484 research outputs found
Reproduction and feeding biology of Sind Sardinella (Sardinella sindensis) from coastal waters of Qeshm Island, Persian Gulf
Sardinella sindensis is one of the dominant small pelagic fishes of Persian Gulf, especially in Qeshm Island's coastal waters. Investigation on some of the biological parameters of Sind Sardinella was carried out from April 2005 to March 2006. Sind Sardinella is economically the most important small pelagic fish species mainly caught by double boat purse seine in this area. Reproductive studies showed that peak maturity season occurred in May. The female to male ratio was calculated at 1:1.08 and chi-square analysis showed the difference in ratio was not statistically significant (P>0.05). LM_(50) is attained at a total length of 112 mm. The average absolute and relative fecundity were estimated to be 23396 (± 5337) and 739 (±117), respectively. This fish is planktonivore, and we found the diet of the species consisted of a broad spectrum of food types, but Crustaceans were dominant, comprising 44% of the food. The other major food groups and their share were Dinophyceae 17%, Bacillariophyceae 15%, Cyanophyceae 13%, fish eggs, larvae, scale 7% and finally Euglenahyceae, Chlorophyta, and others 4%. Analysis of monthly variation in the stomach fullness indicated that feeding intensity fluctuated throughout the year, with a high level during March and April. Vacuity index indicated this species is a semi-voracious fish
Population dynamics of Sind Sardine, Sardinella sindensis, in coastal waters of Qeshm Island
Sardinella sindensis is economically the most important small pelagic fish species in the coastal area of Qeshm Island. Population dynamics of Sind sardinella from Qeshm Island coastal waters, during April 2005 to March 2006 were studied. The asymptotic length (Lx) and growth coefficient (K) were estimated at 178mm and 1.11yr ^(-1), respectively. The minimum and maximum T.L was recorded at 42 and 172mm respectively. The value of t0 was calculated at -0.17, and Tmax was estimated at 2.7 year. The Von Bertalanffy growth equation was obtained at L_(t) = 178^(1-exp(-1.1 l(t-(-0.17))) for this species. Total mortality (Z) rate was estimated to be 3.48yr ^(-1) (r ^(2) = 0.88) on length-converted catch curve method. The rates of natural mortality (M) based on Pauly's empirical equation, fishing mortality (F) and exploitation ratio were estimated at 1.13yr ^(-1), 2.35yr ^(-1) and 0.67, respectively. Four cohorts were distinguished annually based on Bhattacharya's method with mean length of 56, 89, 107 and 141mm. Maximum recruitment was in September at 18.62 percent. The length-weight relationship was determined as W= 0.000005 L ^(3.1399)
Spatial and temporal variations of phytoplankton population in coastal waters of Hormozgan province (Qeshm and Leangeh)
The relationship between diversity or density of phytoplankton and other marine fisheries sector is of great importance. The study of Spatial and temporal variability of distribution of phytoplankton communities in the coastal waters of the Northern Persian Gulf (QESHM, LENGEH) were studied during 2008. In this study, five groups (47 genera) of phytoplankton include, Bacillariophyceae, Dinophyceae, Cyanophyceae, Crysophyceae and Euglenophyceae were identified. The result showed that Diatoms group (79.6 %) and Rhizosolenia genus (45.5 %), contributed more towards the percentage composition of different groups and genera of phytoplankton at the during Study. The annual changes in relative abundance and Margalef, Shannon, pielu and Simpson indices were estimated, 0.58-2.56, 0.08-0.97, 0.23-2.6, 0.09-0.93 respectively. Multivariate analysis of variance showed that during the study, density and biological indicators of phytoplankton were significant between seasons (p<0.05). The spatial cluster analysis based on similarity coefficients obtained two clusters in the areas studied. According to the results obtained can be concluded that both the area of ecological conditions in ranks are instead moderate. Also, phytoplankton of diversity and richness is good
Reproduction and feeding of Buccaneer anchovy (Encrasicholina punctifer) from coastal waters of Qeshm Island, the Persian Gulf
Encrasicholina punctifer is one of the dominant small pelagic and economically most important fishes of the Persian Gulf, especially in Qeshm Island's coastal waters. Specimens of the fish were collected monthly from the fishing area in the coastal waters of Qeshm Island by random sampling method. Investigation on biological parameters of E. punctifer continued from April 2005 to March 2006. E. punctifer is mainly caught by double-boat purse seine in this area. Reproductive studies showed that maturity season of the fish occur in August. The sex ratio fulfill the theoretical 1:1 (P>0.05). L sub(M50) was attained at a total length of 84 mm. The absolute fecundity was estimated at 1217 plus or minus 331. We showed that the species is planktonivore, its diet consisted of a board spectrum of food types, but crustaceans dominated the food with copepods and their eggs, naplius and semi digested copepods constituting 54% of the diet. The next major food groups found in the diet of the fish were Cyanophyceae 21%, Bacillariophyceae 11%, fish egg and scale 6%, Dinophyceae 4%, with Euglenahyceae, Chiorophyta, Dinoflagellates and others items consisting only 4% of the diet. Analysis of monthly variation in the stomach fullness indicated that feeding intensity fluctuated throughout the year, with the highest value in winter. Vacuity Index indicated this species was of semi-voracious appetite fishes
Population dynamics and reproduction biology of slender mudskipper (Scartelaos tenuis) from Hormuzgan Province creeks, Persian Gulf
Slender Mudskipper (Scartelaos tenuis) is one of the dominant fishes in inter-tidal mud flats area. Reproduction and population parameters of 2047 Slender mudskipper were studied monthly from october 2008 to september 2009. The asymptotic length (L∞) and growth coefficient (K) were estimated as 19.43(cm) and 0.64(yr-1), respectively. The minimum and maximum T.L. was 1.1 and 19.5cm, respectively. The value of to was -8.28, and Tmax was 4.6 year. The growth equation of Von Bertalanffy was obtained at L(t) = 19.43(1- exp (-0.64(t(-0.28))) for this species. The rates of natural mortality (M) on Pauly's empirical equation, was estimated 1.51 (yr-1). Five cohorts were distinguished annualy on Bhattacharya's method with mean length of 7.89, 11.42, 13.86, 15.6 and 16.81cm. Maximum recruitment was in Seprember at 18.8 percent. Reproductive studies showed that peak of maturity season occurred in April. The female to male ratio was calculated as 1:1.47 and chi-square analysis showed that it was statistically significant deviated from 1:1. LM50 is attained at a total length of 13.3cm. The mean of absolute and relative fecundity were 6742 (±1939) and 707 (±210), respectively. The length-weight relationship was as W= 0.02735 L 2.1655, that was isometric growth. Result showed that slender mudskipper population was in congenial condition, nevertheless less not evaluated
Two-qutrit Entanglement Witnesses and Gell-Mann Matrices
The Gell-Mann matrices for Lie algebra su(3) are the natural basis
for the Hilbert space of Hermitian operators acting on the states of a
three-level system(qutrit). So the construction of EWs for two-qutrit states by
using these matrices may be an interesting problem. In this paper, several
two-qutrit EWs are constructed based on the Gell-Mann matrices by using the
linear programming (LP) method exactly or approximately. The decomposability
and non-decomposability of constructed EWs are also discussed and it is shown
that the -diagonal EWs presented in this paper are all decomposable
but there exist non-decomposable ones among -non-diagonal EWs.Comment: 25 page
Physical and mechanical properties of Oak (Quercus Persica) fruits
This research was conducted over one Iranian variety of Oak (Quercus Persica) with 70 observations. Physical and mechanical properties of oak are necessary for equipment used in activities such as transportation, storage, grading, packing etc. Properties which were measured include fruit dimensions, mass, volume, projected area, fruit density, geometric mean diameter, sphericity and surface area. Bulk density, porosity and also packing coefficient were measured. Experiments were carried out at Results showed that average mass and volume were 12.95 g and 10.27 mL, respectively. Dimensions increased from 41.85 to 61.09 mm in length, 14.45 to 25.02 mm in width and 14.42 to 24.38 mm in thickness. The mean projected area perpendicular to length, width and thickness obtained 433.91, 1085.48 and 1115.46 mm2, respectively. The geometric mean diameter and surface area were calculated as 27.638 mm and 2423.82 mm2, respectively, while sphericity was measured 51.78%. Elasticity modulus (E), maximum force which fruit can support (Fmax) and work which performed to this force have been determined
Study of existing biological communities in Hormuzgan province waters (Persian Gulf) for installation of artificial reefs
To determine the suitable locations for installation of artificial reefs we studied Persian Gulf waters (Hormuzgan province) from December 2006 to March 2007 seasonally. The area was stratified to 10 transects and each transect was divided to three layers and used random sampling method. Habitats of fauna and flora including: Communities of corals, seaweeds, sea cucumbers and sea grasses, and sedimentation depth using SCUBA diving method were studied in each transect and layer. Sea grass communities existed in some places with below 10m depth of Bandar Mesan, Bandar Kang, Kish Island and Bandar Chirooyeh transects. Also, seaweed habitats were seen in Bandar Mesan and some areas in Bandar Lengeh and Kish Island in 10-20m depth transect. The study of coral and sea cucumber communities indicated presence of Acropora sp. habitats in Bahman jetty, Bandar Mesan and Bandar Bostaneh transects , and Porites sp. habitats in Hengam island transect, Holothuria sp. habitats in Bandar masen and Bandar Lengeh transects and Stichopus sp. habitat in Hengam Island transect. All these species were found in shallow waters bellow 10 meters depth and showed a patchy distribution. Sedimentation depth results showed a statistically significant difference between layer <10m in Bandar Salakh and the same layers in other transects, also between layer 10-20m and 20-30m in other transects. Based on the sedimentation depth and habitats studies, we recommend layer 10-20m in Bandar Lengeh area and Bandar Lengeh to Hendurabi Island area as suitable for artificial reefs installation
Constructing Entanglement Witness Via Real Skew-Symmetric Operators
In this work, new types of EWs are introduced. They are constructed by using
real skew-symmetric operators defined on a single party subsystem of a
bipartite dxd system and a maximal entangled state in that system. A canonical
form for these witnesses is proposed which is called canonical EW in
corresponding to canonical real skew-symmetric operator. Also for each possible
partition of the canonical real skew-symmetric operator corresponding EW is
obtained. The method used for dxd case is extended to d1xd2 systems. It is
shown that there exist Cd2xd1 distinct possibilities to construct EWs for a
given d1xd2 Hilbert space. The optimality and nd-optimality problem is studied
for each type of EWs. In each step, a large class of quantum PPT states is
introduced. It is shown that among them there exist entangled PPT states which
are detected by the constructed witnesses. Also the idea of canonical EWs is
extended to obtain other EWs with greater PPT entanglement detection power.Comment: 40 page
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