Capture of a great Longtail tuna, Thunnus tonggol from off Shore of the city of Salalah, Arabian Sea, Sultanate of Oman in January 2013 is described in this paper. Its morphometric and meristic characters are discussed.

The blueline snapper, Lutjanus coeruleolineatus (Rüppell, 1838), is a significant commercial fish species harvested from the traditional fishery in the Sultanate of Oman. Deficient data on this species, however, make the management strategies challenging, especially in fisheries ecology. A total of 978 specimens were obtained from Dhofar Governorate off the coast of the Arabian Sea during the period between February 2015 and March 2016. In total, 296 sectioned otoliths were analyzed and growth was estimated from non-seasonal growth by using von Bertalanffy method. The parameters of von Bertalanffy growth function, total mortality (Z), natural mortality (M), fishing mortality (F), and exploitation rate (E) were determined and compared with those for Lutjanidae fishes elsewhere. The age structure of male fishes was between 1 and 14 years for males while the age of females ranged from 1 to 18 years. Growth rate (K) was 0.21 y–1 and 0.16 y–1 for males and females, respectively. The hypothetical length of female (L∞ = 46 cm) was relatively higher than that of male (L∞ = 42 cm). The natural mortality (M) was 0.296, total mortality (Z) was 0.372, fishing mortality was 0.076, and exploitation rate (E) was estimated as 0.2. The presently reported study is conducted to examine this fish in relation to growth parameters by analyzing otolith structure. The results of the presently reported study will contribute towards planning the regional fishery management policies in Oman.

Abstract:Improves standard assessments of many commercially valuable fish species as Blue line snapper Lutjanus coeruleolineatus, is considered as an important commercial species harvested in the traditional fishery in the Sultanate of Oman. This will increase our knowledge in fish industry management. The present investigation of some biological aspects of Blue line snapper including male-female sex ratio, condition factor (Kn), gonado somatic index (GSI), length at first maturity for both sexes and developmental stages of ovary. Histological changes during the annual reproductive cycle and the stage of maturity of the ovary of Blue line snapper, L. coeruleolineatus are reported. Random collection of the species (449 males and 529 females) were taken monthly from Dhofar Governorate off the coast of the Arabian Sea at the period from March 2015 to February 2016. The results of this study reported male-female sex ratio was significantly different (P<0.05) from 1:1with dominate of females. The average monthly condition factor (Kn) values showed quite similar trend for both sexes with a slight higher values for females. The gonado somatic indices (GSI) data indicate that L. coeruleolineatus has prolonged breeding season from August to January with two peaks occurring in October and January. The length at first maturity was 28.1 ± 0.0 cm for males and 29.7 ± 0.0 cm for females. In this study five developmental stages of ovary of L. coeruleolineatus are recognized during development. Where GW is the wet gonad weight (g) and TW is the total fish weight (g).The length at first maturity (L m50 ), at which 50% of both sexes were calculated by using logistic equation considered by Froese and Binohlan (2000):Where P is the proportion of mature females or males in each 1-cm length class, L is the mid-class length, L m50 is length at first maturity and a is a constant. Non-linear least-squares fitting with Microsoft Excel Solver problem was used to obtain the best fit of L m50 and a.

Capture of a great Longtail tuna, Thunnus tonggol from off Shore of the city of Salalah, Arabian Sea, Sultanate of Oman in January 2013 is described in this paper. Its morphometric and meristic characters are discussed.

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