Probably Padogobius

Dear Phillip,

You have a big problem in your hands because identification of fish larvae is not easy, but, in this special case you are working with larvae that are already partially digested. I would suggest that you try photographing the larva showing the position of the fins as well other features in lateral view.

To your questions:

1. I am uncertain if there is a key for larvae including all species in your list.

2. Yes, it is helpful to know the reproductive periods of the different species involved. However, this is relative because the reproductive periods can change from year to year depending on changes in temperature and other environmental factors. Nevertheless, it could be helpful if you have information on the reproductive cycle of the species in your list.

3. Yes, it is possible but it requires training in larvae identification. However, you cannot forget that you are working with partially digested larvae and depending on the degree of digestion, the difficulties in the identification increase.

With my best wishes to your research!

Gloria Arratia

Hi Phillip,

Depending on your budget, genetic bar coding could be cost-effective. I've included a few references for your consideration.

I've also attached a manuscript that supports DNA techniques for partially digested fish larvae, even when morphological identification is no longer possible (Carreon-Martinez et al. 2011).

Best Wishes,

Shannon

Thank you very much!

Hi Philip

Man I would suggest also genetic barcoding..... if you can amplify cytb or COI, you'll be quite sure of your result as all your mentioned species have these genes sequenced in GenBank.

Hey Hamid,

I am sure it is fairly easy to identify with genetic means, sadly I don't have the possibility to do any Gene work in the Moment. Furthermore it is not that urgent, more out of curiosity as I am studying the food web of a locality with few small pond.

Hi Philip 

I am also working on fish larvae identification as a part of my PhD thesis and have some of your species in my larvae samples. Unfortunately the picture are not really good for this purpose. I do not have an identification key which cover all of these specie but I have some in which you can find at least 5 of them, so I suggest you search on these references.

1-Makeyeva, A.P., Pavlov, D.S AND Pavlov, D.A. 2011. Atlas of larvae and juveniles of freshwater fishes of Russia. Moscow: KMK Scientific Press. 383pp

2-Koblitskaya, A.F. 1981. Key of Fresh-Water Young Fishes. Legkaya i pishchevaya promyshlennost', Moscow, 208 pp

3-Auer, N.A., 1982. Identification of larval fishes of the Great Lake basin with emphasis on the Lake Michigan drainage. University of Michigan-Great Lake Research Division, 776pp. 

4-Mooig, W.M., 1989. A key to the identification of larval bream, Abramis brama, white bream, Beicca bjoerkna, and roach, Rutilus rutilus. Journal of Fish Biology. 34: 111-118.  

P.S: Using morphological characters might not be the best way for larvae identification and I know they change based on larvae size and even environmental factors (for example light intensity and pigments density, size or shape), but it gives you a basic idea. Also, in your case, you do not have high diversity in the pond and it is not necessary to identify it to the lowest taxonomic level (because your object is stomach analysis or maybe determine natural diet), So i think genetic barcoding could be considered in next steps.