Length-Weight relationships, Mortality and Relative Yield Per Recruit of Common Pandora, Pagellus erythrinus from the Mediterranean Coast, North Sinai, Egypt

Due to the importance of fish biological measurements in managing fisheries along the Mediterranean coast of Sinai, this study was conducted on common pandora, Pagellus erythrinus, during the 2021 fishing season. Data were collected monthly from January to December 2021, comprising a total of 1,512 fish samples from commercial catches. The fish ranged in length from 11 to 27.9cm and in weight from 17.7 to 235.4g. The most important measurements include the length-weight relationship of P. erythrinus, described by the power equation: W = 0.0106L³.0416 for combined sexes. The study identified four age groups, with the lengths at the end of each year being 15.84, 20.3, 23.5, and 25.5cm for the 1st, 2nd, 3rd, and 4th years of life, respectively. The estimated von Bertalanffy growth parameters were L∞ = 29.98cm and k = 0.38 year⁻¹. The growth performance index (Φ′) was 2.538. The estimated length at first capture was 16.79 cm. The total, natural, and fishing mortalities were 1.92, 0.58, and 1.34 year⁻¹, respectively, for both sexes combined. The exploitation ratio was E = 0.70, indicating a high level of exploitation of P. erythrinus. The relative yield per recruit analysis (Y'/R) showed that the current exploitation level significantly exceeds the sustainable threshold (E₀.₅ = 0.381). To sustainably manage this resource, the current exploitation rate needs to be reduced by 45%, from 0.70 to 0.381.