Length-weight relationships of thirteen species of parrotfish (Family scaridae) inhabiting the egyptian coasts of the red sea.

Abstract

Length-weight data of population are basic parameters for any monitoring study of fishes since it provides important information about the structure of the populations. Also, it is important for fish stock assessment essential for estimating growth rates, age structure, calculate the standing stocks biomass, condition indices and several other aspects of fish population dynamics. Therefore, we investigated the length-weight relationships of 13 parrotfish species (Family Scaridae) collected seasonally from the Egyptian Red Sea coast during 2014/2016. The" b "values of the length-weight relationships ranged from 2.17 to 3.88 with a mean value of 2.729±0.0788 (S.E.) for the studied species. Chlorurus geuozonatus showed a positive allometric growth while Calotomus viridescens; Cetoscarus bicolor; Chlorurus sordidus; Chlorurus gibbus; Hipposcarus harid; Scarus frenatus; Scarus ferrugineus; Scarus fuscopurpuerus; Scarus ghobban; scarus niger and Scarus psittacus were show a negative allometric growth. Isometric growth was represented by two species Hipposcarus harid and Scarus colon. 98% of the studied species had "R²" values higher than 0.90, which indicated the increase in length will contribute with increase in weight. These results are useful references for the management plan.