scholarly journals Phytoplankton response to fish-induced environmental changes in a temperate shallow pond-type lake

2017 ◽  
Vol 25 (4) ◽  
pp. 211-262 ◽  
Author(s):  
Agnieszka Napiórkowska-Krzebietke
Keyword(s):  
Phytoplankton Biomass ◽  
Environmental Changes ◽  
Silver Carp ◽  
Ecological Status ◽  
Ctenopharyngodon Idella ◽  
Predatory Fish ◽  
Turbid Water ◽  
Clear Water ◽  
Water State ◽  
Pond Type

AbstractSince 1967, the temperate, shallow, pond-type Lake Warniak has been subjected to different biomanipulation methods including the introduction of common carp,Cyprinus carpioL., grass carp,Ctenopharyngodon idella(Val.), silver carp,Hypophthalmichthys molitrix(Val.), and bighead carp,Hypophthalmichthys nobilis(Richardson) and then their removal in an effort to control macrophytes and phytoplankton. Recently, pilot stocking with predatory fish, particularly pike,Esox luciusL., has also been conducted. Hence, an examination of the long-term response patterns of phytoplankton to multiple fish-induced stressors was undertaken. In recent years,Charadomination (2000-2004) has helped to stabilize a clear-water state, high/good ecological status, and meso-eutrophic conditions. After the disappearance of Charales in 2004, the rapid, unstable changes in phytoplankton biomass, structure, and biodiversity suggested a shift toward a turbid-water state. As a result, the phytoplankton assemblages changed from those dominated by cryptophytes Y+X2+X1+LO(2000-2004) through those dominated by cyanobacteria K (2005-2008), dinoflagellates LO+Y (2009-2011), and cryptophytes Y+LO+F+X2 (2012), to those dominated by diatoms D+K+P+A (2013-2014) with representative taxa that occur in nutrient-rich and/or nutrient-poor water bodies. The 1967-2014 changes indicated that four periods, two with clear-water state and two with turbid-water state, alternately, one after the other, resulted from different fish pressure. Higher autochthonous fish biomass was usually accompanied by lower phytoplankton biomass. In contrast, the introduction of Cyprinidae fish had a stimulating effect on summer phytoplankton dominated by cyanobateria. Among the nutrients, only phosphorus played an important role.

scholarly journals A Survey of Aquatic Invertebrate Communities in Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States

2013 ◽  
Vol 4 (1) ◽  
pp. 151-162 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
Emily S. Albin ◽  
Mark A. Kaemingk ◽  
David W. Willis
Keyword(s):  
Stable State ◽  
Aquatic Invertebrate ◽  
Turbid Water ◽  
Clear Water ◽  
Alternative Stable State ◽  
Invertebrate Communities ◽  
Physicochemical Variables ◽  
Water State ◽  
Invertebrate Abundance ◽  
Abundance And Diversity

Abstract Aquatic invertebrate communities are important to shallow lake ecosystem form and function, providing vital components to the food web and thereby important to achieving lake management goals. We characterized lake invertebrate communities and physicochemical variables in six Nebraska Sandhill lakes and examined these characteristics within an alternative stable state framework. Surveys were conducted during 2005 within each of these lakes by sampling aquatic macroinvertebrate abundance, zooplankton abundance and biomass, phytoplankton biomass, and physicochemical variables. When placed within an alternative stable state framework, the response variables exhibited a gradient of different ecosystem states. Two lakes appeared congruent with the clear water state (dense submergent vegetation, high invertebrate abundance and diversity, and low phytoplankton), two lakes were congruent with the turbid water state (high phytoplankton, low vegetation coverage, and low invertebrate abundance and diversity), and two lakes were intermediate, likely in a state of hysteresis (i.e., multiple states under equal environmental conditions). Principal component groupings further supported these findings by following similar lake-specific patterns with attributes of each stable state grouping meaningfully according to the observed lake states. The lakes contained varied fish communities, potentially influencing many measured metrics, through a top-down mechanism. Generally, lakes dominated by piscivorous fish displayed the clear water state, whereas lakes with abundant planktivores displayed the turbid water state. Shallow lakes containing dense invertebrate communities likely provide a rich food base to important fauna (migratory waterfowl) that aid in reaching desired management objectives for these systems. Multiple small lakes, in proximity, displaying divergent ecosystem states invites the opportunity for more in-depth analyses of driving mechanisms that will undoubtedly add to our ability to effectively manage these systems in the future.

Modern features of aquaculture of cyprinids in the republic of Iraq

2020 ◽  
pp. 6-14
Author(s):  
Farhan Yasin Hamed ◽  
Adelia Zakirovna Anokhina ◽  
Natalia Viktorovna Sudakova ◽  
Damelya Kazhigalievna Magzanova
Keyword(s):  
Silver Carp ◽  
Stocking Density ◽  
Fish Farming ◽  
Pond Water ◽  
Government Support ◽  
Bighead Carp ◽  
Ctenopharyngodon Idella ◽  
Natural Food ◽  
Hypophthalmichthys Molitrix ◽  
Fish Farms

It is shown that the leading role in the aquaculture of Iraq belongs to Cyprinids, which account for over 80 % of all fish farming production. The most widespread in the country are four main world species of carp aquaculture: common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis). Basically, the traditional technology of growing Cyprinids in ponds is used, which includes the main fish farming processes: care of broodstock to prepare them for spawning, collecting eggs and milt, eggs fertilization and incubation of embryos, raising juveniles and marketable fish. Currently, there are about 2 thousand private fish farms, which have ponds of various sizes from 4 to 100 hectares. Cultivation of Cyprinids in Iraq is carried out mainly by extensive methods: the use of the natural food base of reservoirs with low fish stocking density in polyculture. The fish productivity of ponds varies greatly in different fish farms from 1,5 to 6 t/ha, which is due to economic reasons. The data on changes in the temperature of pond water during the year and hydrochemical indicators are given, which shows favorable conditions for Cyprinids rearing. Information on the use of compound feeds for growing carp in ponds is provided, and data on the composition and nutritional value of the feed used. The fish culture indicators for the main biotechnical processes of the rearing of four Cyprinid species in Iraq are described in detail. In the conclusion, it is indicated that for the effective development of aquaculture in Iraq, government support is needed in the form of a developed long-term program and legislative acts.

Invasive Asian Carps in North America

2011 ◽  
Keyword(s):  
Great Lakes ◽  
Mississippi River ◽  
Silver Carp ◽  
Bighead Carp ◽  
Ctenopharyngodon Idella ◽  
Great Lakes Basin ◽  
Black Carp ◽  
Federal Department ◽  
In The Wild ◽  
Asian Carps

<em>Abstract</em>.—There are four species collectively known as the Asian carps: grass carp <em>Ctenopharyngodon idella</em>, bighead carp <em>Hypophthalmichthys nobilis</em>, silver carp <em>H. molitrix</em>, and black carp <em>Mylopharyngodon piceus</em>. These species have been introduced worldwide for aquaculture purposes. Subsequent to introduction into the southern United States, three species have become well-established in the wild (grass, bighead, and silver carps). Two of these species, bighead and silver carps, have been dispersing rapidly up the Mississippi River basin, wreaking ecological havoc along the way. As there are numerous connections between the Mississippi basin and Canadian watersheds, including the Great Lakes, there is considerable concern about their potential ecological impacts if introduced and established in Canada. In addition to natural dispersal, these species may also be introduced into the Canadian wild through the live food fish trade. In 2004, the Canadian federal department of Fisheries and Oceans Canada conducted a risk assessment to determine the ecological risk of Asian carps to Canada. This assessment included evaluating the risk of survival, reproduction and spread of these species, as well as their pathogens, parasites, or fellow travelers (e.g. other invasive species), should they be introduced into Canada. These components were assessed in an expert workshop using best available information on their biology, potential vectors of introduction, and impacts in both native and introduced ranges. The assessment concluded that the risk of impact was high in, at least, some parts of Canada, including the southern Great Lakes basin by all four Asian carp species.

scholarly journals Habitat selection by booming bitterns Botaurus stellaris in French Mediterranean reed-beds

Oryx ◽  
2005 ◽  
Vol 39 (3) ◽  
pp. 265-274 ◽  
Author(s):  
Brigitte Poulin ◽  
Gaëtan Lefebvre ◽  
Raphaël Mathevet
Keyword(s):  
Habitat Selection ◽  
Water Level ◽  
Environmental Changes ◽  
Open Water ◽  
Site Management ◽  
Clear Water ◽  
Percentage Cover ◽  
Multivariate Statistical ◽  
Reed Beds ◽  
Ecological Requirements

Data on habitat requirements of the threatened Eurasian bittern Botaurus stellaris are largely qualitative and limited to countries holding small populations. We assessed the habitat spectrum exploited by male bitterns during the breeding season, based on the analysis of 40 booming sites and 33 non-booming sites in 2,500 ha of heterogeneous reed-beds in the Camargue, France. Environmental variables contributing to booming site selection were, in decreasing order of importance, determined by their contribution to multivariate statistical models: water level in April, proportion of open water, density of dry and green reeds, percentage cover of non-reed species, salinity and turbidity of surface water, and reed height and diameter. Overall, booming sites were characterized by a homogeneous cover of relatively sparse green and dry reeds growing with other plant species in shallow (10–15 cm), clear water. Because these findings are contrary to the traditional perception of bittern habitat in Europe, a reassessment of the species' ecological requirements throughout its distributional range is warranted. In the Camargue the main factors involved in habitat selection (water level and dry reed density) are directly associated with site management, and bitterns respond rapidly to slight environmental changes.

scholarly journals Limnology of Lake Bogakain, Bandarban, Bangladesh

1970 ◽  
Vol 39 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Moniruzzaman Khondker ◽  
Md Almujaddade Alfasane ◽  
Md Shafiqul Islam ◽  
M Azmal Hossain Bhuiyan ◽  
Md Ataul Gani
Keyword(s):  
Water Temperature ◽  
Negative Correlation ◽  
Phytoplankton Biomass ◽  
Thermal Spring ◽  
Turbid Water ◽  
Depth Gradient ◽  
Chl A ◽  
Different Depths ◽  
First Time ◽  
Depth Water

Bogakain, a natural high altitude (372 m) lake of Bangladesh has been limnologically investigated for the first time. At mid-point, the depth of the lake was measured 46.54 m and the Secchi visibility was 2.37 m. Water temperature from 1-10 m depth gradient showed slight stratification in the lake which varied from 27.0 - 22.4° C at 1.00 pm. pH at the different depths ranged from 7.8 - 9.1, conductivity from 75 - 80 μS/cm and TDS from 39 - 42 mg/l. Alkalinity ranged from 0.8 - 1.24 meq/l and DO from 0.61 - 11.39 mg/l. A total of 40 species of phytoplank-ton were recorded from the lake of which 21 belonged to Chlorophyceae followed by Cynaophyceae (5), Bacillariophyceae (4), Cryptophyceae (4), Euglenophyceae (3), Dinophyceae (2) and Chrysophyceae (1). Bloom by Synnechocystis salina Wisl was observed at 10 m depth. Water temperature correlated negatively and significantly with depth. Phytoplankton biomass as chl a correlated positively with phytoplankton density and water depth. The former variable showed negative correlation with pH and water temperature. Lake Bogakain is the deepest natural lake of Bangladesh and many of the previous concepts regarding the lake i.e., fishless, highly turbid water and it has got a thermal spring at the bottom was found invalid. Key words: Bogakain; Limnology; Macrophyte; Phytoplankton; Bangladesh DOI: 10.3329/bjb.v39i2.7301 Bangladesh J. Bot. 39(2): 153-159, 2010 (December)  

Mate choice and visibility in the expression of a sexually dimorphic trait in a goodeid fish (Xenotoca variatus)

2004 ◽  
Vol 82 (12) ◽  
pp. 1917-1922 ◽  
Author(s):  
Alejandro Moyaho ◽  
Constantino Macías Garcia ◽  
Edgar Ávila-Luna
Keyword(s):  
Mate Choice ◽  
Geographical Variation ◽  
Female Mate Choice ◽  
Factorial Analysis ◽  
Sexually Dimorphic ◽  
Turbid Water ◽  
Population Differences ◽  
Clear Water ◽  
Water Turbidity ◽  
Female Mate

Male Xenotoca variatus (Bean, 1887) have shiny scales ("speckles") on their flanks, the number of which varies within and among populations. Using fish from two localities with turbid water and two with transparent water, we tested whether differences in the number of speckles were associated with differences either in water turbidity or with the expression of female mate choice. We also tested whether female mate choice was influenced by water turbidity. In our sample the number of speckles and water turbidity were not associated. A test including all the populations in a combined (factorial) analysis showed that in clear water females exhibit a preference for visiting the male with the largest number of speckles of a pair, though no population differences were detected. When tested in clear water, females spent more time close to a male with more speckles; in this instance, males were from a clear-water locality and possessed many speckles. Our findings suggest that female mate choice might not contribute to the geographical variation in speckle number, but may instead be constrained by the transmissibility of the signal.

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