BIOLOGY AND FISHERIES MANAGEMENT OF RABBITFISH, Siganus rivulatus
IN BARDWIL LAGOON, EGYPT
Mohamed salem1 and Attia El_Aiatt2
Faculty of Environmental Agriculture Sciences, Arish – University
National Institute of Oceanography and Fisheries NIOF
|Received 20/ 9/ 2017||
Accepted 13/ 11/ 2017
Rabbitfish, Siganus rivulatus in Bardawill lagoon has considerable commercial important species. This study aims to identify some of the biological properties of this species and supply management catches this information to preserve this kind of fish. Length-based methods were used to study the growth of the rabbit fish Siganus rivulatus, in Bardawill lagoon. Samples (ranged from 7 to 21.6cm total length and 4 to 116g total weight) were collected from April to December 2016. Age was determined from otoliths measurements and the results showed that the maximum life span is 5 years. Back calculation length at the end of each year were calculated as 10.19, 13.51, 16.59, 18.02 and 19.49 cm. Total length- weight relationship was estimated as w=0.0152L 2.8406. Length at first capture Lc was 13.5 cm and age at first capture was 1.99717years. Size group 13-13.9 cm (about 19.5% of the total frequencies), is the domination in the size groups. Growth parameters were L∞ = 23.09 cm, K = 0.3191 y-1 and t0 = – 0.7571 y-1. The growth performance index was 2.23. The instantaneous total, natural and fishing mortality are 0.9684, 0.4495 and 0.5189 year-1 respectively. Exploitation rate (E) was 0.54 year-1. The results indicated that the S. rivulatus resource in Bardawill lagoon is moderate exploited but the juvenile was dominated in landing. The higher values of yield per recruit (10.28, 10.75, 11.47, 11.7014 and 11.849) were with Tc = 1.25, 1.5, 1.99717, 2.25 and 2.5 years at fishing mortality 0.9, 1.2, 2.1, 3.2 and 6 respectively. All indications are that mesh sizes needs to be increases or must be fished by the legal trammel nets only.