Population Dynamics and Management of White Shrimp Metapenaeus Stebbingi (Penaeidae) at Lake Timsah, Suez Canal, Egypt

Studies were conducted on the dynamics of the exploited population of white shrimp Metapenaeus stebbingi Nobili 1904 at Lake Timsah (Suez Canal, Egypt). Growth parameters were determined using the length frequency distribution over a 13-month period. The asymptotic total length was estimated as 14.84, 16.95 and 17.07 cm for males, females and sexes combined, respectively. The growth parameter K was 2.63, 2.16 and 2.10 yr^-1 for males, females and sexes combined, respectively. The longevity was 9 months for males and 12 months for females. The instantaneous rate of total mortality was estimated at 10.75, 7.9 and 9.1 yr^-1 for males, females and sexes combined, respectively, while natural mortality was 3.73 yr^-1 for males, 3.16 yr^-1 for females and 3.09 yr^-1 for sexes combined. Hence, the fishing mortality was calculated at 7.02, 4.74 and 6.01 yr^-1 for males, females and sexes combined respectively. The current rate of exploitation E was given as 0.65 for males, 0.60 for females and 0.66 for sexes combined, indicating that the stock of white shrimp is overfished. Relative yield per recruit and relative biomass per recruit analysis for sexes combined showed that M. stebbingi stock at Lake Timsah is in a situation of overfishing and the present level of exploitation rate should be reduced by about 46% to maintain a sufficient spawning biomass.