دراسة المساحة التنفسية ونسب العضلات الحمر والبيض في سمكتي الكارب العشبي1844 Ctenopharyngodon idella Val. والفضي Hypophthalmichthys molitrix Val. 1844 في مواقع مختلفة من نهر الهندية في محافظة كربلاء المقدسة

Ctenopharyngodon idella Val. Hypophthalmichthys molitrix Val. 1844 In different locations of the Hindiya River in the Holy Province of Karbala

This study was conducted on two species of bony fish that live in freshwater, belonging to the family Cyprinidae They are: Ctenopharyngodon idella (Valeneciennes,1844) and Hypophthalmichthys molitrix (Valeneciennes, 1844) (50) fish were collected, each with five groups of different lengths. Their average lengths ranged from (325.13 – 485.16) mm in grass carp and ranged between (329.21 – 482.47) mm in silver carp, during the period from November 2023 to the end of January. 2024, using a gill net (tunnel) with circles of different diameters. A comparative study was conducted to calculate the respiratory area and muscle ratios of both types, red and white. It is one of the studies that is related to some aspects related to fish movement activity, represented by calculating the gill surface area and calculating the muscle ratios in different areas of the body, namely: (R1) the area behind the head, (R2) the area in front of the tail area.
The results of the study related to measuring the components of the absolute gill area, which included: the average total length of the gill filaments, the number of secondary gill plates per millimeter, and the area of one gill plate (mm2), showed a direct effect of the average total length of the gill filament on the average gill surface area, and by studying the correlation relationship (r) Between the average total length of the fish and the average total length of the gill strand, it was found to be a direct relationship. The value of the correlation coefficient ranged from (0.994, 0.998), while the correlation relationship was inverse between the average total length of the fish and the average number of secondary gill plates. The value of the correlation coefficient ranged in it. (-0.983, -0.961), while the correlation relationship was direct between the average total length of the fish and the area of the secondary gill plate. The value of the correlation coefficient ranged from (0.999, 0.999), while the correlation relationship was direct between the length of the fish and the average absolute gill area. The value of the correlation coefficient ranged. It contains (0.993, 0.984, 0.9915) in grass and silver carp.
The results of the study related to calculating the relative gill area (mm2/g) showed a clear difference between the two species. Its value in grass carp was (40.27 mm2/g), while its value in silver carp was (40.92). By studying the correlation relationship, it was inverse between the average total length For thickness and relative gill area average, the value of the correlation coefficient ranged from (-0.928, -0.959), and it was noted when statistically analyzing the results to determine the differences recorded by calculating the average total length of the gill filaments, the number of secondary gill plates in one millimeter, the area of one gill plate, the absolute gill area, There were significant differences (p≤0.05), while in relative gill area there were non-significant differences (p≥0.05) in grass and silver carp.
Grass carp and silver carp were considered active fish based on their average total length of gill filament.
The results of the study showed a clear difference in the average proportions of red and white muscles depending on the body region studied and the length group studied. The rates of red muscle proportions increased with the increase in the average total length of the fish as we moved towards the caudal region of the body. This was proven by the study of the direct correlation relationship, in which the value of the correlation coefficient ranged (0.991). 0.993, and the rates of total red muscle percentages in grass carp ranged between (12.34-20.18%), and in silver carp ranged between (14.43-22.18%), while the rates of total white muscle percentages in grass carp ranged between (87.31). – 79.60%), and in silver carp it ranged between (85.50 – 77.49%). Therefore, it is clear that the rates of white muscle percentages decrease with the increase in the average total length of the fish as we move towards the caudal region of the body. This is what was proven by the study of the inverse correlation relationship, in which the value of the correlation coefficient ranged. (-0.995, -0.988), and when statistically analyzing the results to determine the differences recorded by calculating the overall rates of the proportions of red and white muscles, as well as their rates within the studied body regions, it was observed that there were significant differences (p≤0.05) in grass and silver carp.
Grass carp and silver carp are considered resilient fish; Because it contains high rates of red muscles, it swims in a slow, continuous, and long manner.