seyyed yousef paighambari

Previous studies of the relative abundance of cephalopods in the Gulf of Oman are limited, and they focused on the commercial species Sepia pharaonis. Therefore, the relative abundance of some cephalopods in the Northeast Gulf of Oman (neritic zone) was studied based on the Catch Per Unit of Effort index. Commercial fisheries data were collected using field sampling by a stern trawler with a bottom trawl gear (cod-end mesh size: 85 mm) from the Ferdows fishing fleet. The possible effects of five variables depth, distance from the shoreline, fishing time of day, the velocity of the vessel, and type of haul on Catch Per Unit of Effort were measured with Generalized Linear Models, Zero-Inflated Models, and Redundancy Analysis (both regression and ordination analyses). Sepia pharaonis and Uroteuthis (Photololigo) duvaucelii had the highest relative abundance based on weight and number, respectively. Weight-based relative abundance of Sepia pharaonis was 5251.126 gr/hour (S.E. ± 1156.672), while the number-based relative abundance of Uroteuthis (Photololigo) duvaucelii was 56.201 individual/hour (S.E. ± 8.560). Overall, Sepia pharaonis, Uroteuthis (Photololigo) duvaucelii, and Sepia stellifera had the highest relative abundance values based on weight. Also, Uroteuthis (Photololigo) duvaucelii, Sepia stellifera, and Sepia omani had the highest relative abundance values based on the number. According to the uneven topography of the study area, both in regression and ordination analyses, the depth variable had the greatest effect on the relative abundance of cephalopods. The effect of depth was more noticeable in ordination analyses (often p < 0.001).

This study estimated the discarded catch of the Moshta gear and the length at maturity parameter (Lm50) of two species of discard aquatics Arius maculatus and Plicofollis dussumieri. Sampling carried out in the city of Bandar Abbas since December 2014 for one year. After specifying the maturity of samples by the Biswas (1993) method, to calculate the length at maturity the least-squares technique under the king (2007) method was performed in Data Analysis Solver of Excel 2013. Discard catch included 65.23% of the weight and 74.93% of the number while commercial catch included 34.77% of the weight and 25.07% of the number. According to the results, the length at maturity of Arius maculatus was 28.2 cm, 51.50% were below puberty. The length at maturity of Plicofollis dussumieri was 32 cm, 62.3% were below puberty. The results of this study showed that Moshta with a high diversity of trapped aquatics, while some of these aquatics are caught immature, was a threat to fisheries stocks in Hormozgan province and the Iranian waters of the Persian Gulf.

This study aimed to find new species of cephalopods in the Iranian waters of the Gulf of Oman. Two species of Oegopsida (Abralia steindachneri Weindl, 1912 and Joubiniteuthis portieri (Joubin, 1916)) and also one species of Sepiida (Sepia omani Adam & Rees, 1966) were identified. Samples were collected in March and April 2019, using a Myctophidae trawler. To capture A. steindachneri a two-panel bottom trawl (codend mesh size (A) equal to 60 mm) was used, while for J. portieri and S. omani a four-panel midwater rope trawl (codend mesh size (A) equal to 90 mm) was applied. Taxonomic studied on these rare cephalopods, in this region, would be helpful for protecting their stocks as well as safely exploitation them.

This investigation was conducted in Doroudzan Dam located in Fars province from winter 2017 to summer 2018. The fish specimens were caught using monofilament gillnet with 20, 70, 100 and 120 mm mesh sizes. Overall, 283 fish specimens belong to the Cyprinidae (7 species) and Mugilidae families (1 species) were caught which were included: Cyprinus carpio, Carassius gibelio, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, Alburnus mossulensis, Capoeta damascina, Carasobarbus luteus and Planiliza abu. C. carpio and P. abu were dominant species during sampling seasons.The highest range of total length and weight belonged to H. nobilis (Length range: 52.8-102.6 cm; Weight range: 2811.5-20628.9 g) and the lowest ranges belonged to A. mossulensis (Length range: 8.6-15.1 cm; Weight range: 5.05-29.4 g) and P. abu (Length range: 8.3-19.6 cm; Weight range: 4.52-59.48 g). The highest amounts of the Shannon-Wiener and Simpson indices were observed in spring (2.413) and winter (0.795), respectively. PCA result showed that C. carpio and P. abu were the most effective species that caused the changes in the seasonal fish abundance and diversity. Also, the most amounts of seasonal similarity were between summer and spring (J= 0.625; S= 0.729) and the lowest amounts were between summer and winter (J= 0.375; S= 0.545).

In this study the effects of two catch methods (gillnet and beachseine) were investigated on some spermatological parameters of Kutum brood stock. For this purpose 8 adult male caught by gill net and beach seine were stripped by applying slight pressure to abdomen section of fishes and sperm samples were transferred to laboratory in ice box for spermatology analysis. Semen volume was measured by scaled syringes and sperm movement duration by faze-contrast microscope. spermatocrit was determined by haematocrit reader. The results showed significant (P <0.05) differences in spermatocrit levels between fishes that were captured by gillnet and beach seine, but no significant (P >0.05) differences observed in semen volume and sperm movement duration between the two methods. The results showed that fishes captured by gillnet had more positive index in comparison to fishes captured by beach seine.