Population biology and assessment of Kawakawa (Euthynnus affinis) in coastal waters of the Persian Gulf and Sea of Oman (Hormozgan Province)

Length composition data (fork length) of kawakawa (Euthynnus affinis ), landed between April 2003 to March 2005 in Coastal Waters of Hormozgan province in Iran ( Persian Gulf and Sea of Oman) , were monthly used to estimate the p opulation parameters and for the assessment of the stock. The growth parameters of von Bertalanffy equation were estimated as L∞: 87.66 cm, K: 0.51 per year and t0: -0.23 year. The estimated value of total mortality, natural mortality and fishing mortality were Z: 2.37, M: 0.65, F: 1.72 per year, respectively. Exploitation ratio (E) and Exploitation rate (U) were estimated as 0.72 and 0.65. The Annual total stock at beginning of year was calculated to be 7924 t and Annual average standing stock (S) was equal to 2994 t. By using analyses knife-edge selection method, biological reference points for kawakawa stock was calculated as, Y'/R (relative yield per recruitment) =0.062, B'/R (relative biomass per recruitment) =0.13, F max (Fishing mortality at maximum sustainable yield) =1.6, E max (Exploitation ratio at maximum sustainable yield) = 0.68 Fopt (Precautionary average target ) =0.33 year-1 and Flimit=0.43 year-1. As the exploitation ratio of kawakawa stock in this study was calculated to be over 0.5, it strongly recommended minimizing the fishing activity in this area

Quality control in Orange-spotted grouper, Epinephelus coioldes, during ice storage

In this study, changes of TMA and its relation with bacteria count was evaluated in Orange-spotted grouper, Epinephelus coioides during ice storage at 18th day. TMA and bacteria count changes were evaluated at days 0, 3, 6, 9, 12, 15, and 18. TMA increased at days 0, 3 and 6 but changes during these days were not noticeable and it showed no significant differences (P>0.05). By passing time and from day 9 amount of TMA showed increased compared with other days and had significant difference in the value (P<0.05) such I that reached from 0.96 (day 0) to 12.46ms/100g (day 18). The psychrophilic bacteria showed a more monotonous change relative to the mesophilic bacteria and became dominant in ice through time. Logarithm of colonies of the psychrophilic bacteria per gram increased from 1.37 at day 0 to 7.72 at day I 8th. The mesophilic bacteria showed fluctuations in their number such that at day 15th they decreased and at day 18th, increased. The level of TMA showed significant difference between the first days and last days (P<0.05) such that they increased from 2 at day 0 to 4.61 at day 18th. Bacterial count especially *psychrophilic bacteria were increased during storage, whereas mesophilic bacteria decreased at day 15 of storage. TMA showed relationship with psychrophilic bacteria and storage days (P<0.05, R=0.98)

Age, growth and length at first maturity of Otolithes ruber in the northwestern part of the Persian Gulf, based on age estimation using otolith

Estimates of age, growth parameters, length-weight relationship and length and age at first maturity of the otolithes ruber are required for fishery management. We used counting annuli on the section of sagittal otoliths to age O.ruber from the Northwest Persian Gulf in south of Iran. Estimated ages ranged from 0 to 6 years, and maximum frequency of fishes was observed in age-group 1. The values of growth parameters L∞, k and to were calculated by von Bertalanffy model and the results were 67.57 (cm), 0.27 (year-1) and -0.43 respectively. Parameters b and an in length-weight relationship were calculated 3.19 and 0.005 respectively. Length and age at first maturity were estimated 28 cm and 1.55 year

Ecological quality of Bahrekan coast, by using biotic indices and benthic communities

1 - The aim of this study was identifying macrobenthos biodiversity and an assessment of the ecological quality status of Bahrekan coast in Persian Gulf, using AMBI, Bentix indices according to softbottom marine benthic communities. Other ecological indices, such as theShannon diversity index (H`) and the species richness ( S ) were also applied and evaluated comparatively. 2 - In total, 111 genus/species were recognized, divided into 17 groups with gastropodas always dominant and the substrate in all of the stations was characterized as muddy bottom. 3 - The macrobenthic animals according to their sensitivity to an increasing stress gradient, were classified in 5 ecological groups. 4 - Due to the high dominance of species such as Pyrgohydrobia sp., Tornatina sp., Melinna sp., Cossura sp. and Sternaspis sp, diversity values were reduced. 5 - According to the results of AMBI, BI, Bentix, and H`indices Bahrekan coast is classified in slightly to moderate pollution status

The innate immunity changes of the female anadromous hilsa shad, Tenualosa ilisha , during spawning and post spawning season

Tenualosa ilisha (Hamilton) is a valuable migratory fish belonging to the family Clupeidae and it is distributed in a wide area from the Persian Gulf to coasts of Pakistan and China’s southern sea. The aim of the present study was to investigate the changes occurring in innate immunity parameters during upstream migration and comparing them to those during post spawning. Sixty mature female hilsa shad were obtained using gill net from Karoon River in Khorramshahr during the spawning period (July, August and September 2014) and Hendijan coasts along the Persian Gulf coasts during post spawning period (October, November and December 2014). Immediately, blood samples were collected from the peduncle vein and then parameters including WBC (White Blood Cell) count, Differential WBC Count, plasma lysozyme content and C3 and C4 complement activity were determined. Based on the results, the levels of WBC, lysozyme and C3 during the spawning period were lower than those recorded during post spawning period. However, C4 levels were higher during spawning (p<0.01). This fact revealed that some innate immunity parameters experience depression during upstream migration and spawning, while these parameters increase during the post spawning period, indicating the suppressive effects of spawning on fish immunity

Intestinal digestive enzyme activity under the influence of different dietary supplements methionine and lysine in the diet of Sparidentex hasta

This study was conducted to determine the effects of dietary methionine and lysine supplementation on digestive enzymes activity in juvenile Sobaity, Sparidentex hasta. For this purpose, 180 juvenile fish with an initial average weight of 31.38 ± 1.4 g were distributed randomly in eighteen (300 L) polyethylene tanks. 6 experimental diets were prepared with different levels of methionine and lysine including control diet (without dietary methionine and lysine), Diet 1: 100% methionine; Diet 2: 75% methionine and 25% lysine; Diet 3: 50% methionine and 50% lysine; Diet 4: 25% methionine and 75% lysine; Diet 5: 100% lysine. During the experimental period, fish were fed to satiation thrice daily (8:00, 13:00 and 18:00 hours) for 8 weeks. At the end of the experiment, digestive enzymes (trypsin, chymotrypsin, alkaline phosphatase, amylase, lipase and total protease were affected by different dietary levels of methionine and lysine supplementations (P<0/05). Also, the activity of trypsin and chymotrypsin had shown an increasing trend with an increased amount of diet lysine while enzyme activity of alkaline phosphatase was higher in treatments contains the maximum amount of methionine supplementation. According to results, the increasing of lysine in diet reduced enzyme activity of lipase. The results, showed no significant differences between experimental treatments in amylase and total protease (P<0/05). Based on the results of evaluation digestive enzymes, amino acids supplements of lysine and methionine were changed the activity of digestive enzymes in juvenile Sobaity, (S. hasta). Finally, Diet 2 with 75% methionine and 25% lysine was suggested for used by Sobaity, as to the balance of dietary methionine and lysine supplementation

The amino acid compositions of muscle from wild and cultured of male and female Acanthopagrus latus

The crude protein content and amino acid compositions of muscle from wild and cultured of male and female Acanthopagrus latus were determined by HPLC. There were quantitative differences between individual amino acids in the tissues investigated, depending on the sex and location. It was noted that, among all the samples studied in tissues, sexes and locations, lysine and isoleucine were the principal essential amino acid (EAA) and glutamic acid was mainly for non-essential amino acid (NEAA). Lysine and isoleucine of male muscles had a significantly higher (P0.05) level of EAA than other groups. The results indicate that the Acanthopagrus latus is a healthful component of the human diet

Effects of short-term starvation on biochemical carcass composition, liver glycogen and fat in silver seabream fingerlings, Sparidentex hasta

Both in nature and in aquaculture, fishes coulde xperience periods of food deprivation or starvation. The present study was investigated the effect of starvation on biochemical body composition, glycogen and fat of liver in Sobaity fingerling. In this study, 300 fingerlings of Sparidentex hasta studied with mean weight 28.47±0.24 g that included four treatments each with three replicates (25 fish per replicate) in a 300-liter polyethylene tanks. Fish of control treatment were fed to saturation twice daily and other treatments of were starved 2, 4 and 8 days. Biochemical composition of liver and carcass were performed at the beginning and end of the period of starvation and samples were transported to the laboratory for analysis. The results of this study showed that 2 days of food deprivation did not affect any of the factors studied (P>0.05), also 4 days of food deprivation was significantly affected on liver glycogen only (P<0.05), but 8 days of food deprivation was significantly effected on liver glycogen, fat and protein of body composition (P<0.05). According to the results of this study it can be stated that; in Sobaity fish, the first priority was the use of liver glycogen stores in food deprivation times; this shows the key role of the liver as the provider of fish body's energy needs, and the next priority was the use of fat and protein stores

Catch length structure, mortality and exploitation of Otolithes Ruber during the ten-year period (2000-2010) in the northwest of Persian Gulf

In the present study, length structure, mortality and exploitation rate of Otolithes ruber during a ten-year period were studied. Sampling was carried out by using bottom trawl net in the fishing area in Northwest of Persian Gulf over 1 year study period. Length data was also collected from fisheries research institute and fishery organization. Age determination was done by reading annual rings on sectioned otolith. Growth parameters were calculated based on age and length data. These data were used to estimate natural mortality rate. Total mortality was obtained from the age curve. Logarithmic catch and natural mortality were calculated from Pauly's equation. The averages of length in the last ten years were 35 to 39 cm. The samples ranged in length from 12 to 58 cm with the maximum frequencies between 28-44 cm. Length distribution was normal in this study. The maximum catch was composed of fish in the 40 to 48 cm length range with an average age of 2 to 3 years. The average total mortality, natural mortality and fishing mortality were 0.98, 0.56, and 0.42 respectively. Mortality was higher in age group 0 and age group 1, but mortality of the other age groups dramatically decreased. Exploitation rate in the last ten years were 0.42 indicating a near complete exploitation. Based on the results a more effective exploitation strategy is suggested in this region

Effects of supplementation of amino acids, lysine and methionine on growth performance and feed utilization of sobaity sea bream juveniles, Sparidentex hasta

This study was conducted to determine the effects of dietary supplementation of lysine and methionine on growth and nutrient utilization of Sobaity sea bream, Sparidentex hasta.A total of 180 juvenile fish with an initial weight of 31.38 ±1.4 g were distributed randomly among eighteen tanks. Fish were fed to satiation three times per day (08:00, 13:00 and 18:00 hours) for 8 weeks with formulated diets containing six different levels of dietary methionine and/or lysine; Diet 1: a control diet without dietary amino acid supplementation; Diet 2: 100% methionine supplementation; Diet 3: 75% methionine and 25% lysine supplementation; Diet 4: 50% methionine and 50% lysine supplementation; Diet 5: 25% methionine and 75% lysine supplementation and Diet 6: 100% lysine supplementation. The results of this study showed that dietary lysine and methionine supplementation significantly affected (P<0.05) growth parameters and feed utilization. The fish fed with high level of methionine supplementation had significantly improved growth performance than the group fed the control diet and treatment 6. Highest feed conversion ratio, protein efficiency ratio and protein retention were observed in diet 3. Though lysine and methionine supplementation showed positive effects on growth and feeding performance, our results suggested that Sobaity juveniles probably required more methionine than lysine