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Fish ecology
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I am working on fish ecology in an Indian estuary. However, proper identification of species belonging to Mugilidae is very difficult particularly of the genus Mugil and Liza. Most of the references available (FAO identification sheets and some Indian keys) differentiate the species based on the premaxillae shape which is difficult to ascertain in juveniles of the family. Also the family is highly dynamic with many new or updated genus and species. So, are there any recent comprehensive taxonomic keys available for the family from the Eastern or Western Indian Ocean regions?
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Hope for u always success
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Dear colleagues
I am looking for recommendations for assessment of diet selectivity of a fish-eating bird.
I have data on relative numbers and weight, as well as sizes, of prey species estimated from bird diet samples. I also have results from gill-net monitoring fisheries (length, weight and number of fish) from the same area.
For a beginner in this field (i.e. me), what would be a straightforward way to start looking at the diet selectivity of the birds?
Are there indices that look at selectivity of both species size distribution?
Kind regards,
Karl
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Having been a fish farmer (Rainbow Trout), my recommended diet for fish-eating birds is buckshot.
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FMC (FORMALDIHYDE, MACHITE GREEN ,METHALINE BLUE)
FMCS (FORMALDEHYDE ,MALACHITE GREEN  , COPER SULPHATE ) The second equation is correct  or not ? so please informs 
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Copper sulfate is used to eliminate some types of fungi and bacteria
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Most of what I can find is on reproduction and age/growth, not on behavior. I'm researching their burrowing behavior on shipwrecks.
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Hello Michael,
I realise you asked this question a long time ago, but I am interested to know if you were pointed towards any references to Conger spp burrowing. I am similarly interested in this aspect of Conger behaviour.
Thanks,
Peter
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Fish nursery grounds are significant for the life cycle of fishes and frequently these grounds are not particularly well examined or the processes understood. The juvenile stage of fish is frequently considered to be particularly hard to work on
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Suhad Mohammed
Thanks and regards
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This is necessary for the construction of trophic links in the river.
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Like any other predatory fish at first eats zooplankton (daphnia, cladocera, copepoda). In the second year he becomes a predator.
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(Ivlev, V.S. 1961)
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Hello guys,
Do you know what package in R I can use to calculate the Vanderploeg and Scavia's Electivity Index?
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Hi,
I would be interested to learn about other people's experiences with the use of spawning tiles to collect fish eggs from the field.
I know that some species of anemonefish, for instance, will readily deposit egg clutches on ceramic tiles when placed near their breeding site (e.g. Amphiprion percula or A. polymnus), while others do not (e.g. A. bicinctus or A. chrysopterus).
What other benthic breeding species is amenable to this approach?
Thanks very much!
Gerrit
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Using fish as an example, if you have total length and age and compute a growth rate by dividing total length by age would this "age-specific" growth rate, "absolute" growth rate, etc.?
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Sorry to say but the formula is not correct; it has to be: SGR = (ln(final weight in grams) - ln(initial weight in grams)) x100 / t (in days).
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Hello
I have used the 'standard' umbrella plastic anchor/dart (developed I believe by Michael Domier) for over 10 years to PAT-tag great white sharks, with much better retention of tag by shark and less or longer premature releases, than with the original titanum 'flat arrow' anchors/darts.
Now I am about to embark in the tagging of smaller fish, Mobula rays.
My question is if someone out there has been using the smaller version of the Domeier umbrella anchor/dart, the one that is 20 mm in length as opposed to the 31 mm ('standard') umbrella dart (see link below)
I am worried that this smaller version of the anchor might not have good enough retention of tags on fish. I will be using mini-PAT tags on Mobula rays that are between 1 and 2.5 m of disc width.
Any positive or negative experiences anyone can share about using the 20mm umbrella anchors for PAT tagging will be much appreciated.
Thanks in advance.
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Hi Alessandro
Similar mix of species to what we have in the Mexican Pacific... We tagged a few M. tarapacana in Brazil and we are writing a paper about that. For those (up to 3 m DW) I see no issue with the 31 mm darts. But for the 1.5 m animals and smaller I would go with the 20 mm darts.
Good luck
Ramón
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Ecological niche modeling is increasingly important for understanding the factors that shape species distributions, as well as testing biogeographical hypotheses about species past, present, and future distributions as well as the role of ecology in speciation. However, most niche modeling work has focused on terrestrial and marine species (sound like conservation biology, in general?). I have previously used MAXENT to develop and project models of fish distributions, and the models we have published exhibited excellent predictive performance. And I am very interested in continuing to do so, particularly through coupling ENMs with phylogeographic analyses, and/or using them to inform phylogeographic hypotheses testing. However, I am skeptical of all models to some degree, and I am wanting to learn whether other techniques exist that would be more suitable for freshwater fish ecological niche modeling and paleoclimatic modeling, other than MAXENT (which is obviously most convenient for me). I am also interested in what the best data layers are for ENM analyses of freshwater habitats. I always want to learn more about these topics, so I figured I would ask here.
So, first, do such 'better' ENM models exist that could/should be used instead of or in combination with MAXENT? And, if so, what is required to run such other models, and how would the assumptions of these potentially 'better' models differ from those of MAXENT in different cases?
Second, it seems that a limitation of ecological niche modeling for freshwater taxa is a lack of sufficiently high resolution data layers for aquatic habitats. However, I am unsure about geospatial data repositories or resources for generating more suitable layers, and I would like specific advice about GIS procedures and data layers for making better data coverages. I am aware that some people are already doing this, but usually at very fine spatial scales. The broader community of ecologists and evolutionary biologists interested in fishes would therefore benefit much more from more comprehensive coverages.
FYI, I should indicate that I am not really interested in using masks over bioclimatic variables to restrict model output to the boundaries of stream and river networks, because many pilot analyses I have run on North American species suggest this does not add much or produce different results relative to running the models without such masks. So, I would prefer to avoid such discussion unless you know or can show me that doing so improves model performance. Thanks in advance for your replies. Take care.
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As an update to this question, I'd like to point out that there are some recently published papers that 1) demonstrate that it remains possible to predict the distributions of freshwater fishes (and other obligate freshwater taxa) using ENM approaches such as MaxEnt (e.g. Cao et al. 2013; Campbell and Hildebrand 2017; and several others), and 2) demonstrate that bioclimatic variables work well as a proxy of stream habitat variables (e.g. McGarvey et al. 2017).
I am particularly encouraged by the McGarvey et al. (2017) paper in Ecography, which shows that at the scale of the Columbia River watershed the performance of building MaxEnt SDMs from climate covariates/layers as proxies for variation in in-stream "environments" inhabited by fishes (which in reality include a variety of in-stream variables such as hydrological parameters) is essentially equivalent to that of SDMs based on "instream covariates" (hydrological data layers).
One common theme in some recent papers is to model only within the hydrological network, at high spatial resolution (e.g. 30 arc-seconds); however, while results from this approach are easily and beautifully visualized over smaller spatial scales (e.g. within states, regions), in my experience doing this at larger spatial scales (e.g. subcontinental scales) gives results that are much harder to visualize. At larger scales, it may be best 1) to use a discrete symbology for displaying prediction/habitat suitability within river networks, if they are used; 2) to model at the HUC rather than network scale (e.g. Cao et al. 2013); or 3) simply not to mask to hydrological network at all (make continuous plots and interpret them in the context of hydrology).
REFERENCES
Campbell, C. A., & Hilderbrand, R. H. (2017). Using maximum entropy to predict suitable habitat for the endangered dwarf wedgemussel in the Maryland Coastal Plain. Aquatic Conservation: Marine and Freshwater Ecosystems, 27(2), 462-475.
Cao, Y., DeWalt, R. E., Robinson, J. L., Tweddale, T., Hinz, L., & Pessino, M. (2013). Using Maxent to model the historic distributions of stonefly species in Illinois streams: the effects of regularization and threshold selections. Ecological Modelling, 259, 30-39.
McGarvey, D. J., Menon, M., Woods, T., Tassone, S., Reese, J., Vergamini, M., & Kellogg, E. (2017). On the use of climate covariates in aquatic species distribution models: are we at risk of throwing out the baby with the bath water? Ecography.
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I'm trying to build a library of all papers/reports that include some form of estimation of detection/capture probability when sampling fish with boat electrofishing. I'm interested in any fish species and any environment. Does anyone have any suggestions? Thanks! - Dan
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Here is another.
Schloesser et al. 2012. Heterogeneous detection probabilities for imperiled Missouri River fishes: implications for large-river monitoring programs. Endangered Species Research 16:211-224.
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We collected many fish eggs in a coral reef off the coast of Vietnam. Is that Scarus genus?
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Hi.
Do you have some publication about this eggs?
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It is a tropical freshwater snake caught in a seasonal pond 
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I caught one of these in Liberia I would say a Lycodon capucinus
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I am interested in published papers examining trends in relation to environmental variables, or just datasets that have not been published. Of particular interest is Hypomesus nipponensis, but information on any species would be great. Thanks in advance.
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I have fisheries data for both- migratory and lake smelt Osmerus eperlanus since ~1946- 1947.
Janis
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I am designing a study examining burst (maximum short period fast-start swimming) swimming in a range of fish species in a swim chamber. Many of the older papers used electric stimulus to provoke burst swimming. To me this looks like the most consistent and therefore repeatable method but I'm running into animal ethics difficulties.
Some of the newer articles use other physical stimuli (e.g. tapping the chamber, squirting with a pipette etc) to provoke burst swimming but I worry about the repeatability of these methods. Other papers purport to provoke burst swimming by rapidly increasing velocity but this must involve some level of fatigue and depends very much on the behavioral response of the species in question. 
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HI, you might look into literature on the startle response in fishes. I seem to recall several studies that used cameras and a background grid system to document the behavior in larval fishes. I don't think the goal was to measure speed, more about behavior and reaction time, but the methods might give you some ideas.
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Given that juvenile salmon feed on both benthos and drifting invertebrates, (aquatic and terrestrial), would you think primary production (chlorophyll A) could be correlated to salmonid production in rivers (such as observed in lakes) at a regional/continental scale?
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That scale is the key point. The response scale then becomes the question. Productivity per unit area would be constrained by algae productivity per unit area. But productivity per unit area is not a continental scale measure. I suspect at a continental scale, the key constraints on salmon would be temperature regime and disturbance regime. You could look at productivity at a larger scale, but I wouldn't consider productivity to be a continental scale response variable. Productivity instead responds to local scale constraints (food, prim. prodn.) in rivers where continental scale constraints are lacking (i.e. the temperature and disturbance regime are suitable).
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I received this photo from Polish anglers, Fish was caught in river of central Poland, size about 25 cm. It is not Esox lucius.
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It looks like Catostomus sp
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I have a little statistical problem to resolve. Actually I have data with distances between a target fish and three prey (quantitative dependent variable) in function of time (quantitative  input also) and I found that it is called a time serie.
My question is how to compare these three time series ? Graphically, when target fish is attracted by one of the prey, the distance between them decrease dramatically while distance with the two other preys is constant or increase slightly. How can I compare these thresse series statistically and how can I determinate statistically the time at which fish is attracted by one of the three preys ?
Thank you for answering me
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Dear Imen,
I think you should first determine what your H0 hypothesis is. As a reminder, the H0 hypothesis is the hypothesis where you consider that two or more statistical datasets are not different from each other. These datasets should be built so as to check whether a scientific assumption is most probably true or not. It is important to precisely define this scientific assumption and be able able to write it down, so that it is a yes/no assumption. Then, you can choose the appropriate statistical test to check if it is probably true or not. There is no statistical test which will emits the scientific assumption and conclusion by itself.
In your case, it is unclear what the scientific assumption is and what these datasets are. From what you explained, I could propose many scientific assumptions to look for. But I think you already have your own idea. So, as Andreas said,  I think it looks like you're trying something over-sophisticated because you did not provide the scientific assumption and what the corresponding datasets exactly are.
If you're looking for discussions  about ideas of scientific assumptions to be tested, this is another story and I would be glad to discuss it, although I'm no expert at all in fish behaviour. So, you may not learn much from me and I would probably learn much from you.
Best regards,
Neil
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For human health we use a number of general and specific tests that help understand the condition of people.  Have any such tests been done and tested for fish?
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Condition factor and indices of energetics such as hepatosomatic index are good estimates of fish health in wild. But they work only if compared to a control group 
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I was estimated age of silurus glanis from the section of lapilli. But Ages estimated by we were very higher than other researches. (etc. 9+ year in 56.6 cm Total length). Can Researchers studied on age determination of wels catfish, share their thoughts?
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Dear Ramazan,
According to your response, you have studied the age of your specimen(s) using different morphological structures and for what I understand from your messages you are concerned that your estimations are higher than those in other publications. You also have studied the feeding habits of the fish and its habitat. Apparently (my interpretation of your messages), you have the doubt that the total length reached by a specimen of ca. 9 years old is high. Why? Such TL is not unusual for Silurus glanis in other places. I have the feeling that you have done a lot of work and that you have compiled many data. Probably, the next step is just clarify what you have and try to publish a paper with the results that you have at the moment, try to interpret them the best that you can, indicating at the same time where doubts remain and why, and postulate some future lines of research concerning this species (and others).  I think that the comments from Hector are very interesting in this context.
Sincerely,
Gloria
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hi are ant author work population dynamics or stock assessment on cat fish ( Clarias gariepinus) in any place in world 
tell me  
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Dear Ahmed:
I will send you pdfs in a separate message.
With best wishes,
Ron
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TL ~45mm. Seen at Coogee Beach, Western Australia. Appeared to be "hanging" facedown near seagrass, usually in pairs. I believe they are Wood's Siphonfish (Siphamia cephalotes) but have been thrown by the colouration, which appears to be more juvenile than adult.
thanks
Glen
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It is virtually impossible to distinguish Siphamia cephalotes and S. cuneiceps with certainty based on a photograph. The most reliable distinguishing characters are the gill rakers, so you would need a preserved specimen to examine those. However, judging from the distribution range and the 11 pectoral-fin rays visible on one image, I would suggest this may be Siphamia cuneiceps.
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Morphological/physiological differences which allow it to survive in the freshwater environment of Taal Lake.
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Thank you all for your answers! Sir Uwe, great suggestion! Hopefully I, or some other researcher will try that experiment someday.
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Sex determination, loach, juveniles
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 good answer Gloria Arratia
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Hi all, 
I have collected this specimen from Mumbai coast of India. But I have a confusion with the identification of this species. Please share your experience for identification of this species.
Regards,
Rupam Samanta
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The image does not show all the characters necessary for identification, but judging from the striped colour pattern and the shape of the esca this is probably Antennarius hispidus (Bloch & Schneider 1801) (family ANTENNARIIDAE). This species is known from India, but it is also widespread in the Indo-West Pacific (Red Sea and East Africa east to Tonga).
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Dear friends,
                    These fishes were caught during the deep-sea survey in the deep waters of Andman and Nicobar islands, the depth ranges 300m-510m. if you can identify up to species level or lowest possible level.
Many Thanks in advaince
Sileesh Mullasseri
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Dear Sileesh Mullasseri:
Suggested identifications are as follows [always with some reservation as not all important characters are visible on the images]:
1) BEMBRIDAE Bembradium roseum Gilbert 1905
2) SEBASTIDAE Trachyscorpia ?eschmeyeri Whitley 1970
3) TRIACANTHODIDAE  ?Tydemania navigatoris Weber 1913
4) SERRANIDAE  Chelidoperca sp.; SPECIMEN NEEDED
5) CALLIONYMIDAE  Synchiropus sp.; SPECIMEN NEEDED
6) OPHIDIIDAE  Neobythites multistriatus Nielsen & Quéro 1991
With best wishes,
Ronald Fricke
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Small school of elongate larvae, TL ~20mm. Rottnest Island, Western Australia, March 2017. Possibly Clupeiforme (Engranulis australis, Spratelloides robustus or Hyperlophus vittatus)? Any help with identification or suggestions greatly appreciated.
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Julian and Lachlan - thank you very much for your input, regards Glen
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In case of Anabas , Ompak pabda sp larval rearing, cannibalism is a serious problem. so one ,method to  reduce cannibalism is to lower the stocking density or provide some substrate, but i want to know that is there any methods or chemicals used to reduce the cannibalism besides the above stated methods.... 
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Try to play with light intensity or changes in photoperiod.
Some nutritional studies have shown that phospholipids may reduce cannibalism in Pseudoplatystoma punctifer due to a possible satiation effect on feed intake.
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For some salmon species like Pacific salmon, they die after spawning in the wild. Do they also die after artificial reproduction in the hatchery?
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The life cycle of Pacific salmonids is characterized by one important reproductive trait: semelparity. This means that they spawn only once. The purpose of this reproductive strategy is to maximize reproductive success by allocating all energy resources to the generation of gametes. This has a substantial cost to the animals: death after spawning. All Pacific salmon die following spawning because the changes in hormone plasma levels, including reproductive hormones and corticosteroids, oriented to reproductive success, are significant causing rapid ageing and physiological deterioration resulting in death. Therefore, Pacific salmonids used in farming operations (aquaculture) also die following spawning. This is the result of natural, physiological causes, and also because the gametes are regularly obtained by cutting the fishes’ abdomen to reach and empty the ovaries. Sperm may be collected from males by pressing the abdomen and releasing the semen, but these males are discarded also because their condition after maturation and spermiation is very poor and would result in death anyways.
All Pacific salmon die following spawning because the changes in hormone plasma levels, including reproductive hormones and corticosteroids, oriented to reproductive success, are significant causing rapid ageing and physiological deterioration resulting in death. Therefore, Pacific salmonids used in farming operations (aquaculture) also die following spawning. This is the result of natural, physiological causes, and also because the gametes are regularly obtained by cutting the fishes’ abdomen to reach and empty the ovaries. Sperm may be collected from males by pressing the abdomen and releasing the semen, but these males are discarded also because their condition after maturation and spermiation is very poor and would result in death anyways.
Other salmonids, such as Atlantic salmon and rainbow trout are iteroparous, meaning they can mature and spawn more than once in the wild. This characteristic can be used in the artificial reproduction of these fishes by spawning them under anaesthesia, keeping them alive, and allowing them to recover (a process called "reconditioning") and be able to mature and spawn again the following year.
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Dear Friends
I am working on the osteology of the fish species John Dor, Zeus faber from different countries.
I appreciate very much the assistant of any friend who can get me an x-ray fro 3 specimens of the fish species Zeus faber from the waters of the following countries:
Brazil, Uruguay, Argentina, Chile, Peru, Ecuador, Namibia, Congo, New Caledonia, Fiji, and Papua New Guinea
Laith A. Jawad
Auckland
New Zealand
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Sorry Dear jawed ...so maybe usful to other researchers 
Regards 
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I am calculating biomass differentiation associated with different fishing mortalities but it is too hard to understand the FAO or other resources.
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I'm relating  the occurrence of micr plastic in the gut of fish species to its total length to see if there's a relation. I feel that the gape size in relation to the micro plastic would be a better comparison to make and therefore, using the data of total length and occurrence of micro plastic, is it possible to obtain a gape size? 
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You can find 61 species' TL-gape relationships in my publication, as well as general ones based on species' functional trophic groups:
KARACHLE PK & STERGIOU KI. 2011. Mouth allometry and feeding habits in fishes. – Acta Ichthyologica et Piscatoria, 41 (4): 255-275. (attached)
To my knowledge there is no such general relationship .
Regards
Voula
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Deep-water fishes are commonly considered widespread and not a speciose group, but could this conservative group be used as a good (or even the best) indicative of a center of speciation? The recent increase of deep-water elasmobranch descriptions and records off the Brazilian coast (119 to 162 species from 1989 to 2007) has raised the question if there is a much higher diversity than previously expected. 
What group of fishes will be considered for your project? Thank you very much!
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I am uncertain whether deep water fishes can be considered more diversified or not, but part of the problem rely on the level of knowledge of certain regions in specific oceans. For instance, in some places (e.g., the Pacific coast of South America) deep sea fishes are very incompletely known. Some recent deep-sea expeditions have discovered many new fishes (most of which still remain undescribed) but also new records for non-deep see waters. In this case, many of those new records have been explained as results of El Nino or La Nina Phenomenon or currents that have significant changes in the marine biodiversity. To my best knowledge, the area of origin of a group is something more complex than to be explained using number of species in an specific area (e.g., deep-sea waters).
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In an experiment that proposes to elucidate questions related to the choice of habitat by young fish forms, which is the ideal time interval to support your study: 2-3 days, a week or even 15 days? And why? Can someone help me? Grateful!
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Its unclear from your post exactly what stage of life you are planning to study (e.g., larval stage or juvenile). In any regard, a few things you should consider when developing your study are 1) The life history of the fish or fishes in question (e.g., for the stage you are interested in what is the site fidelity of the fish (i.e., are they highly mobile or do they tend to stick to one area; on what time scale is this behavior? This will help you figure out the appropriate time interval). Other aspects of life history should be important as well  2) the scale or scales of habitat you are interested in (regional, landscape, stream reach, mesohabitat, and microhabitat associations may be of interest to you). I assume you know the scale(s) of interest here but it is hard for me to offer advice without this information or more information about your objectives. 3) another thought is that if you think multiple time scales may be important (2-3 day, week, and 2 week scales) then you could design a study to look at habitat use on all three of those time scales with some kind of nested design. A lot of this depends on the details of your questions and objectives.
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We have a collection of around 70 species specimens from 20 families; all from Vembanad Lake, Kerala, India.  We would like to know what all are the effective long term preservation techniques, either using Isopropyl alcohol or something else; except Ethanol (due to availability issues in Kerala). We would like to display these wet specimens too, since there are no collections of this kind available in the vicinity.
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Dear Anu, We also changed our fish collection from formalin to alcohol some years ago. If the fish were fixed in formalin first, there no problem with conservation in alcohol. Use glass jar only as plastic one deteriorate after years. Just make sure to use very good lid on top of your jar to prevent as much as possible evaporation. It will occur anyway so you need to have a well ventilated  room for health and safety. A special care should also be given to fire risk analysis and prevention. In case you do not want to put your specimens anymore in formalin and you want to fix them directly in alcohol make sure you have enough volume because alcohol is not very for fixing tissues. You will need a large amount of alcohol compare to the volume needed with formalin. I hope this can help you. 
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Water accommodated fractions of diesel oil are highly volatile and insoluble with water. I have to conduct acute and chronic toxicity testing for shrimps, mollusca and fishes in juvenile stages by adopting flow through methodology. 
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Dear Dr Vasanth,
You need to establish some more boundary parameters before the experimental set-up is constructed. (see example of set-up) Journal of Environmental Protection
Vol. 4 No. 7A (2013) , Article ID: 34701 , 7 pages DOI:10.4236/jep.2013.47A008).
It is important to understand the water and the diesel.  Do you plan to feed you test organisms?
1) What sort of water? Fresh, Brackish, Sea? exposure of some materials to 30 days of saltwater could cause problems
2) Diesel comes in grades -(https://www.dieselnet.com/standards/in/fuel.php)   the water soluble portions differ from grade to grade and by how the refining process was done - this can impact volatility which has implications on health and safety in the preparation of materials (and possible contamination of the lab).  You would need to know what sort of diesel you are using and to characterize it for scientific rigor.
Please see the following sites for more information
Kind regards and good luck
Prof Chris Gordon
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I search into Articles and there is no detailed information for age at maturity calculation protocols, and I didn't calculate GSI because my sampling wasn't monthly basis. So Is that make any trouble in that calculation?
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Hi Milad,
you do not have to calculate GSI to estimate age at maturity. You need just to know the age of every fish you sampled (in months or in years, depending on life expectancy) and physiological status (adult, mature vs immature). Then you need to calculate a sigmoid curve describing changes in percentage of adults in the sample with age (beginning from zero in juveniles, eventually it will be 100% when all fish become adults). The age when this curve crosses 50% is age at maturity.
Best regards,
Vlad
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It was collected in Iquitos, Peru. 
Thanks a lot for your help!
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The species well agrees with the original description of
Ctenobrycon hauxwellianus (Cope 1870)
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We are planning to change the traditional paper sheet and pencil by waterproof or rugged tablets to record survey data onboard during oceanographic surveys, including biological samplings. We would like to know your opinion about brands, models, ease of use and existing apps for introducing data. Thank you!
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See: David R. Gloeckner,
 IMPROVEMENTS TO DATA COLLECTION IN COMMERCIAL FISHERIES USING ELECTRONIC REPORTING METHODS: COST/EFFICIENCY AND IMPLICATIONS FOR USE IN ECOSYSTEM MANAGEMENT
He has a profile on ResearchGate and heads the NMFS SEFSC Electronic Logbook program for collecting commercial fisheries data.
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I would like to hear from anybody, who has an access to fish samples from Zanzibar. Interested in collaboration to do research on fishes of this island. I have several research ideas to apply on its fish fauna.
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Dear Azza
Many thanks for your email and for your intention to do researches with me.
I am sorry I did not make clear in my post that I need people already living in Zanzibar for collaboration so we can use fishes from there.
It seems that you living in Egypt and obviously it not possible for you to get access to fishes of Zanzibar.
This is will not stop our collaboration. I have several research ideas that I would like to apply on fishes of Egypt. I already have published some papers on fishes of Egypt, but there are still more ideas to do.
I am a fish taxonomist and interested in fish morphology.
I would like to work on the morphology of the otolith of fishes of Egypt and produce an atlas. Do you think you can work in this line?
I am looking forward to hearing from you so we can discuss further the possibility of collaboration.
Please write to me at my email address
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Very few strict herbivores, detritivores (and young usually are invertivores)
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Dear Khalidah,
Thanks for your attention and scientific information.
Best wash.
AK Resen
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I will be part of group assessing the current state of a fishery in a floodplain system in Central Africa. We have approximately six weeks.
One of the objectives is to establish a baseline of fish biomass, diversity and age profile. We won't really be able to carry out a standard scientific survey (i.e., with nets of consistent length with different mesh sizes). Instead, we plan to record catches from fishers (who fish using gillnets from dugouts).
I would be grateful for any input regarding
(a) the feasibility of this approach and
(b) databases (e.g., PASGEAR) that might be suitable, not only for our research but that is user-friendly in case the data collections continue after our research finishes. Thanks!
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Hi James,
sounds like you want to do a multi-species approach. Fishing with different nets by different people, especially gill-nets, may make things complicated. Do you have any possibility for capture-recapture experiments? Are the species you want to investigate suited for that? Do you have any time series of your data? Or you may think about catch-depletion methods, if that is feasible, a brief description for a start is found here: http://derekogle.com/fishR/examples/oldFishRVignettes/Depletion.pdf.
I don't know PASGEAR, but from its description it sound quite adequate. I also once worked with FiSAT II from FAO, but probably you know this already? FiSAT is better suited for analysis than for data storage. For analysis there are also plenty of R packages available, maybe fishR would be good. At least it's free, even though you might need people who know how to work with it.
Anyway good luck with your campaign!
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Beta carotene should be safe and pure to be included in fish feed.
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Femi sir i think ethanol will extract beta carotene with a fair bit of yield and the advantage that we can get rid of it quickly before feed formulation.
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I need expert opinions in selecting the best stress markers to use as indicators for stress in fish in natural environment and under culture conditions.
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Cortisol and Glucose
Cortisol and glucose are two of the most common stress indicators. In spite of the extended use of these indicators and their acceptance, some inconsistencies have been reported in the results of several experimental studies, much of them associated to undefined and uncontrolled variables which may alter the response in secretion of cortisol and glucose into the bloodstream. Most of those factors are not considered as direct stressors but have an effect on the intensity of the response which makes them a source of error. Some of those factors are related to metabolic changes in the organisms as an adaptation or acclimation mechanism; other are extrinsic to the fishes; other sources of error are caused unconsciously by the researcher during manipulation or due to inadequate control of variables, and may lead to intrinsic changes.
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Hi! We're working with a substrate-brooding fish (the two-spotted goby Gobiusculus flavescens) which is nearly an 'annual': almost no adults survive to breed in two seasons; in some populations likely none. However, they can breed repeatedly (theoretically up to 6-7 times) over their single breeding season.
I've tried to find out which fishes may have a similar life history: breeding for only one "season" (requires distinct 'breeding seasons'), but repeatedly in that season. I'm struggling to find any other such species (except for three other benthic gobies: sand-, common- and painted-). Therefore, I'd be extremely glad if anyone could help out!
Any info about fish with this sort of life history would be greatly appreciated. Substrate-brooders w/male care would be of particular interest. If you know of relevant references, please provide sufficient info so I can search it up.
Excited to see what this question brings up! Thanks a lot on beforehand to anyone helping out!
All the best,
Trond
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Some killifish, such as Nothobranchius furzeri, are short lived (annual) and breed during the rainy season. See Valdesalici & Cellerino (2003) Proc. R. Soc. Lond. B (Suppl.) 270, S189–S191.
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For example, climbing perch (Anabas testudineus) is well known for lateral migrations into the floodplains during the spawning season (the flood) and then returning to the rivers when the floodwater begins to recede. This phenomenon is often mentioned in literature. OK, but how this fish can set the trend of motion? At random?
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I don´t know about the climbing perch but in case of glass eels (Anguilla anguilla), climbing behavior during their upstream migration seems to be linked with increased cognitive abilities (increased expression of cognition-related genes in brain), which in turn could be explained by a switch in the perception of environemental cues. Indeed, those fish rely a lot on the olfactory cues in the water, but they could be prone to use other (visual?) cues once out of the water. How do they choose the direction? They could follow the same climbing path than the previous ones: each fish leave a bit of mucus while climbing the wall. How do the first fish choose the direction? Probably by the trial/error process, led by high motivation to migrate upstream (thyroid hormones) or to explore the new environment (boldness/ risk-taking behavior). The whole process by which the "best" climbing direction in group is established and maintained could be similar to the one in ants (shortest way->more attractive and volatile pheromones remaining on the path-> their "run towards the strongest pheromone"  closing the loop).
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s
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 I suggest that you enter in my profile, year 1992 , and download a pdf of about 100 pages on the caudal skeleton of Salmonidae, including the development of the caudal skeleton of Oncorhynchus and other salmonids. In Journal of Morphology.
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In many, perhaps most, substrate-brooding fishes with paternal care, several females may deposit clutches (ie, batches of eggs) in the same nest, to be fertilized (mostly) and cared for by the same (nest-holding) male until hatching (after which there is usually no care).
Thus, each female adds one clutch of eggs to the nest. But what term should be used for the "combined egg mass"? Oftentimes, there is no way (except by DNA) to know which eggs are laid by which female, or indeed how many females have spawned in the nest, so one needs a term to describe 'the sum of clutches'. Or, said another way, a term for the amount of eggs cared for by the male (the basis for calculating his reproductive success).
I haven't been able to find any consistent terminology on this matter, and would very much like to have one, at least one to use myself. Oftentimes, the term clutch seems to be used to cover BOTH each female's clutch, and the combination of clutches from all females. Other times, the term brood is used, but it is often not clear what exactly that is supposed to mean. In the bird literature, brood would be hatched yet still dependent young in a nest and clutch the eggs before hatching; in fish that obviously doesn't work out - the term 'brood' must have another meaning in fishes. But is that just as a synonym to clutch, or does it mean something else.
To me the use of these terms in the fish literature seems a complete mess. But maybe there are proper definitions and conventions that I have missed? 
Help!!! (ie, any advice greatly appreciated)
Best wishes, Trond
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 For the egg mass cared by a male fish, I would not use the term clutches as in some demersal spawners (i.e. some blennids, some pomacentrids,etc.) females may parcelize their clutches (i.e. the group of simultaneously mature eggs laid)  in the nest of  more than one male. I would  use the term "brood", explaining in the text what you mean. Anyway,  I agree with you that the language is not standardized
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I am specifically interested in these U.S. FDA-approved products: Formalin-F, Formacide-B, or Parasite-S. Is one of these products superior to the others?  Do all work equally well in saltwater?  Are other parasiticides more effective than these?  I'm simply looking to extract ectoparasites from "healthy" wild fish, not to treat infested fish.
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Hi Charles
The freshwater dip shouldn't kill the host as it is only a temporary osmotic shock. That said, if the hosts are moribund or otherwise compromised then any procedure is going to increase the risk of mortalities. What is the target host species? If you are dealing with a commercial interest then freshwater is probably going to be the most acceptable method as there are obviously no issues with chemical use approvals and retention times. I have used this method repeatedly on a large diversity of species including some very sensitive ones (and juveniles) with good success. Your concerns should be covered under a university ethics approval, which I would imagine would be acceptable to your collaborators? Under all methods they would need to acknowledge some possible mortalities, but that these would be avoided were possible. If I can be of any future assistance please just shout - I am more than happy to help.
Best regards, David
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I'm curious if any recreational divers - I know its good sport to kill and consume these fish - or researchers have ever identified vocalization in Lionfish. I've read that they are very static as individuals and don't travel more than a dozen meters or so from their birth site, so I have to believe they are attracting mates somehow.
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According to Jud & Layman 2012 lionfish are capable of making an audible noise when disturbed.
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Nemo drill driver 2 Does anybody have any experience in using the Nemo drill diver 2 for underwater drilling. I am aiming to anchor down some cages onto the seabed composed of limestone at depth of about 8 m (i.e. relatively soft rock). Now I have seen this drill on the internet
and it appears it could be a good alternative to the pneumatic drills which are more expensive and their use appear to involve far more logistics. I would love to hear some experiences of drilling underwater and which pieces of equipment work best.
Many thanks already
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Hi Hilmar,
We do quite a bit of drilling underwater for our monitoring site set up. We have a spitzner drill.
Nemo drill looks good in theory. the video looks pretty convincing. If it has a good hammer action it should work. if not then it is prob useless. we had an old underwater drill with no hammer action and it was ineffective. the spitznas is not too cumbersome. need a few spare cylinders to take down with you or with your buddy. got video of it somewhere if you want to see. let me know if I can help anymore. cheers, Charlie
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I came across several papers that use both formula and I have mixed thoughts on its applicability.
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Hi Palla,
I can certainly understand your concern and definitely it is a valuable question before fixing your methodology. As per my understanding GSI (Gonado-Somatic Index) is a measure to understand the gonadic growth against the somatic at a given period of time. Now consider a case where the fish has too small sized gonad,  the denominator that should consider the somatic growth gets too large to attain a value and troublesome to the measure. Thus to increase the visibility of the gonad growth and keep the denominator as low as possible, the gonad weight is subtracted from the total weight. Or otherwise the other formula is valid for any kind of fish you study.
Hope this helps you.. 
Best wishes
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The Catalog of Fishes entry is as follows:
gnanadossi, Ariosoma Talwar [P. K.] & Mukherjee [P.] 1977:432, Fig. 1 [Indian Journal of Animal Sciences v. 47 (no. 7); ref. 27708] Off Madras, India, depth 250 meters. Holotype (unique): ZSI F.7146/2. See Das 2003:350 [ref. 27706]. •Valid as Ariosoma gnanadossi Talwar & Mukherjee 1977 -- (Psomadakis et al. 2015:148 [ref. 34104]). Current status: Valid as Ariosoma gnanadossi Talwar & Mukherjee 1977. Congridae: Bathymyrinae. Distribution: Pakistan and India. Habitat: marine.
We consider the species as valid in CONGRIDAE; the species name, however, should read Ariosoma gnanadossi.
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I am using vegan package (R) and radfit function to show species richness and evenness across several sites. I am trying to figure out how to calculate slope of a model using radfit (see example below) and how to compare slopes of models for different sites if they are significantly different.
For instance, I want to calculate slope (as an integrative measure of species richness and evenness) of site 5, 6 and 10 in the data below and then compare the three slopes. I modeled using rad.preempt (line).
Thanks
library(vegan)
library(BiodiversityR)
data(dune)
mod.5 <- rad.preempt(dune[5,])
plot(mod.5, pch=20, col="black")
points(rad.preempt(dune[6,]), pch=20, col="blue")
lines(rad.preempt(dune[6,]), col="blue")
points(rad.preempt(dune[10,]), pch=20, col="red")
lines(rad.preempt(dune[10,]), col="red")
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Hello,
I might want to take a look on Biodiversity R package, it has graphical interface and includes vegan as well as very detailed and descriptive manual
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Captured 22/09/2016 in breackish par tof the Zeeschelde (Belgium).
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This is a polynemid fish. Not all of the important characters are visible, but it may be Galeoides decadactylus (Bloch 1795). That species was previously known from the Mediterranean Sea and the eastern Atlantic from Morocco to Namibia, so this would be a range extension.
For identification, I would recommend the key provided by Motomura 2016.
Reference:
Motomura, H. 2016. Polynemidae. Pp. 2621-2628. In: Carpenter, K. E. and N. De Angelis (eds.): The living marine resources of the Eastern Central Atlantic. Volume 4. Bony fishes part 2 (Perciformes to Tetradontiformes) and Sea turtles. FAO Species Identification Guide for Fishery Purposes, Rome, FAO. [Orders and families by individual authors.]. i-xiii + 2343-3124.
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In the area around the Isthmus of Santa Catalina Island Rock Wrasse (Halichoeres semicinctus) has been observed as a cleaner fish. There are not a lot of Senoritas here at this moment and the Rock Wrasse are acting like cleaners for a whole host of other fishes. There is one paper from the 70's from fish and wildlife that seems to claim that this is very uncommon and it is most likely on individual responsible foe this. I am studying on Catalina for the semester and might pursue this as my research topic. I attached the file.
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Yes, Elizabeth, Ted Hobson published those observations many years ago. Observations that were made in the cove at the Wrigley Marine Science Center - where you are right now. I know of no other original literature on rock wrasse cleaning. Cleaning behavior by CA fishes is covered in Chapter 21 (by John McCosker) in the book Ecology of Marine Fishes: California and Adjacent Waters edited by Allen, Pondella, & Horn (2006).
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What is basic difference between fossil fish mouth Plate of Genus - Diodon and Chilomycterus . Inbox me relevant literature.
Thank You 
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Thank you so much  ORANGEL AGuilera Sir for your informative input.
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I just cleaned a S. glanis skull, and I cannot find a good paper on the osteological anatomy of the species. Could anyone recommend me some, or help in identify the questionable bones?
Thanks;
Márton
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Hello, 
You can also use this illustrated database: http://fishbone.nottingham.ac.uk/
Silurus is among the entries. 
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During a research regarding the influence of salinity on Cyprinus carpio (checked metabolic rate on 2 different exposures 10ppt NaCl and 10 ppt Seasalt) we noticed that during the exposure of NaCl a lot of the carp lost scales on and near the lateral line. We think this has to do with the trans epithelial excretion of NaCl, but can't seem to find any literature about this. Can someone help?
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You should know the salt tolerance tendency of selected fish. freshwater stenohaline fish can't bear such level of salt and ofcourse excess of everything is bad! before starting experiment on these creatures you must know and read enough literature for successful output. 
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We're currently studying growth of larval/juvenile wolffish, which were hatched from wild-caught, fertilized egg-balls in Icelandic waters earlier in the year.
At the moment, we're not sure if the fish are the young of A lupus or A minor, and we're happy to hear your opinion.
The picture is taken at about 150 days post hatch
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Hello everybody, I found a species identification guide (NAFO Wolffish Species Guide) and a wolffish identification guide by Fisheries and Oceans Canada (attached). The guide explains how the species can be identified on the basis of differences in the number and relative position of the vomerine teeth (the strong molars in the upper jaw). I took one dead fish and inspected the teeth and indeed, there were five sets of vomerine teeth just as described for spotted wolffish. There is, however, also a possibility that there may be some common wolffish in the group since the fish came from two separate egg clusters.
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any general files will do, though preferably something from a reputable source.
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Cornell Bioacoustics and the  British Museum of Natural History have big sound libraries.
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Although being a zoologist and not a pest exterminator I recently got some inquiries how to control Dreissena mussels. There is indeed a lot of valuable literature about this topic but few information on practical experiences. Can anybody in the research community recommend me a link or an enterprise that works on this topic reliably and eco-sensitive? It would be helpful if this company also operates in Europe.
Best regards, Otto
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Good responses already present, I offer a joke to lighten up the topic a bit:
What's the difference between zebra mussels and love?
Answer: Zebra mussels really ARE forever. 
(adapted from an earlier version comparing love to Herpes, students display very nervous laughter at this) 
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I need to detect the presence of tetrodotoxin from crude puffer fish extracts through GC-MS. I need to know if only MSTFA (N-methyl-N-TMS-triflouroacetamide) should be used for derivatization purpose for this experiment or any other silylating agents can be added for derivatizing the toxin in the extract?
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Hi Jan,
I tried once silylating tetrodotoxin from fish tissues. I processed my tissue extract samples as per the standard procedure and finally evaporated it to dryness. But the final residue which has to be dissolved in the silylating agent is not getting dissolved in it. The residue remains detached from the silylating agent and that is my problem now. Can you help me to sort this out?
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Hi all,
I was really intrigued yesterday after I fished this... bowl?
I first thought it was a sponge, but the structure does not fit at all. Today I asked some colleagues of mine, the idea came about a sea cucumber. But I am not that convinced. 
What do you think ?
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Found it, it is a Turnicate ! :)
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How ecological stoichiometry can be used to analyse trophic ecology of predators, like fish?
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Dear Mário,
Michał pointed out already to a lot of relevant literature. So I don't repeat those here, but attach some articles that dealt specifically with fish and ecological stoichiometry.
Because Michał also mentioned papers from nutritional geometry framework, I also attach one of my recent papers that attempts to bridge ecological stoichiometry with nutritional geometry as related and complementary frameworks in nutritional ecology.
Best regards,
Erik
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Hi, I'm in doubt with the identification of this fish. Using identification guides it seem Lipophrys pholis, but I'm not sure...
someone could help me?
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As the other species of Genus LipophrysLipophrys trigloides (and Lipophrys pholis) has no supra orbital tentacles.   
According to Daniele, in Mediterranean, Lipohrys pholis  is essentially distibuted around  Gibraltar (Francisco S.M., Faria C., Lengkeek W., Vieira M.N., Velasco E.M., Almada V.C., 2011, Phylogeography of the shanny Lipophrys pholis (Pisces: Blenniidae) in the NE Atlantic records signs of major expansion event older than the last glaciation, Journal of Experimental Marine Biology and Ecology, 403, 14–20). However, in fishbase, the distribution includes the balearics.
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what signs we should look at to decide when the dry food should be offered to fish after feeding them live food and if there any method to make them eat the food?
Many thanks 
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thank you all for your answers. our fish are weaning normal now. Apparently they like higher density 
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Does anyone have a solid theory regarding the distinct coloration in juvenile Zebra sharks? The juveniles are striped, whereas the adults are spotted. As far as I know, no data is published on their habitat differences explaining color. A yellow-lipped sea krait, Laticauda colubrina is present in much of the S. fasciatum range. Could mimicry of this venomous reptile be a relevant explanation? This is already performed by several octopus species to my knowledge.
Image links:
(S. fasciatum juvenile)
(L. colubrina)
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Hi Leon!
I have read a similar article (which I will attach here) during an Ecology class in my university in the Philippines. It's about the difference between a juvenile and an adult shrimp (Latreutes fucorum) in terms of the way they resemble their environment. Juveniles tend to use mimicry; while adults tend to use camouflage. The reason behind this is that the adults start to outgrow the parts of their habitat that they mimic so an ontogenetic shift has resulted in their reliance on camouflage, rather than mimicry. The distinct coloration between a juvenile and an adult may be due to, therefore, differing survival techniques that have adapted to be more effective with respect to their respective sizes. 
Peace out!
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Hi, Someone could help me in the identification of this fish. I found it in a rocky bay at 1m depth in Ionian sea (Mediterranenan Sea). It is probably a juvanile, it was around 7-10cm. Thank ou very much
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hello
i'm pretty sure that it's a Spondyliosoma cantharus with a dark "fur" typical of individual in shadow area, or at night
here you'll found a link to an atlas we have published on fish post larvae and some juvenile in northwestern mediterranean.
page 141 you'll found the species
all the best
romain
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I am comparing the Von Bert life history parameters of three populations of a single shark species. In two populations I have negative values for the birth size estimate. One population (Western Cape) is biased towards older, mature individuals whilst the other (Eastern Cape) is biased towards small juveniles. The Eastern Cape population also shows an unrealistically large estimate of asymptotic length which I have found to be cause by small sample size and a bias towards small specimens. 
I am well aware of the fact that it is not possible to have a negative birth size. I cannot, however, find information as to why this might happen and if there is anything that can be done to correct these values. 
Can anyone shed some light on these unrealistic asymptotic length and size at birth estimates?
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T0 is the time at length=0, not the length at time=0.  This is a common misconception.  As such, it should always be negative, as fish have length at hatch (i.e. length at time=0 is positive).  If you truly mean that the length at time=0 is negative, then yes, you have a problem.  One solution is to add data for size at birth ( length at time = 0) using values from the literature and "fix" the size at time=0 to that size at birth.  This can be done in many modeling platforms by fixing the y intercept.
If you are only trying to use your growth curve for estimating age from size of small animals, I wouldn't worry about the poor fit to L infinity, as you will never extrapolate beyond the range of your data.  If this is a curve you intend to publish, then you will need more representative samples.
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is it good measure that kernel distribution estimator using for length frequency distribution of fishes ?, what is the importance of band width in kernel density ?
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Hi Sileesh
Yes, using kernel density estimation is advisable when you analyze length frequency distributions (or any other type of frequency distributions) because it allows you to quickly explore and to characterise the distribution of your dataset. Two issues that should considered with this approach: a) type of kernel to be used (there is a bunch of them, i.e. Gaussian, tricube, triweight), b) Bandwith selection. I will just focus on the bandwith issue. See an example in the attached figure. I used R to create a toy dataset for a random variable with a tri-modal distribution (n = 3000 observations), that is simply the combination of three random variables with normal distribution with mean 0, 3 and 6, respectively, and SD=1 in all cases. 
When your bandwith is too high (bw = 2 or 1), the resulting frequency distribution showed by the kernels indicate a rather unimodal normal distribution. The tri-modal distribution becomes apparent only when you decrease the bandwith. Of course decreasing the bandwith too much increases the noise. I know there are some approaches to estimate the optimal bandwith, but honestly I am not familiar with them. Said that, if you are only interested in exploring length distribution data, kernel density estimation may be very useful technique in help you identifying the presence of multiple size cohorts (or the lack of them). 
Good luck with your research