The sagittae mass asymmetry was studied in the teleost Lutjanus bengalensis and it is calculated as the difference between the mass of the right and left paired otoliths divided by average otolith mass. As in the case of other symmetrical fish species, the result of the present study showed that the absolute value of sagittae mass asymmetry (X) in L. bengalensis does not depend on fish length and otolith growth rate. On the other hand, the absolute value of otolith mass asymmetry is increased with the fish length. The value of sagittae mass asymmetry falls between -0.2 and +0.2. Özet: Umman Denizi, Muscat Şehrinde Lutjanus Bengalensis (Family: Lutjanidae) Otolit Kütle Asimetrisi Üzerine Bir çalışmaBu çalışmada; teleost Lutjanus bengalensis'in kütle asimetrisi, sağ ve sol otolit çiftlerinin kütleleri, ortalama otolit kütlesine bölümü ile hesaplanarak çalışılmıştır. Diğer simetrik balık türlerinde olduğu gibi, bu çalışmada da sagittae kütle asimetrisinin mutlak değeri (X)'nin L. Bengalensis türünde de balığın boyuna ve otolit büyüme oranına bağlı olmadığı görülmüştür. Diğer yandan mutlak otolit kütle asimetrisinin boy uzadıkça artmıştır. Sagittae kütle asimetri değeri -0.2 ile +02 arasında hesaplanmıştır.

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Background. Shrimps are one of the most valuable marine resources of Oman and shrimp fi sheries is greatly contributing to the national economy, and sustainability of traditional fi sheries villages. However, the shrimp trawl fi shery has one of the highest bycatch rate of any fi shery and cause negative impacts to marine populations and benthic habitats. This study provides the fi rst data on the c omposition and abundance of the bycatch in the main shrimp fi shing grounds distributed along the south-eastern coastline of Oman in the Arabian Sea. Materials and methods. Shrimp trawl survey was conducted monthly from January to December 2013 in seven sites using demersal otter trawl. Overall, 93 trawl catches were used for the analysis of the bycatch composition based on weight, number, and frequency of occurrence. Top ten species and top fi sh families, cephalopods, and crabs were defi ned in the bycatch. The bycatch compositions were compared in different regions using biodiversity indices and the cluster analysis. , in different months with an overall mean (±SE) of 58.7 ± 5.2 kg · h -1 (n = 93). The bycatch to catch ratio was estimated 8.9 : 1 for shrimp fi sheries. This ratio fl uctuated signifi cantly over the year with minimum values from April to September. The bycatch composition included 97 bony fi sh species from 36 families, 12 species from 7 elasmobranchs families and several species of cephalopods and crabs. Catfi shes (Ariidae), frogfi sh (Antennariidae), ponyfi shes (Leiognathidae), and rays (Dasyatidae and Gymnuridae), represented a majority of the bycatch. Conclusion. Shrimp fi shery in Oman is affecting mainly small-sized and slow-moving fi shes, and invertebrates with low economic value. However, the fi ne-meshed shrimp trawls also capture juveniles of commercial important fi shes and cause some ecological problems. The results from the study point out the necessity of management actions to develop a special policy on bycatch reduction in Oman fi sheries.

Cases of partial hyper pigmentation and malpigmentation were reported from Diagramma pictum and Pardachirus marmoratus collected from the Arabian Sea coasts of Oman. These cases are the first report on color anomalies in these two fish species. Hyper pigmentation spots were observed mainly on the side of D. pictus, while the malpigmentation patch was observed across the body of P. marmoratus. Both cases are not pathological, but they have an economic effects that the melanic or the ambicolored specimens may cause to the fishermen due to being unfavourable by the customers.