BIOLOGICAL STUDIES ON THE NARROW-BARRED SPANISH MACKEREL, SCOMBEROMORUS COMMERSON OF EASTERN MEDITERRANEAN (NORTH SINAI COAST) EGYPT DURING 2017
Mohsen, S.H.1; EL-Aiatt A.A.O.2;
Ahmed M.Z.1 and Ahmed A.A.1
1Faculty of Agriculture, Al-Azhar University.
2National Institute of Oceanography and Fisheries NIOF.
| Received 2 /1 /2020 |
Accepted 16 /1 /2020 |
ABSTRACT
The goal of the present study is to give basic information required for managing Narrow-barred Spanish mackerel, Scomberomorus commerson (Lacepéde, 1800) of Eastern Mediterranean (North Sinai Coast) Egypt. 1189 Samples of S. commerson (12.0 to 137 cm total Length and 12.2 to 14880 g. total weight), were collected during 2017. The relationship between length and weight was W= 0.0111L 2.8469. Age was determined by otolith where age groups 1 to 5 years. Growths in length and weight at the end of each year were calculated as 36.49, 62.41, 86.15, 101.5 and 114.35 cm for the 1st, 2nd, 3rd, 4th and 5th year of life respectively. The growth parameters of von Bertalanffy equation were calculated as (L∞= 161.67 cm, K = 0.2436 year-1 and t0 = -0.0501 year-1). Growth performance index (φ′ = 3.78). Mortality rates were 0.9536 yr−1, 0.3854 yr−1 and 0.5682 yr−1 for total, natural and fishing mortality respectively. The exploitation rate E = 0.60. The length and age at first capture (Lc ) (Tc ) was 34.5 cm and 0.9353 year respectively.
In the end, 67.5% of the total fish catch (0 and 1st, 67.5% of age groups) of Scomberomoruscommerson is small and this affects the fish stocks of these fish and must be stopped to prevent growth overfishing and exploitation of large size fish (2nd age, and 3rdof age groups) must be regulated to prevent recruitment overfishing. Also the exploitation rate (E) is 6 and is a high rate is high. Therefore, should be reduce the fishing effortto preserve the fish stocks from these fish, or at least should not be increaseing the fishing effort, as we are in the stage of low Yield per recruit also these fish are important in north Sinai as the catch from these fish reached 90 tons per year and their prices are affordable.
