The Length-Weight Relationship and Condition Factors of Twelve Fish Species, with Special Reference to Cichlid species from the Mediterranean Manzala Lagoon, Egypt

Abstract




The length-weight relationship of fish is one of the most studied biological characteristics of fish biology. The relationship between the length and weight of fish species can provide additional insights into its morphology, life history, environmental conditions, growth pattern, and general health. In the current study, the length-weight relationship and condition factors of 12 different fish species were assessed mainly during dredging operations in Manzala Lagoon. In addition, the length distribution was analyzed for cichlid species. A total of 6375 samples of fish species were collected between November 2019 and October 2021 from several sites covering the lagoon's water body using different fishing gear and methods. The studied species were found to belong to six families, namely Cichlidae, Clariidae,Bagridae, Mugilidae, Moronidae, and Anguillidae. The results of the present study recorded that half of the species had isometric growth, and the other half showed allometric growth. The (b) values of pooled data obtained from the twelve species ranged from 2.83 to 3.34. The findings of this study showed that the condition factor (K) of the studied fish was in good condition except for A. anguilla, C. gariepinus, C. auratus, and B. bayad (0.2199, 0.7287, 0.8109, and 0.8306, respectively). A. anguilla (0.2199) had the lowest condition factor, while C. zillii (1.901) recorded the highest. The values of both parameters (b and K) indicate the good well-being of fish in the lagoon. Intensive studies are recommended on Manzala Lagoon after the completion of the dredging operations. The data provided in the current study can be utilized as a basis for the effective management of these species' fishery in Manzala Lagoon.