الفهرس 
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Abstract
The fishes related to family Mugilidae have economic value as one of the most valuable food resource. Since these catadromous fishes are widely distributed in marine and freshwater area, their cultivation is possible in both marine and freshwater ponds. So more attention must be directed
towards the study of species
habitats.
Three dominant species Liza ramada and Liza aurata)
electrophoreticallY in two freshwater).
of this family in their natural
of Mugilidae (Mugil cephalus. were studied cytogeneticallY and different habitats (marine and
* The cytogenetic studies indicated that, all studied groups have the same chromosome number (2n = 48). In case of Mugil cephalus, all chromosomes are acrocentric, while in Liza ramada or Liza aurata, 23 pairs are acrocentric and the last
pair was subtelocenteric.
The comparison between mean lengths of haploid set of chromosomes of all studied groups illustrated that :
* In marine habitat there was variation in all chromosomes between Mugil cephalus and Liza ramada except the last pair. But there was a highly significant difference between the chromosomal mean length of Mugil cephalus and Liza aurata.
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* In freshwater area the variation was clear between the chromosomal mean length of both Mugil cephalus and Liza ramada.
*There was a clear environmental effect on Liza ramada where large variation was illustrated between marine and freshwater species, but this variation was decreased in case of Mugil
cephalus.
*Chromosomal length variation was obvious between the different studied species in the different habitats.
*Serum proteins electrophoretic studies revealed that the proteinograms of the studied species have eleven fractions except that of females Liza aurata and juveniles of freshwater Mugil cephalus (10), males of Liza aurata and juveniles of marine Liza ramada (9), but the proteinogram of marine Mugil cephalus juveniles have only 7 fractions. * The complete disappearance of fraction number 9 in all juvenile groups of both Mugil cephalus and Liza ramada can be used to differentiate juveniles from adults (males or females in which the fraction was appeared) by looking at their proteinograms. The same case was observed in fractions number 1,2 and 6 to differentiate between males and females of Liza
aurata.
* The absolute appearance of fraction 4 was characteristic for the studied Mugilidae species.
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*The higher protein content (relative area percentage of fraction) was observed in fraction number 5 for all groups except marine males of Mugil cephalus (4), both males and juveniles of freshwater Mugil cephalus (3) and marine juveniles of Mugil cephalus (10).
*The comparison of serum proteinograms between species indicated that there was similarity between males or females of marine Mugil cephalus and Liza ramada. But, lower similarity was observed between Mugil cephalus and Liza aurata in either their males or their females and this was supported by the cytogenetic results.
*On the other hand, similarity was pronounced between the females of Liza ramada and those of Liza aurata. However this similarity was decreased between males of the both species.
*In freshwater habitat the similarity coefficient of serum proteinograms was higher between females of Mugil cephalus and those of Liza ramada, but this was low between males of
the same two species.
•The higher variation of serum proteinograms between
juveniles of marine Mugil cephalus and those of Liza ramada was in accordance with the results obtained from cytogenetics
study for the two species.
* In the term of sex comparisons in serum proteinograms, similarity was clear between adults of both sexes in case of Mugil cephalus and Liza ramada in all the studied habitats
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except freshwater males and females of Mugil cephalus and also those in case of marine Liza aurata.
*On the other hand, the variation was obvious between serum protein patterns of juveniles and adults (males or females) of both Mugil cephalus and Liza ramada, this as a result of the effect of growth and sexual maturity.
*There was a clear environmental effects on the patterns of serum protein of juveniles, males of Mugil cephalus and females of Liza ramada. But in case of females of Mugil cephalus and males of Liza ramada, this effect was small.
*The results of electrophoresis for sarcoplasmic proteins of the studied groups indicated that the proteinograms of all groups have ten fractions (9 major fractions and the last fraction distinguished by two minor fractions (10A & 10B) except males of freshwater Mugil cephalus , juveniles of marine Mugil cephalus and females of Liza aurata in which they showed only 9 fractions.
*The absolute appearances of fractions number 2 and 4 are characteristic for all the studied species.
•The higher protein content was restricted in fraction
number 4 for all the studied groups except males of Liza aurata (5).
*The studies of similarity of sarcoplasmic proteinograms between different species illustrated that, in marine
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habitat, the similarity was high between the males and the females either in Mugil cephalus or Liza ramada. The similarity was rather low in case of males or females of Mugil cephalus and Liza claret’s and this agreed with the results of both cytogenetic and serum proteins. But in case of Liza ramada and Liza aurata, the similarity was obvious between females than males.
* In freshwater habitat the variation in sarcoplasmic protein spectrum was higher between Mugil cephalus and Liza ramada (either in males or females) Also the variation was observed between marine juveniles of Mugil cephalus and those of Liza ramada, this also agreed with the results obtained from cytogenetic and serum proteins studies.
* The results of sex comparisons were in agreement with that of serum proteins.
The habitat affects clearly on the similarity of sarcoplasmic proteinograms in case of juveniles, males and females of Mugil cephalus and this is in agreement with the results obtained from serum proteins study. But in case of Liza ramada no environmental effect was noticed on the similarity especially in females (SC = 1.0 ) than males (sC = 0.73).