ESTIMATING SOME BIOLOGICAL PARAMETERS AND YIELD PER RECRUIT FOR FISHERY MANAGEMENT OF SPOTTED SEA BASS Dicentrarchus punctatus IN BARDAWIL LAGOON EGYPT

Document Type : Researches

Authors

1 Dept. Fish Res. and Aquacul., Fac. Environ. Agric. Sci., Arish Univ., Egypt.

2 Fac. Aquacul. and Marine Fisheries, Arish Univ., Egypt.

Abstract

The present study aimed to assess some biological parameters and yield per recruit for fishery management of spotted sea bass Dicentrarchus punctatus in Bardawil lagoon, Egypt. For this purpose, 3286 specimens of D. punctatus were collected during two fishing seasons between January 2020 and December 2021. The total length (TL)of the samples ranged from 10.1 to 34.7 cm, and the weights ranged from 9 to 368.4 g. The maximum life span was five years length range of 12.3 – 28.29 cm TL. The parameters of the von Bertalanffy growth function were K = 0.2371 year-1, L∞ = 37.36 cm and t0 = -0.7505 years-1 during 2020-2021. The rates of total mortality (Z), natural mortality (M) and fishing mortality (F) were 0.9107, 0.3121 and 0.5986 year-1 during the period of study.  Exploitation rate E was 0.66 indicating that the population of this species is being heavily exploited. The estimated total length at first capture Lc was 17.6 cm during both 2020 and 2021. When the fishing effort is stable at 0.5986, the yield per recruit was 44.2 at the length at first capture 17.6 cm and the age at first 1.94 years. With increasing   the length at first capture until 22.0 cm, the yield per recruit was reached 47.6. Any increase in the length of the fish, a decrease in the yield per recruit.  To manage the spotted sea bass Dicentrarchus punctatus biologically, should be decrease value of exploitation rate by increasing of the length at first capture (>17.6 cm). or decreasing of fishing effort.

Keywords

Main Subjects