Dear colleague,

Most teleosts are not sexually dimorphic so that it is very difficult or almost impossible, without dissection, to determine whether the individual is a male or female based on observation of external features. Thus, my suggestion is that you dissect the specimens under study and separate them by identification of ovaries or testes. In parallel, search if you are able to match any special external morphology with one sex or another. This is not difficult for adults, especially when they are in their reproductive periods, but it can be a difficult work when dealing with juveniles or subadults.

With my best wishes,

Gloria

I agree with the colleague Gloria. There are no external features distinguishable for the sexes in Mugiliadae in general. Dissection is the only method and this also works for stage 2 of gonad maturation and higher. In totally immature fish, the gonads are just thin threads and then you need histology for being sure. Unfortunately this is the case.

Happy summer

G. N. Hotos 

.... in mature stages of mullets, sex can be easy determined by the gonad secretion colour and formed after pressure at the abdominal part of the fish: yellow-orange with visible eggs for females and white milky sperm for males.

regards

GK

Dear Colleague George,

Yes, it is easy for almost all fish species to classify an individual is a male or a female when they are in their reproductive period. But it is not the case when someone wants to identify them when they are not in their reproductive period!  I believe that Wualid's question concerns fishes outside of their reproductive period, and probably, also includes sexual identification of subadults.

Regards,

Gloria

Dear Colleague Gloria

I agree with you... out of the reproductive period the identification is problem.. (I was noted: in mature stages...). However, the above method works (I did test) and in premature stages (III and IV mature stage by Kesteven) but needs more pressure at the abdominal part of the fish. In all cases it works during and before to reproductive period and only for the spawning stock.

Regards,

GK

Dear all,

for sure, dissection will bring a final result for this! But, as everyone knows it is an invasive and destructive method. Testing if echographia could be applied here could be interesting. At least, it will preserve animals.

This technique may provide results for mature animals, but for juveniles and immatures, I guess that dissection remains the sole applicable method.

Hi Walid

I agree with Geroge and Gloria. I worked on those species and the only way to separate individuals according to sex is dissection. However, during the spawning season, a slight pressure on the abdominal part towards the genital opening will make sense.