دراسة مقارنة لحساب المساحة التنفسية و نسب العضلات الحمر والبيض في أسماك الشانك Acanthopagrus arabicus (Iwatsuki,2013) والشلك Leuciscus vorax (Heckel , 1843) والبلطي الزيلي Coptodon zillii(Gervais,1848) في محافظة كربلاء المقدسة

A comparative study to calculate the respiratory area and the proportions of red and white muscles in Acanthopagrus arabicus(Iwatsuki, 2013), Leuciscus vorax(Heckel, 1843) and Coptodon zillii (Gervais,1848) )in Holly Karbala City

Summary
The current study dealt with three species of local bony fish (Teleost), belonging to different families, namely: Coptodon zillii (Gervais, 1848) belonging to the family Cichlidae, Acanthopagrus arabicus (Iwatsuki, 2013) belonging to the family Sparidae and Leuciscus vorax (Heckel, 1843), which belongs to the family Cyprinidae, fish samples of the study were collected from the Shatt alHindi (Euphrates River) in the Holy Karbala, and the study was conducted from the beginning of September 2020 to the end of December 2020, in which ( 50 samples for each of the three studied species were distributed to different lengths groups ,their lengths ranged between (100-300 mm) and weights between (66.41-359.29 g), and the current study designed to be a comparative study of some aspects related to the locomotor activity of fish, which include : calculating the respiratory surface area of the totall and relative gills, The proportions
of red and white muscles from two different body regions in the three studied species. The results of the current study for the calculation of the gills surface area indicated that the average factor of the total length of the gill filament (mm) had a direct effect on the values of the totall gill respiratory area, and when studying the correlation coefficient between the average length of the gill filaments and the average length of the fish, a positive direct correlation was observed. Between them, their rates were (0.97, 0.95 ,0.97) in the C. zillii, A. arabicus and L. vorax respectively, were considered among the medium-active fish , and that is depending on the average of the total length of the gill filament and its apparent effect on the values of the respiratory area of the gills. The results of the current study revealed the difference of the three studied fish species with the average of the totall respiratory area and the relative (mm / g) of the gill for the groups of length studied within one species and for the three studied species(11079.59, 12585.82 , 12998.67 mm) in the C. zillii, A. arabicus and L. vorax respectively, and it was observed that there was a direct correlation between the average of the totall respiratory area (mm2) and the mean of the total length of the studied fish it was ranged(0.97, 0.98 ,0.96 ) in the C. zillii, A. arabicus and L.vorax respectively. The relative respiratory area (mm 2/ g), its average ranged between (80.31, 87.03, 89.02 mm 2 / g)in the C. zillii, the A. arabicus and the L. vorax, respectively, The results of the correlation relationship between the average of the relative respiratory area (mm 2/ g) of the gills and the average length of the total fish noted the existence of a negative correlation between them it was ranged (-0.97, -0.97 ,-0.95) in the C. zillii, A.arabicus and L. vorax respectively .The results of the statistical analysis for calculating the average of the total respiratory area (mm2) and relative (mm2 / g) and the presence of significant differences (p<0.05) between the three studied fish species. L vorax surpassed on the A. arabicus and C. zillii, and the A.arabicus surpassed on the C. zillii fish. The results of the study indicated that the percentage of red muscles were much less, than the percentage of white muscles in different areas of the body (R2, R1) and the length groups studied within the same species and for the three species studied. the rates of Red muscle proportions for the anterior (R1) and posterior body regions (R2) ranged between (2.89 – 8.65%) in the C. zillii, A. arabicus and L.vorax respectively, while the average of white muscle proportions for the anterior (R1) and posterior body regions (R2) ranged between (8.76 – 97.23%) in the C. zillii, A. arabicus and L. vorax respectively, and theresults revealed that the proportions of the red muscles increase towardsthe posterior region (caudal peduncle) of the body of the fish, and this reflects the importance of this area in the movement and swimming offish, in contrast to the proportions of white muscles that were reducedas we went towards the posterior region (caudaLe peduncle). The results of the study of the total rates of red and white muscle proportions and the studied length groups showed clear differences within the studied length groups for the three species studied. The total averages of red muscle proportions ranged between (5.49, 5.83, 6.25%) in the C. zillii, A. arabicus and L. vorax respectively, while the rates
were Total white muscle proportions (92.72, 92.53, 93.51%) in the C.ةzillii, A. arabicus and L. vorax respectively, and the results of theةstatistical analysis showed a strong positive correlation between the total rates of red muscle proportions and the average length of fish, astheir averages ranged between (0.95, 0.98, 0.93). in the C. zillii, A.arabicus and L. vorax respectively.While the correlation was inversely related between the averages of white muscle proportions and the average length of fish, as it ranged between (-0.95, -0.98, -0.92) in the C. zillii, A. arabicus and L. vorax respectively, and the results of the statistical analysis for calculating the total rates of red and white muscle proportions indicated that there were no significant differences (p<0.05) among the three fish species studied, and in based on the results of the study, the in the C.zillii, A. arabicus and L. vorax were considered among the Sprinters fishes, depending on the proportions of the red and white muscles in their muscle tissue.