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1.
Intense development of the coastal zone in Singapore has resulted in the degradation of much of the marine ecosystem. In order to restore and enhance fish communities of denuded areas, an artificial reef consisting of a tyre reef and a concrete reef, was established in the vicinity of the southern islands of Singapore. Results from fish visual censuses after the establishment of the artificial reef indicated an increase in numbers of juveniles and adults. A total of 37 and 32 fish species were recorded over a period of 1/2 years at the concrete and tyre reefs respectively. The dominant fish families were Pomacentridae, Labridae, Chaetodontidae, Apogonidae, Gobiidae and Nemipteridae. The artificial reefs also serve as a nursery ground for some species (e.g. Neopomacentrus sp.) which are important primary consumers of algae on natural reefs. Greater numbers of target (food-important) fishes were observed at the concrete reef while the tyre reef harboured more juveniles and smallersized adults. The results indicate that the concrete modules were more effective than the tyre reef in terms of fish abundance per unit volume. Such structures can enhance the biological resources of relatively unproductive areas. 相似文献
2.
Synopsis Behavioral preference for a structured habitat (artificial seagrass) by juvenile walleye pollock,Theragra chalcogramma, was tested in controlled laboratory experiments. We monitored position of fish in 2000 1 tanks with and without artificial
seagrass present in one half of the tank. In addition, we exposed walleye pollock to a predator model, assessing their response
when a grass plot was available or unavailable as a potential refuge. In the absence of predators, the fish avoided the artificial
seagrass, displaying a preference for the open water side of the experimental tanks. In the presence of a predator model,
however, juvenile walleye pollock readily entered the artificial seagrass plots. In addition, they often remained in the grass
canopy in proximity to the predator instead of moving out of the grass to avoid the predator (when no grass was present they
consistently moved to the opposite side of the tank from the predator). The behavioral choices exhibited in this study suggest
that juvenile walleye pollock modify habitat selection in response to perceived predation risk, and recognize the structure
provided by artificial seagrass as a potential refuge. 相似文献
3.
The non-native tunicates Didemnum vexillum, Ciona savignyi, and Styela clava are of concern to resource managers of Puget Sound, Washington, USA because they have been shown to threaten native species diversity and shellfish aquaculture in other regions. Invasive tunicates in Puget Sound occur mainly on man-made structures such as floating docks and aquaculture facilities. We conducted studies of the three species of concern and a fourth introduced tunicate, Botrylloides violaceus, that occur on these structures to evaluate their effects on mussels and native invertebrate communities. Because most studies of community effects of tunicates have dealt with sessile fouling organisms, we focused instead on epibenthic organisms such as meiofaunal harpacticoid copepods and macrofaunal polychaetes and amphipods that are known to be important prey for juvenile salmon and other small fish. Similar studies have shown mixed results, with negative, positive, or no effects depending on the species. We also found few community-level effects. Abundances of several species were lower when tunicates were present, but only at some of the sites. Several other species, including a non-native isopod, were significantly more abundant in the presence of tunicates. However, in most cases results were not statistically significant and more intensive, controlled sampling or experiments may be needed to demonstrate any consistent tunicate effects. Although invasive tunicates cause problems for mussel growers elsewhere, we did not find negative effects on mussels at four sites in Puget Sound. Given the large impacts known to accompany tunicate invasions elsewhere and their relatively recent invasions into Puget Sound, monitoring of their populations and effects should continue in the region. 相似文献
4.
A fourteen-year overview of the fish assemblages and yield of the two oldest Algarve artificial reefs (southern Portugal) 总被引:3,自引:0,他引:3
Artificial reefs have been deployed worldwide for the last three decades in response to problems concerning coastal resources, ecosystems and fisheries. In many countries they have became important elements of integrated fisheries management plans. In Portugal two artificial reef systems (ARSs) were deployed by the Portuguese Institute of Marine Research (IPIMAR) in 1990, in the southern coast (Algarve). They were located off Faro and Olhão, over different sea-bottom types and located at different distances from the coastline. To analyse the effect of ARSs deployment on local fish assemblages and to evaluate their effectiveness in terms of mean fishing yields and mean number of species caught, fishing surveys have been conducted over 14 years (256 net sets) using a gillnet to sample the ARS of Faro and Olhão and respective control sites. The fishing yields from the ARs continually exceeded those from the control sites, in both the mean number of species caught and the mean CPUE in weight (1.8–2.6 times); both were higher at Faro. Moreover, the comparison between fish assemblages from the ARS and respective control sites showed that the deployment of the man-made structures did not change the composition of the fish assemblages caught by the gill nets, or the equilibrium of the community, since the relative proportion of the different functional groups of fish remained stable. The ARSs are a useful management tool on the Algarve coast, enhancing and diversifying the catches, thus contributing to improved local artisanal fisheries, which play a major role in this region. 相似文献
5.
Spatial and temporal patterns in fish assemblages of upper coastal plain streams, Mississippi, USA 总被引:1,自引:1,他引:0
We assessed spatial, seasonal, and annual variation in fish assemblages over 17 months in three small- to medium-sized, incised streams characteristic of northwestern Mississippi streams. We sampled 17 962 fish representing 52 species and compared assemblages within and among streams. Although annual and seasonal variability in assemblage structure was high, fish assemblages maintained characteristics unique to each stream. High variability in fish catch-per-unit-effort (CPUE) was exemplified in one site where total CPUE increased an order of magnitude from July 1993 to 1994. Species turnover and percent dissimilarity were often higher seasonally than annually, consistent with a period of change in spring to early summer and a return to similar species compositions between summers. Temporal variability was also high at the individual species level, and no species were classified as 'stable'. We found little evidence for correlation between changes in fish assemblage structure and measured habitat conditions. The fish characteristics fit the profile of 'colonizing assemblages', which probably resulted from both natural and anthropogenic causes. Flashy hydrographs , created in part by stream channelization and incision and watershed deforestation, may play a large role in structuring these fish assemblages. Extreme interannual variability in assemblages in the absence of detectable habitat change has important implications for the statistical power of fish monitoring programs designed to detect trends in fish assemblages over time. 相似文献
6.
Robert K. Howard 《Environmental Biology of Fishes》1989,24(2):93-104
Synopsis Extensive limestone reefs are a characteristic feature of much of the coastline of Western Australia, and potentially represent a major habitat feature influencing the structure of the coastal fish community. The structure and temporal dynamics of the fish fauna and its relationships to nearshore patch reefs and surrounding habitat near Dongara, Western Australia, were examined using (1) diel gill-netting and (2) quantitative rotenone sampling of enclosed areas of substratum. Long-term and day-to-day variability of the fauna was low. Dominant species of gill-net collections were either associated with reefs or occurred in similar abundances at both reefs and surrounding sand/seagrass flats. The overall abundance, number of species and biomass of netted fishes was higher around reefs. Rotenone collections of the more sedentary species showed a similar pattern, but suggested, however, that a simple reef versus surrounding sand and seagrass habitat comparison is complicated by the canopy-forming seagrass Amphibolis that occurs on reef tops. Time of day had an important effect on overall fish abundance and number of species, with peaks occurring at crepuscular periods. This reflected dusk and dawn activity peaks of a dominant species rather than overlapping activities of many diurnal and nocturnal species. Diel switches between reef-edge habitat and surrounding sand/seagrass flats were uncommon despite expectations (based on literature examples) that patch reefs would function primarily as sheltering habitats and surrounding non-reef areas act as foraging habitat. High catches at reef-edge sites suggest that the majority of fishes forage on or near limestone patch reefs. Fish densities of around 0.8 individuals per m-2 of bottom on these Western Australian reefs are relatively high in comparison to visual census estimates obtained for temperate reef systems in South Australia and New Zealand, but similar to those obtained using comparable netting methods in temperate Australian seagrass systems. 相似文献
7.
A. B. Gill 《Journal of fish biology》2003,63(S1):105-116
Over a number of decades the process of prey choice has been investigated using fishes as model predators. Using fishes for the model has allowed the proximate factors that determine how a mobile predator finds and chooses to eat the prey encountered within a variable 3‐D environment to be estimated. During prey choice a number of constraints exist, in particular most fish predators will eat their prey whole thus their jaws and gut create functional limitations once a prey has been attacked. By considering the relationship between the size of the prey and the predator's feeding apparatus and feeding motivation this study explores the link between mechanistic studies and theoretical, optimal foraging based predictions. How the prediction of prey choices made by the fish following prey encounter can be reconciled with what is likely to be found in the fish's stomach is discussed. This study uses a progression of empirical examples to illustrate how the limits of functional constraints and prey choice at different stages of motivation to feed can be taken into account to improve predictions of predator prey choice. 相似文献
8.
Derelict ships are commonly deployed as artificial reefs in the United States, mainly for recreational fishers and divers.
Despite their popularity, few studies have rigorously examined fish assemblages on these structures and compared them to natural
reefs. Six vessel-reefs off the coast of southeast Florida were censused quarterly (two ships per month) to characterize their
associated fish assemblages. SCUBA divers used a non-destructive point-count method to visually assess the fish assemblages
over 13- and 12-month intervals (March 2000 to March 2001 and March 2002 to February 2003). During the same intervals, fish
assemblages at neighboring natural reefs were also censused. A total of 114,252 fishes of 177 species was counted on natural
and vessel-reefs combined. Mean fish abundance and biomass were significantly greater on vessel-reefs in comparison to surrounding
natural reef areas. Haemulidae was the most abundant family on vessel-reefs, where it represented 46% of total fish abundance.
The most abundant family on natural reefs was Labridae, where it accounted for 24% of total fish abundance. Mean species richness
was significantly greater on vessel-reefs than neighboring natural reefs and also differed among vessel-reefs. Both mean fish
abundance and mean species richness were not significantly different between natural reefs neighboring vessel-reefs and natural
reefs with no artificial structures nearby. This suggests the vessel-reefs are not, in general, attracting fish away from
neighboring natural reefs in our area. Additionally, economically important fish species seem to prefer vessel-reefs, as there
was a greater abundance of these species on vessel-reefs than surrounding natural reef areas. Fish assemblage structure on
natural versus artificial reefs exhibited a low similarity (25.8%). Although no one species was responsible for more than
6% of the total dissimilarity, fish assemblage trophic structure differed strikingly between the two reef types. Planktivores
dominated on vessel-reefs, accounting for 54% of the total abundance. Conversely, planktivores only made up 27% of total abundance
on natural reefs. The results of this study indicate vessel-reef fish assemblages are unique and that these fishes may be
utilizing food resources and habitat characteristics not accessible from or found at natural reefs in our area. Production
may also be occurring at vessel-reefs as the attraction of fish species from nearby natural reefs seems to be minimal.
Electronic supplementary material Supplementary material is available for this article at and accessible for authorised users 相似文献
9.
Galaxias maculatus (small puyen) is an abundant native fish distributed in lakes and rivers of the Patagonia, and it is the frequent prey of other fishes, fish-eating birds, and mammals. Previous studies have shown that it is parasitized by 33 metazoan species and that the richness and composition of the parasite communities vary between lakes. The aim of the present work was to analyze the relationship between the composition of fish assemblages and the helminth component community structure of G. maculatus . Ten environmentally similar, small, shallow lakes, belonging to the Nahuel Huapi Lake basin, were chosen because of the differences in the native fish assemblages. Parasite community structure in G. maculatus varied according to the fish assemblage of each lake. The presence of the piscivorous fish Percichthys trucha regularly produced variations in the composition and richness at the component and infracommunity levels, as well as the percentage of autogenic parasite species in G. maculatus . 相似文献
10.
By R. L. Sherman D. S. Gilliam R. E. Spieler 《Zeitschrift fur angewandte Ichthyologie》1999,15(3):116-121
Small concrete artificial reef modules (hemisphere-shaped, approximately 1.3 m diameter, 1 m high) were placed at two sites, eight modules per site. The sites were in 7 m and 21 m of water, 1.6 km apart, off the coast of southeast Florida, USA. The reefs were censused monthly for fish over a 19-month period. Species, number of fish, and estimated total length of each individual were recorded by divers using SCUBA. After the monthly census, all fish were removed from the reefs with a piscicide. A total of 88 species were recorded in the study, with significantly greater diversity on the deep reefs (monthly mean of 7.6 versus 3.0 shallow, P < 0.001, anova ). There were also significantly more biomass (calculated from length), and more large fish (>5 cm) on the reefs at 21 m than at 7 m (P < 0.001). There were more small fish at the shallow site (P < 0.05). Although it is not clear what variable(s) associated with the two depths is responsible for the differences, these results highlight the potential differences in artificial reef and ambient environment interactions within a localized area. 相似文献
11.
Robert L. Vadas Jr. 《Environmental Biology of Fishes》1990,27(4):285-302
Synopsis Food webs for 15 freshwater ecosystems in North America are reconstructed, based upon fish feeding habits in these ecosystems and established trophic categorizations for aquatic invertebrates. My own research in Goose Creek, Virginia, as well as literature data, provided the necessary information. One property of theoretical interest for food webs, namely omnivory, is examined, and the results are related to various topics more typically studied by freshwater fish ecologists, including predator-prey regulation, optimal foraging theory, and tropho-dynamics. The data indicate that omnivory is often important in freshwater ecosystems, such that fish may not always control the abundance of their prey. It is emphasized that knowledge of omnivory patterns can provide important insights into community structure and function in freshwater ecosystems. 相似文献
12.
Peter M. Chapman 《Hydrobiologia》1987,155(1):249-258
Respiration rate measurements were conducted with the marine oligochaete Monopylephorus cuticulatus Baker and Brinkhurst to determine the sublethal toxicity of sediments collected from Puget Sound, Washington. Worms were exposed to elutriates prepared from centrifuged sediment slurries. Standard respiration rates were measured at high dissolved oxygen levels for each sample tested and were compared with control and other test results. A total of 97 sediment samples were tested; 40 samples demonstrated significant respiration effects (elevation or depression). Comparison with results of other tests conducted at the same stations or geographic locations (genotoxicity to fish cells, lethality to sensitive species, reproductive impairment tests) indicated very good agreement on broad scale toxicity patterns at different geographical areas, and that respiration measurements effectively determined sublethal toxicity of sediments. This study represents the first application of respiration measurements as a sublethal toxicity test for field-collected sediments. 相似文献
13.
Are artificial reefs surrogates of natural habitats for corals and fish in Dubai,United Arab Emirates? 总被引:1,自引:0,他引:1
Artificial reefs are often promoted as mitigating human impacts in coastal ecosystems and enhancing fisheries; however, evidence
supporting their benefits is equivocal. Such structures must be compared with natural reefs in order to assess their performance,
but past comparisons typically examined artificial structures that were too small, or were immature, relative to the natural
reefs. We compared coral and fish communities on two large (>400,000 m3) and mature (>25 year) artificial reefs with six natural coral patches. Coral cover was higher on artificial reefs (50%)
than in natural habitats (31%), but natural coral patches contained higher species richness (29 vs. 20) and coral diversity
(H′ = 2.3 vs. 1.8). Multivariate analyses indicated strong differences between coral communities in natural and artificial habitats.
Fish communities were sampled seasonally for 1 year. Multivariate fish communities differed significantly among habitat types
in the summer and fall, but converged in the winter and spring. Univariate analysis indicated that species richness and abundance
were stable throughout the year on natural coral patches but increased significantly in the summer on artificial reefs compared
with the winter and spring, explaining the multivariate changes in community structure. The increased summer abundance on
artificial reefs was mainly due to adult immigration. Piscivores were much more abundant in the fall than in the winter or
spring on artificial reefs, but had low and stable abundance throughout the year in natural habitats. It is likely that the
decreased winter and spring abundance of fish on the artificial reefs resulted from both predation and emigration. These results
indicate that large artificial reefs can support diverse and abundant coral and fish communities. However, these communities
differ structurally and functionally from those in natural habitats, and they should not be considered as replacements for
natural coral and fish communities. 相似文献
14.
Juvenile reef fish communities represent an essential component of coral reef ecosystems in the current focus of fish population
dynamics and coral reef resilience. Juvenile fish survival depends on habitat characteristics and is, following settlement,
the first determinant of the number of individuals within adult populations. The goal of this study was to provide methods
for mapping juvenile fish species richness and abundance into spatial domains suitable for micro and meso-scale analysis and
management decisions. Generalized Linear Models predicting juvenile fish species richness and abundance were developed according
to spatial and temporal environmental variables measured from 10 m up to 10 km in the southwest lagoon of New Caledonia. The
statistical model was further spatially generalized using a 1.5-m resolution, independently created, remotely sensed, habitat
map. This procedure revealed that : (1) spatial factors at 10 to 100-m scale explained up to 71% of variability in juvenile
species richness, (2) a small improvement (75%) was gained when a combination of environmental variables at different spatial
and temporal scales was used and (3) the coupling of remotely sensed data, geographical information system tools and point-based
ecological data showed that the highest species richness and abundance were predicted along a narrow margin overlapping the
coral reef flat and adjacent seagrass beds. Spatially explicit models of species distribution may be relevant for the management
of reef communities when strong relationships exist between faunistic and environmental variables and when models are built
at appropriate scales. 相似文献
15.
The Migjorn artificial reef (MAR) was deployed in the summer of 1990 and is made by 48 concrete blocks set 30 m deep on a
sea bed of sand with a small proportion of Posidonia oceanica (L.) Delile meadow. Visual censuses of blocks on both substrata
were carried out during the months of February, May and September in 1992 and 1993. The MAR fish assemblages were influenced
by the surronding substrate. Thus, a group of ubiquitous species, frequent on both substrata and typical of natural rocky
habitats (mostly Sparidae) and a group associated with the samples recorded on the Posidonia meadow (mostly Labridae) could
be distinguished. Season had only a secondary and slight effect on fish assemblages. The MAR was colonized by 74% of the species
in the first two years after deployment. Positive and lineal relationships between species richness, diversity, abundance
of necto-benthic species and time since deployment on sandy substrata were found. On Posidonia oceanica deployment time has
only increased very sedentary and cryptic species. Although some ways in which the MAR would have a productive function are
not rejected, the most obvious MAR working pattern is that of fish aggregation.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
16.
Xingwei Yuan Yazhou Jiang Hui Zhang Yan Jin Jianzhong Ling 《Zeitschrift fur angewandte Ichthyologie》2021,37(3):389-399
Artificial reefs are often deployed by many countries for the purpose of enhancing fishing after a period of several years. The objective of this study was to analyze the effect of a pilot artificial reef system deployment in enhancing the demersal fish assemblages, investigated using both acoustic methods and bottom trammel nets, during four years between 2011 and 2017, in Xiangshan Bay, Zhejiang Province, China. Comparisons of community indices, including fish biomass, species richness and species diversity, indicated relatively consistent trends between the control sites and the artificial reefs following their deployment in 2012. Fish density, represented by the value of the nautical area scattering coefficient, and fish biomass were significantly higher on the artificial reefs than at the control sites in 2015 and 2017, and species richness and diversity were significantly greater at the reefs from 2013 to 2017. Blackhead seabream (Acanthopagrus schlegelii) and false kelpfish (Sebastiscus marmoratus) were the dominant fishes on the artificial reefs, and the average body lengths of these two species were significantly greater 40 and 64 months after deployment. Thus, construction of the artificial reefs appears to have achieved their primary purpose as fish-attraction devices, thereby contributing to ecological restoration in Xiangshan Bay. 相似文献
17.
Prey selection behaviour of three-spined sticklebacks, Gasterosteus aculeatus L., was studied in two experiments. Where possible, the experimental apparatus satisfied the assumptions of the simplest optimal diet model (the basic prey model); prey were presented sequentially, the fish could not search for and handle prey at the same time, and net energy gain, handling time and encounter rate were fixed. Experiment 1 presented fish with a range of Asellus sizes so that pursuit ( p ) and handling ( h ) time could be related to prey size. Published energy values of Asellus together with pursuit and handling times were used to calculate E /( p+h ) for Asellus measuring 3,4,5,6,7 and 9 mm. Pursuit times did not differ with prey size but handling times did. E /( p+h ) was very variable particularly at the larger prey sizes. Experiment 2 presented fish with two sequences of prey differing in the encounter rate with the most profitable prey sizes. Fish did not select the diet predicted by the basic prey model tending to always ignore the largest prey even when net energy gain would have been maximized by including them in the diet. Further analysis showed that the probability of a prey size being taken was a function of prey size, fish stomach fullness and encounter rate. It is concluded that the basic prey model is too simple to capture the behaviour of the fish. One of its main faults is that the changing state of the fish through the feeding bout is ignored. 相似文献
18.
Spatiotemporal distribution of nocturnal coral reef fish juveniles in Moorea Island,French Polynesia
This study aimed to investigate the spatial structure of nocturnal fish communities at settlement on coral reefs in Moorea
Island lagoon, French Polynesia; and the temporal consistency of habitat selection between winter (April to June 2001) and
summer (November 2001). The Moorea lagoon was divided into 12 habitat zones (i.e., coral reef zones), which were distinct
in terms of depth, wave exposure, and substratum composition. Nocturnal visual censuses among the 12 habitats found that the
recently settled juveniles of 25 species recorded were dispatched among three communities spatially distributed according
to the distance from the reef crest (reef crest, barrier reef, and fringing reef communities). This spatial communities structure
of nocturnal juveniles was consistent in both winter and summer and would be explained primarily by a current gradient in
Moorea lagoon (current speed was high near the reef crest and decreased towards the beach) and by the topographic characteristics
of reef zones. Among the 25 species, 13 were recorded in both winter and summer. A comparison of the spatial distribution
between summer and winter for 13 species that occurred during both seasons found that only 4 differed between the two seasons.
For these species, habitat selection would be organized primarily by some stochastic processes such as inter- and intraspecific
competition, predation, and food availability. Overall, the present study allowed us to highlight that most nocturnal coral
reef fish juveniles at Moorea Island exhibited striking patterns in their distribution and current and topographic characteristics
of reef zones might exert considerable influence on the distribution of fishes. 相似文献
19.
Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden
The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11−29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3−8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger’s wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the reefs. A conclusion was done that environmental differences among the reefs and the habitats investigated were important components of abundance variations and species diversity of ornamental fish along latitudinal gradients in the Red Sea and the Gulf of Aden. 相似文献
20.
Regulated discharge produces substantial demographic changes on four typical fish species of a small salmonid stream 总被引:1,自引:0,他引:1
A hydroelectric power plant (HPP) started operation in December 2002 on the River Lhomme, (mean annual flow: 1.78 m3 s−1; mean annual water temperature: 9.9°C). The new HPP bypasses the river over a length of 1.2 km. The minimum flow allowed
in the bypassed section is currently fixed at 0.220 m3 s−1. Before the construction of the HPP, two contrasted 150-m-long reaches of the Lhomme were selected to estimate their total
fish population abundance and to analyse their fish population dynamics. Electrofishing was carried out in each of these two
reaches on 23 April 2002 in a natural flow situation to remove the fish. Other inventories were carried out in late April
or early May in 2003, 2004, 2005 and 2006 in minimum flow conditions. The results revealed a prompt and severe decrease in
the total fish biomass (up to 81% for grayling from 2002 to 2006) combined with severe changes in the fish community structure
that were not observed in a reference site. The effects of the flow reduction varied considerably depending on the size of
the individuals, the species concerned and their habitat availability, which was modelled using a classical physical habitat
simulation (EVHA method).
Guest editors: R. L. Welcomme & G. Marmulla
Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries 相似文献