The reproductive cycle the tiger tooth croaker (Otolithes ruber) were studied from a total of 540 specimens of tiger tooth croaker collected in Hormuzgan waters between September 2007 and desember 2008. Weight-length relationships for tigertooth croaker was W=0.0064L3/1268. Lm50 for tigertooth croaker was 33.7cm. Sex ratio (femail: male) for tiger tooth croaker 1.76:1. Maximum absolute and relative fecundity for tiger tooth croaker were 1128401 and 943.7 respectively. Maximum diameter of ovol for tiger tooth croaker and was 350 micron. Spawning seasons tiger tooth croaker obtained between May and June.

This study was conducted to estimating the amount of non-standard sizes (with lengths less than LM50) fishes of shrimp trawls in the Hormozgan Province coastal water during shrimp fishing season Sampling was carried out using the Tabas otriger commercial trawler during 55 hauls. Eight commercially valuable species including Pampus argenteus, Parastromateus niger, Plicofollis dussumieri, Saurida tumbil, Nemipterus japonicus, Scomberomorus guttatus, Platycephus indicus and Otolithes ruberwere were investigated in this study. S. guttatus (94.33%), P. argenteus (93.19%), O. ruber (91.57%), P. niger (89.86%), P. indicus (66.66%), S. tumbil (60.4%), N. japonicas (35.38%) and P. dussumieri (4.42%) had most high non-standard length in catch, respectively. LOPT were calculating for P. dussumieri. The results showed a high pressure on the species of the shrimp trawl that can be the reason of species composition change in the Persian Gulf fisheries.

The reproductive cycle the Bigeye scad (Selar crumenophthalmus) were studied from a total of 340 specimens of Bigeye scad collected in Hormuzgan waters between September 2011 and August 2012. Weight-length relationships for Bigeye scad was W = 0.032L 2.8352 Lm50 for Bigeye scad was 19 cm. Studies show that due to the length and weight of the fish is an isometric growth. Sex ratio (femail: male) for Bigeye scad 1.05:1. Maximum absolute and relative fecundity for Bigeye scad were 102841 and 581.02 respectively. Spawning seasons Bigeye scad obtained between Feb and jun. It is best to catch this species in spawning season to be prevented

The spawning season, fecundity and Lm50% of the Caspian Sea prawn (Palaemon adspersus) were investigated in the coastal waters of Guilan province. A monthly sampling was conducted using a bottom trawl with mesh size 3 mm in cod end in areas 0-5 and 5-10 meters deep during the year 2002.Mean total length, carapace length and weight of ovigerous female of Palaemon adspersus were 51.95±3.1mm, 13.95±1.9 mm and 2.742±0.58g (X±S.D). Minimum and maximum total length of ovigerous specimens were 37 and 59.3mm with a weight 1.002 and 4.145 grams respectively. We found that the spawning season of Palaemon adspersus begins in April and ends in September with a peak in June. Mean fecundity of the species was 1994.5±506.6. The size at which 50% of females are mature was estimated to be 51.27mm total length.

The oriental river prawn (Macrobranchium nipponense) is a commercially important farmed species in some countries of Southeast Asia, and an exotic one distributing in lakes, reservoirs and aquaculture ponds in the northern provinces of Iran. This study was conducted to investigate the reproductive characteristics of this species in Alagol, Almagol and Adjigol wetlands. A total of 1284 specimens were collected, and their biometrical data measured. The sex ratio of male to female for the whole region was estimated to be 1: 1. 29. This ratio was different between wetlands. Females were dominated the length groups of 12-20 mm, while males were more frequent in length groups of 24 mm and larger. The spawning season was started in early spring and lasted till mid-summer. The mean condition factor was estimated 1. 038 for males and 0. 64 for females. The mean batch fecundity ranged from 342 in Alagol to 3722 in Adjigol. The relationship of batch fecundity with carapas length and total weight showed an exponential model. The highest volume of the oocytes was observed in Alagol, and the lowest one in Adjigol. The carapas length at first maturity was estimated as 12. 1 and 13. 2 mm for males and females, respectively. Its high fecundity, small first length of maturity, and spawning during warm-water fish farming makes prawn broadly distributed in the area, therefore it is difficult to eliminate it from the inland water ecosystems.

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.

The effect of different bycatch reduction devices in decreasing bycatch of commercial fish species with the length of less than LM50 (the length from which, 50% of them are matured) in shrimp trawlers were examined. The experiments were conducted in Persian Gulf (Bushehr and Hormuzgan provinces) during the shrimp season, years 2000-2001.In this study four types of bycatch reduction devices (Grid, Nafted, Fish eye and Square mesh window) were used. Double rig trawl was used, one of them as an experimental trawl and the other as the control.Different treatments like one device or two devices were installed on experimental shrimp net. After hauling the trawl, frquency of different commercial species with length less than LM50 was determined in both nets, and the results were tested with Paired Willcoxon test. The results have shown that although all the devices have a reductional effect on bycatch of the young and juveniles of commercial species, but the amount of reduction with setting Nafted and Grid, either single or combined with another BRD was significantly higher than the control one (P ≤ 0/05). The amount of by catch reduction devices with different treatment (different devices either single or paired) according to the season of the experiment were also tested with Kruskal- Wallis test, which shows significant differences (P≤0.05) between the frquency of young and juvenile individuals of some species during different experimental seasons.According to this study, by using Nafted and Grid devices in the trawl nets of all shrimp vessels during its season, about 400 to 500 thousand of juveniles and young individuals can escape from the nets.

This study was designed for understanding reproductive biology of Kiddi shrimpParapenaeopsis styliferain western coastal waters of the Hormozgan province. Sampling was carried out monthly for period 15 months, from October 2015 to December, 2016. A total 835 shrimp included 462 femalesand 373 males were collected monthly by a stop set net. The sex ratio identified that it was not aconstant 1: 1 throughout the year, with 53. 3 % of shrimp was females. The recorded resolts show that the kiddi shrimps can spawn all year round and have two determine peak of spawning time from March to May and November to December. The gonado-somatic index (GSI) for female shrimps showed that the ascending trend from December to March but a descending trend of this index recorded in summer and maximum value was observed in February. Length at first maturity (LM50) for female was 18. 8 mm of carapace length.