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1.
The Diversity of Bacterial Communities Associated with Atlantic Cod <Emphasis Type="Italic">Gadus morhua</Emphasis> 总被引:1,自引:0,他引:1
The spatial and temporal changes in the bacterial communities associated with the Atlantic cod Gadus morhua were investigated using terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S recombinant DNA (rDNA).
Epidermal mucous was sampled from 366 cod caught in three harvest locations (Baltic, Icelandic, and North Seas) over three
seasons (spring 2002, autumn 2002, and spring 2003), and an automated method for the high-throughput processing of environmental
samples was developed using a Qiagen BioRobot. The analysis revealed that a diverse consortium of bacteria were found on fish;
γ-proteobacteria and Cytophaga–Flavobacter–Bacteroides (CFB) species were dominant. T-RFLP peak profiles suggested that operational taxonomic units (OTUs) related to Photobacterium sp., Psychrobacter sp., and Bacteroides sp. were common to all sites in all three seasons, but there were intersite variations in community composition. Cod caught
from different seas had distinct reproducible bacterial assemblages. Whereas communities from fish caught in the Baltic and
Icelandic Seas were relatively stable over the three seasons, those from fish from the North Sea changed significantly over
time. 相似文献
2.
Gustaf Almqvist Alma K. Strandmark Magnus Appelberg 《Environmental Biology of Fishes》2010,89(1):79-93
The Ponto-Caspian round goby (Neogobius melanostomus, Pallas 1814) most probably was established in the Gulf of Gdańsk, Baltic Sea, in the late 1980’s and has since become one
of the dominant species in the region. In this study we assess the role of round gobies as prey for two important fish species
in the Gulf of Gdańsk, cod (Gadus morhua) and perch (Perca fluviatilis). We compared their present diet with stomach analyses from the area prior the round goby establishment, as well as with
diet analysis from Baltic regions where round gobies are absent. There were large differences in the diet between cods from
the Gulf of Gdańsk 2003–2006 compared to cods in earlier studies (1977–1981) from the Southern Baltic Sea. There were also
large differences in cod and perch diets from areas with and without round goby. Presently, round goby constitutes the most
important prey for medium sized cods in Gulf of Gdańsk, and perch from the same area almost exclusively feed on gobiids. Stomach
analysis, trophic level estimates, and stable isotope analyses all indicated that cod and perch in Gulf of Gdańsk after the
round goby establishment belonged to a similar trophic level. Beside round goby, no mussel feeding fish contributed much to
the diet of cod or at all to the diet of perch. Thus, it is likely that round gobies constitute a new energetic pathway from
mussels to top predators. However, due to the short time elapsed after round goby establishment, we can only speculate on
the species future impacts on Baltic food webs. 相似文献
3.
Distribution of 0-group cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in August–September 2005 and 2006 was mainly restricted to the Atlantic waters of the western and central areas of the Barents
Sea. The main distribution of 0-group fish overlapped largely with areas of high biomass (>7 gm−2 dry weight) of zooplankton. The copepod Calanus finmarchicus and krill Thysanoessa inermis, which are dominant zooplankton species in both Atlantic and boreal waters of the Barents Sea, were the main prey of 0-group
cod and haddock. The main distribution, feeding areas and prey of 0-group cod and haddock overlapped, implying that competition
for food may occur between the two species. However, though their diet coincided to a certain degree, haddock seems to prefer
smaller and less mobile prey, such as Limacina and appendicularians. As 0-group fish increased in size, there seems to be a shift in diet, from small copepods and towards
larger prey such as krill and fish. Overall, a largely pelagic feeding behaviour of 0-group cod and haddock was evident from
this study. 相似文献
4.
Trends in interannual variation in maturation and spawning terms of various age cohorts in the Eastern Baltic cod population
in 1997–2009 were studied. Specific features in the age structure of the mature population part that were established by the
end of the first decade of the 21st century were clarified. The role of cod age cohorts in the current population reproduction
was considered taking into account the data on cod recruitment and fecundity. 相似文献
5.
G. M. Chuiko V. V. Zakonnov A. A. Morozov E. S. Brodskii A. A. Shelepchikov D. B. Feshin 《Inland Water Biology》2010,3(2):193-202
Persistent organic pollutants (POPs) were found in bottom sediments and muscles of a freshwater fish, bream (Abramis brama L.), from the Rybinsk Reservoir. The contents of POPs decreased in the following order: PCBs > DDT > HCH > HCB. The POPs
contents vary within the ranges of 0.14–50.8, 1.8–6.8, 0.64–2.6, and 0.06–0.41 \gmg/kg wet weight for fish and 24.8–425.6,
2.3–27.1, and 0.34–0.83 fug/kg dry weight for bottom sediments (except for HCH), respectively. The highest and lowest POPs
levels were found in the Sheksna and the Mologa reaches of the reservoir, respectively. The differences in the spatial distribution
of POPs in the reservoir relate to the ways that contaminants enter and migrate in the waterbody but not to various compositions
of bottom sediments. The waste waters of the city of Cherepovets are the main local source of POPs in the Sheksna reach of
the reservoir; in the Mologa reach, the contaminants enter with surface runoff and through global transboundary and local
atmospheric transports from the Cherepovets industry. The qualitative composition of POPs evidences their continuing income
to the reservoir. Considering the revealed levels of POPs accumulation and their legislative safe environment levels, it should
be concluded that PCBs represent the highest environmental threat to the reservoir’s ecosystem. 相似文献
6.
S. V. Aleksandrov N. N. Zhigalova A. S. Zezera 《Russian Journal of Marine Biology》2009,35(4):296-304
Long-term research in the Baltic Sea revealed the basic trends of zooplankton community variations depending on oceanographic
processes. Alternation of the periods of increase and decrease in salinity of the Baltic Sea against the background of climate
changes (temperature increase) and eutrophication affect the state of the entire Baltic ecosystem, including zooplankton.
For these periods, the dynamics of zooplankton in the Baltic Sea were analyzed based on literature data and results of regular
research in the southeastern Baltic Sea during 1998–2007. The changes in the hydrological situation were accompanied by significant
changes in the zooplankton community. In the 1990s–2000s, the abundance and biomass of brackish-water and thermophilous species
primarily of Cladocera and Copepoda increased markedly. The role of the previously dominant marine copepod Pseudocalanus elongatus decreased due to salinity reduction in the deep-water part of the Baltic Sea. Maximum development of zooplankton occurred
in years of the greatest warming-up of the water (2001, 2005–2007) against the background of a general positive trend of zooplankton
abundance in the last decade. 相似文献
7.
8.
The Salton Sea is a highly eutrophic, hypersaline terminal lake that receives inflows primarily from agricultural drainages
in the Imperial and Coachella valleys. Impending reductions in water inflow at Salton Sea may concentrate existing contaminants
which have been a concern for many years, and result in higher exposure to birds. Thus, waterbird eggs were collected and
analyzed in 2004 and compared with residue concentrations from earlier years; these data provide a base for future comparisons.
Eggs from four waterbird species (black-crowned night-heron [Nycticorax nycticorax], great egret [Ardea alba], black-necked stilt [Himantopus mexicanus], and American avocet [Recurvirostra Americana]) were collected. Eggs were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), metals, and trace elements,
with current results compared to those reported for eggs collected from the same species and others during 1985–1993. The
two contaminants of primary concern were p,p′-DDE (DDE) and selenium. DDE concentrations in night-heron and great egret eggs collected from the northwest corner of Salton
Sea (Whitewater River delta) decreased 91 and 95%, respectively, by 2004, with a concomitant increase in eggshell thickness
for both species. Decreases in bird egg DDE levels paralleled those in tissues of tilapia (Oreochromis mossambicus × O. urolepis), an important prey species for herons and egrets. Despite most nests of night-herons and great egrets failing in 2004 due
to predation, predicted reproductive effects based on DDE concentrations in eggs were low or negligible for these species.
The 2004 DDE findings were in dramatic contrast to those in the past decade, and included an 81% decrease in black-necked
stilt eggs, although concentrations were lower historically than those reported in night-herons and egrets. Selenium concentrations
in black-necked stilt eggs from the southeast corner of Salton Sea (Davis Road) were similar in 1993 and 2004, with 4.5–7.6%
of the clutches estimated to be selenium impaired during both time periods. Because of present selenium concentrations and
future reduced water inflow, the stilt population is of special concern. Between 1992 and 1993 and 2004 selenium in night-heron
and great egret eggs from the Whitewater River delta at the north end of the Sea decreased by 81 and 55%, respectively. None
of the night-heron or egret eggs collected in 2004 contained selenium concentrations above the lowest reported effect concentration
(6.0 μg/g dw). Reasons for selenium decreases in night-heron and egret eggs are unknown. Other contaminants evaluated in 2004
were all below known effect concentrations. However, in spite of generally low contaminant levels in 2004, the nesting populations
of night-herons and great egrets at Salton Sea were greatly reduced from earlier years and snowy egrets (Egretta thula) were not found nesting. Other factors that include predation, reduced water level, diminished roost and nest sites, increased
salinity, eutrophication, and reduced fish populations can certainly influence avian populations. Future monitoring, to validate
predicted responses by birds, other organisms, and contaminant loadings associated with reduced water inflows, together with
adaptive management should be the operational framework at the Salton Sea.
Guest editor: S. H. Hurlbert
The Salton Sea Centennial Symposium. Proceedings of a Symposium Celebrating a Century of Symbiosis Among Agriculture, Wildlife
and People, 1905–2005, held in San Diego, California, USA, March 2005 相似文献
9.
In the brackish Baltic Sea situated in the transition zone between the Atlantic and Euro-Asiatic continental climate systems,
the periods of high abundance of sprat of marine boreal origin coincide with a rich freshwater discharge, large water volume
inhabitable by fish, rather high winter temperature and low salinity limiting the stock of its main predator—cod (Gadus morhua
callarias). In the freshening periods an additional volume of water with acceptable oxygen and temperature conditions for
sprat is formed in the Eastern (E) and, especially, the Northwest (NW) regions of the Baltic Sea. This allows extraordinary
increase in sprat abundance/biomass. The conditions for sprat deteriorate during the period of active saline water inflows
and colder winters, especially in the NW region. Following the decrease in the volume of water acceptable for the wintering
of sprat as to temperature and/or oxygen concentration, some part of the stock may be forced to migrate southwards as in the
Southwest (SW) region the conditions are the most stable. This may cause an extensive mixing of the stock components of various
regions, hindering the differentiation of sprat regional units in the Baltic Sea. As no isolation of regional spawning concentrations
has been found, beginning with 1989 the Baltic sprat has been assessed and managed as one stock unit, despite spatial differences
in its morphological characters, growth rate etc. The alternation of periods of different regime-forming conditions (freshening
or oceanization) is probably triggered by climate changes. This regularity has been exploited for the composition of long-term
forecasts of qualitative changes in fish (incl. sprat) stocks in the Baltic Sea. 相似文献
10.
Investigations into the 0-group fish in the Barents Sea have been carried out since 1965, with the goal of estimating the
abundance of 0-group fish. 0-group abundance indices have been used in the assessment of the recruitment level and in recruitment
variability studies. However, the ecological importance of the 0-group fish in the Barents Sea has been less studied. Although
0-group capelin, herring, cod and haddock are widely distributed in the Barents Sea, the central area seems to be the most
important, accounting for approximately 50–80% of the annual biomass. The total biomass of the four most abundant 0-group
fish species can be up to 3.3 million tonnes, with an average of 1.3 million tonnes (1993–2009). Wide distribution and high
biomass of pelagically distributed 0-group fish make these fishes an important element in the energy transport between different
trophic levels and different geographical areas, having a critical impact on the entire Barents Sea ecosystem. In recent years,
capelin have shown a pronounced northward shift in biomass distribution, and several successive strong year classes occurred
during warm temperature conditions. Cod biomasses were unexpectedly low during warm years and were positively correlated with
spawning stock biomass, while the correlation with temperature was not significant. Haddock and herring show, as expected, increasing biomass with increased temperature when the spawning stock is at a sufficiently high level. 相似文献
11.
Over the past 20+ years, fish with elevated concentrations of mercury (Hg) have been observed in remote lake districts, including
the Adirondack region of New York. Across eastern North America studies have also reported a negative correlation between
fish Hg concentration and lake pH. Recent controls in emissions of sulfur dioxide (SO2) have resulted in some improvement in the acid–base status of acid-impacted surface waters including Adirondack lakes. In
addition, there has been an apparent decrease in atmospheric Hg deposition. A synoptic survey of 25 lakes in the Adirondacks
was conducted in 1992–1993 to analyze spatial patterns of Hg in the water column and yellow perch (Perca flavescens). The same cluster of 25 lakes was resurveyed in 2005–2006 to evaluate if changes in lake concentrations of Hg species or
fish Hg have occurred. We observed a varied response of changes in water chemistry and fish Hg concentrations. In twelve of
the resurveyed lakes the yellow perch had lower Hg concentrations, six lakes had yellow perch with higher Hg concentrations,
and in seven lakes yellow perch Hg concentrations did not change significantly (α = 0.05). Four variables appear to influence
the change in yellow perch Hg concentrations in the Adirondacks: watershed area, elevation, change in pH, and change in fish
body condition. We hypothesize that as the acidity in lakes is attenuated, the lakes may become more productive and/or water
quality conditions less stressful to fish leading to increasing fish body condition. As fish body condition improves, fish
exhibit “growth dilution” of tissue contaminants leading to lower fish Hg concentrations. 相似文献
12.
H. Möller 《Helgoland Marine Research》1984,37(1-4):389-413
As part of a survey on population dynamics and ecology of fishesin the Elbe River, seasonal and regional fluctuations of external fish diseases were studied from the open North Sea to Hamburg in 1981–1982. Clinical signs of 11 different diseases, several of them not being recorded before, were noted in 22 fish species. Averaged over all samples, the total disease prevalence was below 1 % in 16 species. Highest prevalences were found in smelt (12.7 %), eel (9.2 %), and flounder (5.5 %). The frequency of most diseases increased in larger (older) fish. High prevalences of skeletal abnormalities in cod could be related to abnormal migration habits of diseased fish. Spawning papillomatosis, skin ulceration, and fin rot in smelt occurred predominantly during the spawning season. Most diseases observed occurred at relatively high prevalences in the central Elbe estuary between Cuxhaven and Brunsbüttel. This is most obvious for lymphocystis, fin rot, skin ulceration, and bleaching syndrome in flounder, but such a tendency also seems to occur in cauliflower disease of eel, as well as spawning papillomatosis and pharyngeal granuloma in smelt. This area is less heavily polluted and less frequently affected by oxygen deficiency than the area upstream of Glückstadt, where diseases in general occurred at lower frequencies. Therefore, it is concluded that neither pollution nor lack of oxygen are the main triggers for the outbreak of diseases in Elbe fish. It is supposed that large tidal fluctuations of salinity are a major stress factor for fish in the estuary between Cuxhaven and Brunsbüttel. Flounder from this area usually are in a relatively bad nutritional state. Their condition factor increases significantly towards Hamburg, while their disease prevalence decreases in the same direction. 相似文献
13.
Model experiments on a possibility that pathogenic enterobacteria Salmonella enteritidis (Gartneri) can grow on decaying algal mats with prevalence of the filamentous algae Cladophora glomerata (L.) Kütz were carried out. Samples of algal mats have been collected in the eastern part of the Gulf of Finland in the Baltic
Sea. A bacterial culture of Salmonella enteritidis was placed into tubes containing samples of mats. The intensive growth of salmonella was noted in alga samples collected
in the freshwater zone (salinity 0.2–1.5‰); growth was practically absent in the samples of algae collected in a zone with
salinity 2–3‰, while salmonella remained viable in the control tubes with water without algae. The growth of coliform enterobacteria
initially inhabited in the algal mats was discovered in all experiments. Studies carried out in 2009 show that the thickness
of the algal mats in the costal zones of the Gulf of Finland reached 20 cm and their biomass reached a few tons per 1 km2. These experiments showed that dead algal mats stimulate the growth of enterobacteria in the littoral zone of the Baltic
Sea, especially in the freshwater part, and can promote the development of these pathogenic microorganisms. 相似文献
14.
First evidence of spawning of eastern Baltic cod (Gadus morhua callarias) in the Belt Sea,the main spawning area of western Baltic cod (Gadus morhua L.)
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A. N. Stroganov M. Bleil R. Oeberst A. V. Semenova H. Winkler 《Zeitschrift fur angewandte Ichthyologie》2018,34(3):527-534
Two cod stocks (western Baltic cod, WBC, and eastern Baltic cod, EBC) are managed in the Baltic Sea which is characterized by different main spawning areas and different main spawning periods. In this study we analyse the spatial and temporal occurrence of spawning individuals of both cod stocks in the main spawning grounds of the Baltic Sea based on eight microsatellite loci. Our results suggest that EBC (Gadus morhua callarias) has formed currently temporally stable, substantially homogeneous population not only in the Bornholm Sea (ICES SD: 25) but also in the Arkona Sea (ICES SD: 24). The presented analyses proved that EBC (G. m. callarias) can temporarily also spawn in the Belt Sea. 相似文献
15.
In the distributional overlap volume of Baltic cod Gadus morhua and its prey, studied in the Bornholm Basin in the southern Baltic Sea, only a fraction of the sprat Sprattus sprattus population vertically overlapped with the Baltic cod population. Sprat occurred in the intermediate water, in the halocline and in the bottom water, while herring Clupea harengus and Baltic cod occurred exclusively in the halocline and in the bottom water. Only parts of the sprat population were hence accessible for Baltic cod, and only a fraction of the sprat had access to the Baltic cod eggs below the halocline. Baltic cod–clupeid overlap volumes appeared to be determined by salinity stratification and oxygenation of the bottom water. Hydrography time series were used to estimate average habitat volumes and overlap from July to September in 1958–1999. In the 1999 survey spawning Baltic cod had greater ratios of empty stomachs and lower average rations than non-spawning Baltic cod. The average ration for Baltic cod caught within 11· 4 m from the bottom (demersal) did not differ from the average ration of Baltic cod caught in shallower waters (pelagic), because spawning and non-spawning Baltic cod in both strata were caught at equal rates. The diet of the Baltic cod caught demersally contained more benthic invertebrates, especially Saduria entomon, but Baltic cod caught pelagically also had fresh benthic food in their stomachs, indicating vertical migration of individual fish. 相似文献
16.
Matthias Schaber Holger Haslob Bastian Huwer Anne Harjes Hans-Harald Hinrichsen Marie Storr-Paulsen Jörn O. Schmidt Rüdiger Voss Viola Neumann Friedrich W. Köster 《Biological invasions》2011,13(12):2647-2660
In 2007 the alien invasive ctenophore Mnemiopsis leidyi A. Agassiz 1865 was recorded for the first time in the Bornholm Basin, an area which serves as important spawning ground
for Baltic fish stocks. Since M. leidyi is capable of preying upon early life stages of fish and further might act as food competitor for fish larvae, it is of major
concern to investigate the potential threat that this non-indigenous species poses to the pelagic ecosystem of the Baltic
Sea. The present study investigates the temporal and spatial overlap of M. leidyi with eggs and larvae of Baltic cod (Gadus morhua L.) and sprat (Sprattus sprattus L.) in order to assess the potential impact of this new invader on two of the most important Baltic fish stocks. Results
show variable inter-seasonal distribution and overlap dynamics and thus different seasonal threat-scenarios for the early
life stages of cod and sprat. The spatial overlap between M. leidyi and ichthyoplankton was low for most of the period observed, and we conclude that M. leidyi presently does not have a strong impact. However, we detected situations with high overlaps, e.g. for sprat larvae and cod
eggs in spring. As the population dynamics of M. leidyi in the central Baltic are not yet fully understood, a future population explosion of the alien ctenophore with possible effects
on fish recruitment cannot be ruled out. Furthermore, a possible shift in peak spawning of cod to the early season, when ctenophore
abundances were relatively high, might increase the impact of M. leidyi on cod. 相似文献
17.
The rapid spread of Mnemiopsis leidyi across the entire Baltic Sea after its first observation in 2006 gave rise to the question of its invasion pathway and the
possible vector of its transport. To investigate pathways of M. leidyi invasion, the years 2005–2008 have been simulated by a three-dimensional coupled sea ice-ocean model of the Baltic Sea. In
addition, a Lagrangian particle-tracking model has been utilized to test possible transport routes of this invader for 2006/2007.
Based on the model, we exclude advection from the Kattegat as the main area of origin of M. leidyi and further spreading through the entire Baltic Sea. To explain the dispersion of M. leidyi in 2007 an earlier invasion already in 2005 is most probable. Alternatively, an invasion originating from main harbors with
high ship traffic could also be a potential pathway. Drift simulations with drifter release in the main harbors are in good
agreement with the observed distribution pattern of M. leidyi. 相似文献
18.
We investigated the seasonal maturity development of cod in four areas of the Baltic Sea. Two different spawning peaks were identified and found to be consistent over the period 1992–2005. In the Kiel Bight and Mecklenburg Bight (ICES SD 22) a spawning peak was observed from March to April (spring spawning). In the areas of the Arkona Sea (ICES SD 24) and Bornholm Sea (ICES SD 25) the spawning peak occurred during summer. In the Bornholm Sea, the main spawning activities began in June and ended in September, with a spawning peak in June–August (summer spawning). In the Arkona Sea, which is a transition area between the Mecklenburg Bight and the central Baltic Sea, spawning began in March and lasted until July, with a spawning peak in June–July (summer spawning). Seasonal maturity development and proportions of spawning cod in June in the Arkona Sea were similar to that of the Bornholm Sea. In addition, the proportion of spawning cod in the Arkona Sea was positively correlated with the size of the spawning stock in the Bornholm Sea. Our results provide evidence of a spatial expansion of spawning activities of the summer spawning stock from the eastern Baltic Sea into the Arkona Sea. Therefore, the Arkona Sea should be considered as one of the spawning habitats of the summer spawning stock of Baltic cod. 相似文献
19.
The seasonal dynamics of phyto- and zooplankton, as well as their trophic interactions, were studied for the shallow freshwater
hypereutrophic Curonian Lagoon in the Baltic Sea in 2007–2009. The water temperature and high concentrations of nutrients
were the limiting factors in the seasonal dynamics of the studied communities. Decreases in the B
z
/B
ph
ratio and the grazing pressure of phytophagous zooplankton were observed over the last few decades due to the eutrophication
process and cyanobacteria blooms. The large zooplankton consumes a significant amount of primary production (Chlorococcales
and Bacillariophyta) when the predator pressure of the fish fry is absent. This grazing pressure may precondition cyanobacteria
scum. 相似文献
20.
During a North Sea survey in late spring 1986, zooplankton biomass (g dry weight/m2) as well as pollutant concentrations in zooplankton (ng/g dry weight) were determined at 127 stations. On the basis of these
data, the load of several cyclic organochlorines in zooplankton (ng/m2) was estimated. It appeared that the highest loads of these pollutants were incorporated in the large zooplankton stocks
of the northern and central North Sea, north of 56°N, whereas the highest concentrations were found in zooplankton of the
southern North Sea. An explanation for the accumulation of pollutants in sediments as well as in benthos organisms of the
central and northern North Sea as found by several authors is discussed in connection with the assumption of a considerably
high vertical flux of organic material in these areas. The calculation of total zooplankton content in the North Sea during
the late spring survey amounted to about 5 million tons dry weight. This biomass was estimated to contain about 2.6 t PCBs,
19.3 kg p,p′-DDE, 12 kg τ-HCH, 6.4 kg HCB und 5.6 kg α-HCH. These results agree with those on other compartments of the North
Sea ecosystem (benthos, fish) found in recent literature. The estimated annual turnover of PCBs in zooplankton (15.2 t) is
of the same order of magnitude as the estimated amount transported yearly into the North Sea by rivers and the atmosphere
(6–13 t). 相似文献