Fish Ecology - Science topic

Hi guys,

I have raised a question regarding selecting proper statistical methods for the temporal analysis of community composition data. My study site is a river, and it has been implemented with a fishing ban a few years ago. On the other hand, by monitoring water quality parameters, we found the river has also benefited from slightly improved water quality in recent years.

After a long-term fish survey, we found significant changes in fish communities before and after the fishing ban (with one-way PERMANOVA analysis). However, we are not sure what is the main driver for the changes, the fishing ban or improved water quality.

I know that canonical correspondence analysis (RDA/CCA) has been widely used to determine the relationships between biological communities and associated environmental factors. I'm wondering if it's reasonable to consider time series as an environmental factor, by splitting sampling date into before and after, and using it in the CCA analysis with other water quality parameters (please find attached the figure for explanation). However, I didn't find an example for this, which makes me wonder if it's not correct.

Or if there are better statistical method that commonly used in ecology studies to slove this query？

Many thanks!

Rui

Hi folks,

My colleague has just asked me for advice regarding analyzing his BRUV (baited remote underwater video) dataset. It's a video camera fixed on a structure, used to record marine fishes passing by or attracted to the attached bait. It resulted in a wide dataset of species assemblage (lots of zeroes, lots of species columns). He has generated an NMDS ordination plot and ANOSIM to analyze his species assemblage dataset. He sees a spatial (geographic) separation of species composition through these methods.

Now, he wants to understand what drives this assemblage. He has additional benthic composition dataset (% coral, sand, rubble, etc.), current strength, depth, and more abiotic data. His coauthor is suggesting fitting envfit vectors on their NMDS and use the p-value of said vectors. I don't think this is a good idea, but I'm not well versed in this topic so I couldn't explain it sophisticatedly. I think because the vectors are "retrofitted" onto the ordination, the p-values are therefore not explanatory toward the species assemblage.

The alternative I could think of is running PERMANOVA or a model. The problem with the former is that the benthic composition dataset are related to each other (7 different variables, but all add up to 100%) so they're not independent of each other.

I'm wondering if anyone has any solution to this/or can add to the explanation. Would it be reliable to run a PERMANOVA? Should he be transforming his benthic composition dataset first? Or would he be better off creating a model, and if yes, which kind?

Thanks!

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?

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

Most of what I can find is on reproduction and age/growth, not on behavior. I'm researching their burrowing behavior on shipwrecks.

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

This is necessary for the construction of trophic links in the river.

FMC (FORMALDIHYDE, MACHITE GREEN ,METHALINE BLUE)

FMCS (FORMALDEHYDE ,MALACHITE GREEN  , COPER SULPHATE ) The second equation is correct  or not ? so please informs 

(Ivlev, V.S. 1961)

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

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.?

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.

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.

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

We collected many fish eggs in a coral reef off the coast of Vietnam. Is that Scarus genus?

It is a tropical freshwater snake caught in a seasonal pond 

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.

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. 

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?

I received this photo from Polish anglers, Fish was caught in river of central Poland, size about 25 cm. It is not Esox lucius.

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

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?

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?

hi are ant author work population dynamics or stock assessment on cat fish ( Clarias gariepinus) in any place in world 

tell me  

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

Morphological/physiological differences which allow it to survive in the freshwater environment of Taal Lake.

Sex determination, loach, juveniles

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

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

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.

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.... 

For some salmon species like Pacific salmon, they die after spawning in the wild. Do they also die after artificial reproduction in the hatchery?

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

I am calculating biomass differentiation associated with different fishing mortalities but it is too hard to understand the FAO or other resources.

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? 

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!

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.

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. 

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?

It was collected in Iquitos, Peru. 

Thanks a lot for your help!

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!

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.

Very few strict herbivores, detritivores (and young usually are invertivores)

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!

Beta carotene should be safe and pure to be included in fish feed.

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.

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

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?

s

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

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.

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.

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

I came across several papers that use both formula and I have mixed thoughts on its applicability.

Ans

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")

Captured 22/09/2016 in breackish par tof the Zeeschelde (Belgium).

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.

What is basic difference between fossil fish mouth Plate of Genus - Diodon and Chilomycterus . Inbox me relevant literature.

Thank You 

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?

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

any general files will do, though preferably something from a reputable source.

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

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?

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 ?

How ecological stoichiometry can be used to analyse trophic ecology of predators, like fish?

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?

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 

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)

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

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?

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 ?

I am writing a paper that compares smolt/adult values for Chinook salmon in Redwood Cr (Humboldt Co., CA) in two recent drought years. Our smolt/adult values decreased considerably when adults could not reach the mid/upper basin. I used two DIDSON sonars (one in upper basin, one in lower basin), and 3 smolt traps. I would like to reference others who have determined smolt/adult values in other streams.

I need the species list and the amount captured

Dear All

I am nearly finished my book on the dangerous fishes of the east and southern Arabian Peninsula.

For this book, I need to put images for the species dealt with in the book. The total number of fish species mentioned in the book is 134. I managed to get 85 images and I need to get the remaining 49 images.

The book will be published by an international publishing house.

I would be much grateful for anyone has images for any of the species mentioned in the following list and would like to send to me to include it in my book. All images will acknowledged.

Images from the fish markets, landing sites and studio are all welcome.

List of fish species/ images required

1. Stegostoma fasciatum

2. Nebrius ferrugineus

3. Carcharhinus amblyrhynchoides 

4. Carcharhinus amblyrhynchos

5. Carcharhinus galapagensis

6. Eusphyra blochii

7. Heterodontus omanensis 

8. Heterodontus ramalheira 

9. Anoxypristis cuspidata 

10. Pristis pectinata 

11. Pristis zijsron  

12. Gymnothorax flavoculus 

13. Gymnothorax griseus 

14. Gymnothorax herrei  

15. Gymnothorax megaspilus 

16. Gymnothorax phasmatodes

17. Myrichthys colubrinus

18. Sphyraena acutipinnis

19. Sphyraena flavicauda  

20. Sphyraena qenie

21. Canthidermis macrolepis 

22. Melichthys indicus  

23. Rhinecanthus assasi 

24. Eupleurogrammus glossodon 

25. Eupleurogrammus muticus

26. Strongylura strongylura

27. Tylosurus choram

28. Acanthurus leucosternon

29. Acanthurus tennentii  

30. Naso fageni 

31. Heteronarce mollis 

32. Torpedo adenensis 

33. Torpedo marmorata  

34. Torpedo panthera 

35. Torpedo sinuspersici 

36. Anodontostoma chacunda 

37. Dussumieria acuta  

38. Thryssa hamiltonii 

39. Ruvettus pretiosus 

40. Cyclichthys orbicularis

41. Silurus glanis  

42. Colletteichthys dussumieri 

43. Bifax lacinia  

44. Pardachirus marmoratus

45. Himantura imbricata 

46. Himantura jenkinsii 

47. Aetobatus ocellatus

48. Netuma thalassina 

49. Scorpaenodes evides 

Regards

LAITH A. JAWAD