180 research outputs found
Reproduction biology of Penaeus merguiensis (banana prawn) emphesis of fecundity in coastal waters of Hormozgan Province, Iran
Penaeus merguiensis is the dominant species in coastal waters of Hormozgan province and approximately constitute 70% of the annual catch composition. Sex rate is analysis in natural population shows that the proportion of males to females is 1:1 and generally this proportion in carapace length is 28.6 and 25.7 mm more than other classes, which its peak is observed in 25.7 mm length class. Also proportion of males to females in May to December and April to May is more than other times which its peak is in December. The analysis of sexual maturation based on carapace length shows that LM50 for females of this species has followed the exponential equation and is equal to 32.8 mm (r^2 = 90%). Minimum and maximum of absolute fecundity of this species with 20.7-31.5 mm C.L. are and 11300 and 14400 eggs respectively. This analysis of relative fecundity of this type showed that the relationship between carapace length and number of eggs was a type of poweral equation (F= 0.1208 C.L 3.8, r^2 = 97%), however this relationship between total length (T.L) and wet weight (W) was F = 0.0002 T.L 7.1 (r^2= 0.68) and F= 0.1942 W 4.02 (r^2=0.58), respectively, which showed the fecundity has 0.1942 W (r more correlation with the carapace length
Cisgenic inhibition of the potato cold induced phosphorylase L gene expression and decrease in sugar contents
To decrease the accumulation of reducing and non-reducing sugar in potato tubers stored at low temperature, a single gene silencing vector pARTPhL-IR, harboring a part of starch phosphorylase L gene as inverted repeats with pdk intron within was constructed and transformed into potato (Solanum tuberosum L.) cultivars Agria and Marfona. Polymerase chain reaction (PCR) of nptII gene and pdk intron indicated that the RNA interference construct was transformed successfully into the genome. Real time RT-PCR analysis of starch phosphorylase L gene in stored microtubers for 90 days at 4°C showed that the expression level of this gene in transgenics ranged from 1.63 to 7.54% of that in the non-transgenic plants. Analysis of sugar content in these plants showed that the total sugar content in transgenic microtubers was significantly reduced compared to the control, up to 35% in line M4. The accumulation of reducing sugars in transgenic lines at 4°C was reduced from 9.13 (in Agria) to 5.57 mg/g fresh weight (transgenic line A5) and from 9.56 (in Marfona) to 6.52 mg/g fresh weight (transgenic line M4), implying that silencing of starch phosphorylase L gene reduced starch breakdown during cold storage conditions.Key words: Cold sweetening, potato (Solanum tuberosum L.), RNA interference, starch phosphorylase L. gene
The effects of broodstock age on consecutive spawning performance of wild-caught ablated Fenneropenaeus
The effects of broodstock age on consecutive spawning performance of wild-caught ablated Fenneropenaeus indicus females in four age groups 6, 8, 12, and 14 months old were studied. Assessment duration was 30 days. Age groups were determined based on carapace length of broodstock caught from Jask fishing ground. Maximum female partnership percentage in consecutive spawning was for 12 months old group. Correlation between egg production and hatch in each spawning with number of spawning in 12 months old broodstock was weaker than other groups but this relation has negative and significant (r = -0.38, P0.05) but others groups had significantly higher hatch rate (P<0.05). In general, 12 month group of wild-caught ablated Fenneropenaeus indicus females showed much higher number of egg produced, hatch percentage, females partnership percentage for 4 spawning in the 30 days period
Organizational sustainability: A new project portfolio management approach that integrates financial and non-financial performance measures
This paper presents preliminary research on a new decision making tool that integrates financial and non-financial performance measures in project portfolio management via the Triple Bottom Line (TBL) and uses the Analytic Hierarchy Process (AHP) as a decision support model. This new tool evaluates and prioritizes a set of projects and creates a balanced project portfolio based upon the perspectives and priorities of decision makers. It can assist decision makers with developing and making proactive decisions which support the strategy of their organization with respect to financial, environmental and social issues, ensuring the sustainability of their organization in the future
Fishing pattern, maximum constant yield (MCY) and recruitment pattern of Thunnus tonggol in Hormuzgan province
Thunnus tonggol is one of the most important large pelagic fish species in Hormuzgan province waters. Nominal catch of T. tonggol in 2010 was 32405 tones comprising 65% of total catch of large pelagic fishes. For sustainable exploitation of the resources of this fish, we need to identify its fishing pattern, maximum constant yield and recruitment pattern. Hence, length and weight data were collected randomly from 6 major artisanal fish-landing sites Hassineh, Kong, Bandar Abbas, Salakh, Sirik and Jask in Hormuzgan province, starting in April 2010 over one year. Growth parameters L∞ and K were estimated at 112.23cm 0.3 and (1/year), respectively. Hence, the natural mortality was calculated at 0.43 (1/year) and the maximum constant yield was computed at 11880 tones. Length-weight power relationship, W= aFLb , was W= 3×10-05FL2.82 that showed T. tonggol have isometric growth. Fishing pattern indicated that almost 85% of the catch was under the size at first maturity. Maximum recruitment pattern was in November with average fork length being 27cm. For optimum exploitation of T. tonggol stocks, we suggest two approaches including fishing ban in the maximum recruitment time and gear (Drift gillnet) modification
Age and growth of sind sardine (Sardinella sindensis) using otolith from Qeshm Island (Persian Gulf)
This is the first study of growth and age of Sardinella sindensis from coastal waters of Qeshm Island (Persian Gulf) based on the sectioned otolith reading method. In total, 128 fishes were collected randomly from purse seine commercial nets during March 2011 to February 2012. The annual formation of the growth rings were determined by counting the opaque and translucent zones occurrence at the outer margin of the otolith. The peak of opaque and translucent zones formation occurred in June and January, respectively. There was no significant differences between the sex ratio of males to females (p>0.05). The total length and body weight for both sexes ranged between (7.9-18.6 cm) and (3.98-55.69 g). In total, four age classes were determined, and the maximum age was recorded as 3.5 years. The most abundant individuals were counted in 1+ age class, while the least number of fishes belonged to the 3+ age class. The non-linear regression relationship between the length and age for combined sexes were fitted in Von Bertalanffy growth equation, and described as: TL= 20.8 (1-e^-0.54(t+ 0.54)). There was a strong relationship between the body weight and total length of the fishes (p>0.05), indicating that the growth type of S. sindensis is isometric. From the results of this study we concluded that S. sindensis is a fast-growing species with a short-life span. In order to obtain more reliable results about the age and growth of this species, we suggest that different methods of age determination should be used, combined with the evaluation of the factors affecting its growth for the management of optimum exploitation of the resources of this fish
Essential fish habitats (EFH) of small pelagic fishes in the north of the Persian Gulf and Oman Sea, Iran
Small pelagic fishes particularly anchovy (Encrasicholina punctifer) and sardine (Sardinella sindensis) have an important role to support the Iranian fisheries and are distributed along the coastal waters of the Persian Gulf and Oman Sea. Using a logbook on small pelagic fisheries, a GIS-based environmental modeling approach was applied to investigate the presence and abundance of anchovy and sardine in relation to environmental variables. Redundancy analysis (RDA) was applied to provide a preliminary view of the relationships between fish presence/absence and environmental variables. Generalized Additive Models (GAMs) indicated the presence/absence of fish was related to distance from the nearest coast, depth, sea surface Chlorophyll-a, and SST. Results of the EFH showed that sardine is concentrated in specific areas of more favorable conditions, such as north of the Persian Gulf and all areas of the northwest of the Oman Sea. However, EFH of anchovy showed a more widespread distribution, occupying most of the north-west of the Oman Sea coastal waters, south of Qeshm Island in the Strait of Hormoz as well as the Parsian district in the north of the Persian Gulf. In this study, it seems that the anchovy showed the probability of presence in the areas with more distance from the coastal waters. However, the EFH probability presences of sardine were predicted for near coastal water and obviously, shallower waters. Due to the development of small pelagic fisheries, it is highly recommended to investigate anchovy and sardine fishing possibility in areas with high EFH prediction probability
Growth parameters and mortality rates of Liza klunzingeri in the Iranian waters of the Persian Gulf and Oman Sea, using Length Frequency Data
The aim of the present study was to investigate the population dynamics of Liza klunzingeri, in Hormouzgan province waters located in northern coasts of the Persian Gulf and Oman Sea. This study was carried out from October 2007 to September 2008. Samples were collected from commercial stake traps. The relationship between weight and fork length was found to be W= 0.0214 F.L^2.8233 suggesting that Liza klunzingeri shows isometric growth. Length-based stock assessment using the FiSAT software package showed an asymptotic length (L∞) of 20.3cm FL and growth coefficient of 0.6.yr^-1. These results gave a growth performance index (ø) of 2.39. The total mortality coefficient was estimated to be 2.31, a natural mortality of 1.09 and fishing mortality of 1.22. The estimated total mortality which, in relative terms, is considered average (2.31.yr^-1), coupled with the currently observed exploitation rate of 0.52 for L. klunzingeri, estimated from the mortality rates, suggested that the species is moderately exploited
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