights into the modeling process. One of the foremost insights is that processes determining movement
and transport of fish are critical components of such models since these processes largely determine the habitats fish occupy.
Because of the importance of fish location, an individual-based model appears to be a nearly inescapable modeling requirement.
There is, however, a paucity of field-based data directly relating birth, death, and movement rates to habitat conditions
experienced by individual fish. There is also a paucity of habitat information at a fine temporal and spatial scale for many
important habitat variables. Finally, the general occurrence of strong ontogenetic changes in the response of different life
stages to habitat conditions emphasizes the need for a modeling approach that considers all life stages in an integrated fashion. 相似文献