Aquatic Ecosystems

Aquatic Ecosystems

  • Cui Xu added an answer:
    Why is it important to quantify the stoichiometry of species in aquatic ecosystems?

    In aquatic ecosystem, nutrient limitation has a long research history. I am wondering the reason why it is important to quantify the stoichiometry of a specie or species. Would anyone help me to understand this topic?

    Cui Xu

    Yes, I am referring to elemental stoichiometry.  I have read the book "Ecological Stoichiometry" by Sterner and Elser. In this book, they did describe what is ecological stoichiometry and why they focus on it. I think It's interesting to know deeper about the differences of ecological stoichiometry among different autotrophic or heterotrophic species.

    However, I can't understand the meaning of this differences. Are the differences demanstrate competitive ability of species? or other meanings?

  • Gustavo Enrique Chiaramonte added an answer:
    Can anybody help me with a nomenclatural problem?

    I am facing a nomenclatural problem and I need help. During my masters, I did a taxonomic review of two freshwater stingrays, P. orbignyi and P. dumerilii. As a conclusion of my work I proposed that they were synonyms. However, I did not know which name had precedence over the other since both were originally described in the same work by Catelnau in 1855. Consulting the ICZN (article 24) they proposed that this nomenclatural act should be resolved by the principle of the “First Reviser”. Carvalho et al. (2003) (in a checklist) proposed P. orbignyi as a senior synonym of P. dumerilii (acting as the “first reviser”) and as a consequence I gave precedence to the name P. orbignyi and included P. dumerilii as a junior synonym. However, P. dumerilii was described in a previous page (p. 101) to P. orbignyi (p. 102). In this case, does the P. dumerilii have precedence over the P. orbignyi since it was described in a page previous to it (nullifying the decision of the “First Reviser”), or should I accept the decision of the “first reviser”? None of the names has fallen in disuse and both have been used in the present literature, with some researchers still considering P. dumerilii as a valid species. How to proceed in this case?

    Gustavo Enrique Chiaramonte

    Dear João, I understand you perfectly, and hope you can publish the results of your master successfully. I'll be waiting for them. Meanwhile, I'll take your opinion into account in any future work that may involve this / these species. Thank you very much. Regards


  • Andre Barreto added an answer:
    Does anyone know of a disease/condition that affects bottlenose dolphins (tursips sp) where a "fleshy, seaweed-type growth" protrudes from the mouth?

    I have run across a number of anecdotes of this growth affecting some Tursiops aduncus bottlenose in/around the Broadwater estuary on the Gold Coast, Australia, around 10-15 years ago (2000-2005). No-one has been able to provide me with pictures. The growth protruding from their mouth made it impossible to accept food from boaters who tried to provision them. Not surprisingly, they disappeared fairly quickly.

    I've found one passing reference to a similar condition but the study simply made mention of a male, on its own, with the growth, and didn't study or investigate further.

    I'd be interested of any other sightings of such a condition, any thoughts on what it might be, or any photos.

    Andre Barreto

    Since you don't have photos, it's difficult to know what the cause of the condition you mention. However, the video and photo from Simon seems to me to be stalked barnacles. They have been described in many cetaceans, and I've found in franciscanas (Pontoporia blainvillei) from my area. You can see a photo of it at

  • P.J. Mudie added an answer:
    What age correction is needed for mollusc C-14 dates from Black and Marmara Sea lacustrine phases?

    High resolution dating of events in the Black and Marmara Seas during non-marine phases requires appropriate correction of C-14 ages because shells are not in equilibrium with global values of ca. 400 yr. Proposed values range from 0 (fully mixed, in equilibrium with atmosphere, no correction needed) to 1000 yrs (benthos contain old bottom water or river transported carbon). Peat (grows in equilbrium with atmosphere) compared to in-situ shell from the same sample   indicates a reservoir correction of ca. 850 yrs is needed for shells. Which correction value is correct for A) Black Sea? B) Marmara Sea with overflow water.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Dating of major sea-level changes using shells or calcareous microfossils is prone to errors in semi-enclosed marine environments where inputs of seawater and river water vary over time and space. The need to refine mollusc-based age estimates for the rate of the Holocene marine transgression in the Black Sea is the focus of multiple palaeoceanographic and archaeological studies. This ongoing “dating game” seeks to clarify conflicting evidence for a hypothetical catastrophic marine flood that forced the emigration of Neolithic farmers from the shores of a Holocene freshwater lake in the Black Sea. The potential importance of confirming or rejecting this megaflood hypothesis has led to multiple attempts at refining the chronology of the marine transgression and quantifying the palaeosalinity of the Black Sea surface water during the Holocene. Here we report that six new AMS radiocarbon ages of 8890 ± 50 to 8450 ± 40 yr BP were obtained for wood, grass and sedge leaves from peat layers in Core 342 at 33.16 - 32.71 m below present sea level on the Ukrainian Shelf. These plant materials provide critical new ages for quantifying Black Sea carbon reservoir issues. The accuracy of our new AMS wood/peat ages is independently supported by palynochronological correlation. The ages of our plant materials have ~100 years precision and are ~420 - 520 years younger than those previously reported for unsorted detrital peat in Core 342. Paired mollusc—wood ages for brackish—freshwater Dreissena polymorpha shell from detrital peat also shows that an inaccuracy of >1120 yr can arise for shells during times when carbon reservoir values in the semi-isolated, brackish-water Black Sea could depart significantly from global average. Our revised sea level curve shows a gradual early Holocene transgression from water depths of −45.9 to −32.8 m, with initial Mediterranean inflow by 8.9 ka BP.
      Open Journal of Marine Science 01/2014; 4(1):1-7. DOI:10.4236/ojms.2014.41001
    P.J. Mudie

    Thanks for all your answers. In Marmara Sea we have new cores with lacustrine sediment containing shells next to tephra layers dated by wood. These may provide a more accurate reservoir correction value for the late Pleistocene interval.

  • Raymond K. Timm added an answer:
    What relationship exergy and primary production and destruction?

    I explore generalized parameters of aquatic ecosystems to assess the evolution of their state under anthropogenic effect. What parameters are preferable?

    Raymond K. Timm

    Mikhail - I love your research question! Of course no model is adequate to describe all the interactions in constantly perturbed environments.  If you could stack integrals from 0 to infinity you could model ecosystem behavior. Every independent variable is also dependent on every other.  For example, high stream discharge can be disastrous for incubating embryos of lithophillic spawning fish.  But, high discharges provide hydrologic connectivity for rearing juveniles.  And of course, not every place is equally productive or safe.  So, you have to incorporate space and time and life history stage(s).  One statistical approach I have used is classification and regression trees.  They can overfit relationships.  But, who cares.  In ecosystem studies, really what you want to know is the hierarchy of importance between dependent and independent variables.  I've attached 2 papers that illustrate my thinking.  The first quantifies the spatial and temporal nature of a physical disturbance in a river.  The second shows how fish responded to that disturbance when placed in the context of the whole river.

    I hope these are helpful for you.  Please feel free to email me directly if you have any questions.

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  • Xiaowei Jin added an answer:
    Does anyone have any papers about the development of low-cost ecotoxicological test with aquatic invertebrates?

    I'm reviewing information on the issue of low-cost methods in ecotoxicology, and I have some studies on it, such us Mills CL et al. 2006 Development of a new low cost high sensitivity system for behavioural ecotoxicity testing Aquatic Toxicology 77: 197-201 I would like to know other studies on it.

    many thanks


    Xiaowei Jin

    A Simple Low-Cost Field Mesocosm for Ecotoxicological Studies on Earthworms. 

    PHYSIOL C PHARMACOL TOXICOL ENDOCRINOL , vol. 117, no. 1, pp. 31-40, 1997
    DOI: 10.1016/S0742-8413(97)85596-X

    GamTox: A Low-Cost Multimetric Ecotoxicity Test with Gammarus spp. for in and ex situ Application

    International Journal of Zoology
    Volume 2011 (2011), Article ID 574536, 7 pages

  • Najat Alomari added an answer:
    Can anyone identify this sea slug?

    can anyone please do identify this sea slug(is it really a sea slug??) i got this from chennai beach. it weighs arroung 127g. has a scaly appearance like a snake. and these scales are brown colour with brown dot in the middle of the scale. near to the mouth it has more than 10 tentacles.
    thank you for identifing it.

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    Najat Alomari

    This is sea cucumber  belongs to the family Holothuriidae it seems to be holothurian??

  • João Paulo Medeiros added an answer:
    Has anyone amplified COI successfully from freshwater oligochaetes?

    I already tried universal primers (Folmer et al., 1994) and others like COI-E and AnnCOIF used in published papers, with different temperature programs but without results. Does anyone has a PCR protocol that already used and worked sucessfully for these annelids?

    João Paulo Medeiros

    Thank you for your answers... I will try both Svante and Jonathan protocols and see the results :-)

  • Muthuswamy Jaikumar added an answer:
    Is there data other than USEPA literature values LC50 for Selenium for marine species ?

    I have searched literature values for Selenium (Sodium selenate). I got USEPA literature 2004. I need other than USEPA: Australian, ASEAN and New Zealand water quality criteria for selenium lc50.

    Muthuswamy Jaikumar

    Dear Arif thank you for sending a link in that i seen same USEPA data. Like USEPA i need literature values neither like Australian, ASEAN and New Zealand water quality criteria for selenium lc50 for marine water species. 

    Thank you for sharing this information 

  • Ted Swift added an answer:
    What are potential research implications of landscape community genomics on stream/river ecology and riparian ecology?

    Landscape commuity genomics is related to eco-evolutionary processes in complex environments, such as stream and riparian ecosystems. However, its framework is not clear at the moment, because we don't know how genomic variation is affected by dynamic interactions between abiotic (environmental) and biotic (community) effects..

    Ted Swift

    Thanks to Francis for linking in Hand et al.'s essay. Very interesting, and one of those concepts that's obvious...after it's pointed out. As Edward Tufte reminds us "It's More Complicated Than That!". The research implications? As usual, it's a case of a big idea that needs to be translated into testable hypotheses on scales that can be studied on practical levels. In riparian corridors, you might expect -for example- genetic variation to be more highly correlated along the corridor, where conditions are similar, than across a stream-to-upland gradient. Or maybe the opposite, depending on the organism.

  • Francisco Lakay added an answer:
    What are good standard methods for calculating MPNs from sediments?

    I am looking to run survival experiment  of bacteria in a lake mesocosm and would like to count viable cell numbers over time in sediments. Ideally, I would like to be able to calculate CFU/ml and not CFU/g so I can compare to growth in lake water as well. I have tried Beat Beating with 2mm beads but my recovery is very low. Any suggestions or ways people get around the mass to volume comparisons!? 

    Francisco Lakay

    Hi, if you are only looking at bacteria, you can use differential centrifugation. You first spin down at 2500 rpm to pellet all the larger cells and debris, with the bacteria still in solution. After decanting the solution to a new container, spin down at 10 000 rpm to pellet any bacteria in solution.

    Although this is a very basic method, it allows you to study bacteria in any environment, minus some of the background noise. You can also combine diff. centrif. with bead beating - that way you know that most of your extracted DNA will be from bacteria.

    I would also suggest using DAPI to stain only viable cells.



  • Domenico Voltolina added an answer:
    What's the name of this microorganism identified by microscope?

    The short chain chain alkanes C15,C16 and C17, likely derived from algae, bacteria, dominate the n-alkane composition in lake sediment. Now, We have already identified  some microbials (the round object in the attached picture) with microscope in lake sediemnts at Zigetang Co on Tibetan Plateau, but we are not sure what's they are. Someone guess this is the head of Copepods (Zooplankton) Would you please tell us if you know? Thanks a lot.

    Domenico Voltolina

    on an afterthought, Kamal and Lofti are right. Not a cyanobacteria, but I would go for a green. To me, the area around the central part might indicate a cyst, I agree with Roman's suggestion: examine fresh samples and if possible isolate these cells. Cysts resist harsh treatment, so treat your samples with peroxide or with acid and see what happens. you might get lucky and get living, swimming cells.. Here goes something you might find of interest. good luck

  • Jorge Ramirez added an answer:
    What is a good modeling program for trace contaminants in large river systems?

    I am studying the concentrations of sucralose, an artificial sweetener, in the Ohio River. There will be 25 sampling sites between Pittsburgh (PA) and the Mississippi River confluence.

    Jorge Ramirez

    Hi Ben,

    If you use CAESAR, keep in mind that the tracer component only tracks contaminant that binds to sediment.


  • Hartmut Nies added an answer:
    Does anyone have any links on the further degradation of microplastics in the marine environment?

    I'm currently working on an assignment on the degradation of microplastics in the marine environment, I have found a good breadth of background knowledge and literature on the degradation of plastic debris to microplastics but i'm having trouble finding literature on the further degradation microplastics to nanoplastics and thir impacts etc. Any help would be greatly appreciated!

    Hartmut Nies

    Recently, GESAMP published a report about Micro-plastics in the ocean. You can download the report with an assessment here:

  • Phillip Haubrock added an answer:
    Does anyone know an expert of european and asian newts?

    While collecting insects I found two small newts in a pond near Kassel, Germany.
    The species looks a lot like Cynops, but I would like to know if someone is able to identify it more properly.
    Please send me an e-mail adress and I will send pictures as soon as possible, since I am currently unable to upload any pictures.

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    Phillip Haubrock

    At first, we thought it might be C ensicauda or C. pyrrhogaster, but was later then classified as Cynops pyrrhogaster. We suppose, that it is unlikely that C. pyrrhogaster can survive a long time (couploe of years) in this climate, but we do not outrule it yet.
    Therefore I will keep monitoring this pond, but so far, I was unable to find any other newt species. Sadly I do not know if there were any other newts in this specific pond, so it is hard to make any suggestions.

  • NPP Liyanage added an answer:
    Can aquaculture water quality be tested on its own without relating to reared specimens?

    I've encountered several journal articles and studies that show aquaculture water quality is not usually studied on its own and the studies show results are tied to specimen immune response. 

    NPP Liyanage

    I believe you can get a clear answer if you can elaborate the question little bit.

    Anyway, any kind of aquaculture totally depend on the water quality (WQ). therefore it is essential to monitor the WQ. Frequency of monitoring is depend on the intensity of aquaculture. Intensive culture required more accurate frequent monitoring while extensive cultures neglect WQ monitoring.

    However, since ambient WQ affect on growth and health of culture spp in many ways it is essential to monitor WQ. Bad WQ will stress fish by creating unfavorable environmental conditions. So due to this stress, there immune system might get weekend and may cause diseases.

  • Florian Koch added an answer:
    Are you aware of studies on naturally (acidic) vs. anthropogenically (acidified) low pH estuaries?

    The question revolves around the concept of acidification of estuaries, as an ecological process which may be induced by human activities. In tropical conditions, high rainfall, heat and high primary production and specific geological settings may determine soil acidic conditions, which may control relatively low pH conditions in estuaries (i.e., in the lower tract of hydrogeographic basins). I am looking for the available literature and an overview/discussion on the state of art of this topic.

    Florian Koch


    IN my old lab they are spending a lot of time with exactly these kind of questions.  I would look at the Christopher Gobler’s Laboratory page at Stony Brook University and his recent publications.  Also his PhD student Ryan Wallace has done a lot of work in Jamaica Bay, Long Island Sound and many of the Islands numerous barrier island estuaries with regards to pCO2, alkalinity and DIC measurements in addition to numerous other environmental parameters.  Check out their lab page and publications and maybe shoot them an email.

    Cheers and good luck.

  • John J. Hains added an answer:
    Does anyone know of techniques of publications for gap filling dissolved oxygen data in freshwater habitats?

    We are currently using D-Opto dissolved oxygen sensors in marsh habitats to measure continuous seasonal changes in dissolved oxygen.  Power issues and occasional sensor issues leads to gaps in our data set, which we would like to fill in order to conduct the appropriate time series analysis.  Unfortunately, literature searches have yielded little information regarding methods for gap filling dissolved oxygen data.  For this reason I am reaching out to the Research Gate community for advice.  Thanks :)  

    John J. Hains

    What is the frequency of measurement during normal operation? How long are the gaps? You need to provide a little detail. 

  • Sandipan Gupta added an answer:
    Is Mystus gulio (locally known as Nuna Tengra) a threatened native estuarine catfish?

    Yes. According to IUCN (2000) Mystus gulio (locally known as Nuna Tengra) a threatened native estuarine estuarine catfish, enjoys a high consumer preference fish in many Asian countries including Bangladesh.

    Sandipan Gupta

    The ratio with which Mystus gulio was stocked is not clear from this paragraph. To analyze this I think few factors to be considered, i) the feeding niche of the fish species poly cultured, ii) stocking density. As per the information provided in T2 and T3 Mystus gulio was cultured with O. niloticus and R. corsula (with varying stocking density); so how can it be concluded or rather to be compared; for this you will have to culture Mystus gulio with O. niloticus (in one experiment) and with R. corsula (in another experiment). Then one can compare the growth difference.

  • Geraldina Signa added an answer:
    Can anyone identify this tropical large goby?

    This specimens was catched in a channel passing through a mangrove forest in Kenya and is quite large (Standard lenght 17 cm). 

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    Geraldina Signa

    thanks a lot to both of you!

  • Gustavo Henrique Pereira Dutra added an answer:
    What are the major causes of fish mortality in net cages?

    Would you any body provide me possible answer? Thank you.

    Gustavo Henrique Pereira Dutra

    Dear Mohammad, the main cause of death in marine aquarium is parasitic (Oodinium and Cryptocarion irritans, as dinoflagelates and protozoa, respectively; and monogenea trematoda). Brazilian Hugs

  • Jorge Tornero added an answer:
    What types of weights do you use on board research vessels at the sea?
    I need some information on weights for marine investigations. Can you inform me - what types of weights do you use aboard research vessels at the sea? Are there any weights with resolution 0.1 g or higher? We used Pols with such resolution long time at PINRO, but now Pols is not exist. I will grateful if you can provide model name and producer (and site where it will be possible to see it).
    Jorge Tornero

    Here in our lab at Cadiz we own one Pols scale with 0.01/0.02 g resolution, up to 0.130 kg.

    This scale, under our usual sea conditions and ships performs reasonably well and we use it mainly to weigh anchovies and sardines and their gonads as well as many other species when appropiated. 0.1 g resolution is also used, mainly for mackerel, horse mackerel and friends up to 1.3 Kg I seem to remember (with triple resolution range, 0.1, 0.2 and 0.5 g)

    Unfortunately Pols not longer exists (was, among others, phagocited by Marel) and it looks like Marel is not much interested in producing "high resolution", scientific grade scales. They are stuck to 3000 scale divisions so the highest resolution you can get from them is, as P. kainge has pointed out before is 0.1 g up to 0.3 kg.

    And yes, they don't list the 0.1 g scale in the web but it exists for sure. We are on purchasing two marine scales for the lab this year and this ws one of the candidates. By the way, the actual name of the model is M2200 with platform PL2220, 0.1 g 0-300 g

    Best regards

  • Nadezhda Ivanovna Yermolaeva added an answer:
    Does anyone have any experience in creating thermal refugia patches in standing water?

    I would like to investigate the use of thermal refugia by non-native crayfish species in the UK, by setting up tanks with a "patch" of water which is a constant temperature, whilst the rest of the tank varies naturally. Basically trying to mimick a groundwater upwelling, but on a small scale.  

    Preferably, the thermal refuge area would not be enclosed and used as a natural shelter by the crayfish. 

    Any ideas of ways to design this type of tank would be greatly appreciated!

    Nadezhda Ivanovna Yermolaeva

    If you want a well-defined temperature in the refuge - you need a thermostat for the aquarium.
    If you just need to raise the temperature (relative to the rest of the tank), it is possible to tighten the part of the surface water by the black film. To reduce the mixing under the film can to be create artificial macrophytes - on a clothesline to hang strips of polyethylene film.

  • B. Manikandan added an answer:
    Which statistical methods can be applied for analysis of time-series data on percent cover of benthic forms in a coral reef ecosystem?

    I had collected data on the percent cover of benthic forms including corals, macroalgae etc. continuously for 2 years in 2 different study sites. Analysis of the results revealed short term proliferation of macroalgae in the study sites with corresponding decrease in the percent cover of other benthic components. Kindly advise me what statistical methods can be applied to suitable interpret the results.

    B. Manikandan

    Jose @ Thank you for the reference. I will look in to it.

  • Jack Edward Lee added an answer:
    How much Ammonia (NH4) is deposited into freshwater from the atmosphere?

    I know this is question highly depended on geographic location, but is there an average deposition of NH4 from the atmosphere into a body of freshwater? I'm specifically looking for a reference that gives the amount of NH4 deposited into a litre (or m2- surface area) of water per year. I'm looking for references ideally from the UK. 

    I'm specifically looking for references that report atmospheric deposition, independent of dust/rain/bird droppings etc. 

    Any help or advice pointing me in the right direction will be very much appreciated.

    Jack Edward Lee

    @Chandravadan Trivedi 

    Atmospheric NH3 deposition is a really big problem.

  • Geoffrey Marchal added an answer:
    Does anybody have any methods/ tips/ helpful advice for remediating a coastal sand dune?

    This is for a final year project so I can't do anything too big. I'm looking at replanting vs seeds with and without alginate gels so far. The area is not huge ~570m2, but the aim is basically to get an idea if a method looks like it will provide faster regeneration.

    I know not a lot has been done in this area so any helpful ideas would be appreciated.


    Geoffrey Marchal

    I´m not an expert on that. But I guess you will have more chance by replanting bushes with fast growth like Atriplex halimus. It is a fast growing halophyte bush.

  • Caterina Milillo added an answer:
    Is there anyone who is working on eDNA for aquatic plants in a freshwater ecosystem?

    How can we identify the species from the DNA cocktail we are getting as eDNA from water?

    Caterina Milillo

    I have never worked with e-DNA, but it is a subject that interests me. Try to look at this link. It is a review on its applications:

  • John R. Helms added an answer:
    What's the source of short chain alkanes?

    Zigetang Co is a meromictic endorheic saline lake without any glaciers in the catchment on Tibetan Plateau, which is directly located at the boundary of the Indian monsoon. The short chain n-alkanes C15, C16 and C17, likely derived from aquatic algae, plankton and photosynthetic bacteria, dominated most of the lake sediments. Howerver, we are not sure how to explain the source of these short chain alkanes. Do you have some ideas or some similiar papers discussing the short chain alkanes? Thanks a lot.

    John R. Helms

    In addition to some of the earlier advice, there is an extensive literature dealing with sources of alkanes and other lipids for use as sedimentary and geological biomarkers. It might be worth querying your data using the "terrestrial aquatic ratio (TAR)" biomarker index and the "carbon preference index (CPI)" and compare with previously published values to determine source, diagenetic state, as well as possible anthropogenic contamination.

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  • Richard Chadd added an answer:
    Which caddisfly species are characteristic of English winterbournes?

    There is a current debate over how to properly characterise winterbournes on chalk geologies in ecological terms. There are some key species already well documented (e.g.the mayfly Paraleptophlebia werneri Ulmer), but I'm not so sure of the key caddis species. Does anybody have any ideas? Notionally, it will allow us to distinguish ephemerality caused by abstraction pressures against naturally ephemeral streams.

    Richard Chadd

    Hi Terry,

    I had a look at Andy's publication in British Wildlife (October 2009) as directed by Paul. Some of the key species were Limnephilus vittatus, L. bipunctatus & L. centralis.



  • M. Selvanayagam added an answer:
    What is this caddisfly (Trichoptera) form? And is it really an indicator of freshwater quality?

    I found this larvas near side of freswater located at North of Turkey (East of Blacksea Region) in spring 2014. So there are many of family and form of caddisfly. Is it possible to determine family and form of its? And very few study indicate that there is a relationship between water quality and its living condition and "most types of caddisflies are pollution sensitive. Caddisflies are a good indicator of water quality because they live within a diversity of habitats. However, some types that are widespread, can tolerate pollution and environmental stress".

    Even if this species one of the indicators of water quality, I can't guess whether freshwater have good quality or not because some of forms can tolerate pollution and environmental stesses.

    Have you any idea about this issue?

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    M. Selvanayagam

    yes Ttrichopteran are good indicators of  water quality and that why they are included in EPT for water quality assessment. There are  different species, some of them  case makers while others non case makers .The larval forms  could be identified based on the   presence of three  dorsal plates with out hump family-Hydropsychidae, with two dorsal plates with out any hump as in  family Brachycentridae,,with dorsal and lateral hump in family Odontoceridae.

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marine and freshwater aquatic ecology and hydrobiology

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