958 resultados para THERMOCLINE WATERS
Resumo:
Results of comprehensive efficiency tests of three tested designs of 15m bulged belly, 15.8m six seam and 29.26m longwing type trawls in combination with 114x57cm both rectangular flat and horizontal curved wooden otter boards are reported. Of the possible six combinations, the bulged-belly trawl with flat rectangular otter boards has performed better in landing prawns. Further this study has indicated the selective action of the different designs.
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Results of a preliminary study of the hexane extractable carbonyls from three fish and one shell fish are reported. Volatile carbonyls that can be isolated from oil sardine by distillation at different temperatures in air or nitrogen atmosphere were also studied. Carbonyls were converted to their 2:4 dinitro phenyl hydrozones. These were fractionated by column chromatography and the different fractions were analysed by capillary gas chromatography. The data show wide variations in the content of different carbonyls in different fishes. Carbonyls in distillates from muscle water homogenates of oil sardine showed some differences from the carbonyls extracted with hexane from the same fish. More data is necessary to correlate the carbonyls with the characteristic flavour of each fish.
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Descriptions with suitable illustrations of two species of palaemonid prawns - Macrobrachium aemulum and Palaemon (Palaemon) concinnus are furnished. M. aemulum has been enjoying an isolated distribution in New Caledonia. It is reported for the first time from India and is therefore a clear case of discontinuous distribution. Studies revealed that M. aemulum is distinct from M. nobilii and the reasons for separating the two species are discussed. New distributional records for P. (P.) concinnus in the south-west coast of India are also given.
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Diagnostic characters for the identification of postlarval Penaeus appearing along the coastal waters of the Philippines are reviewed and categorized, based on materials from the wild and laboratory. Presently there are 7 adult known species belonging to the genus Penaeus around Panay Island and its adjacent waters, namely: P. monodon, P. semisulcatus, P. merguiensis, P. indicus, P. japonicus , P. canaliculatus, and P. latisulcatus.
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Catch data of Scylla serrata obtained in different gears from Karwar region during December 1983 — November 1984 indicated a sum of 9608 kg of landings of crabs. Majority of the crabs (89.57%) was found to be caught in backwaters by line fishing and cast nets. A considerable (10.43%) quantity of catch was also contributed by gill nets and shore-seines from inshore waters. A maximum of 1207 kg of crabs were landed in December, 1983. The size structure and sex-ratio of S. serrata varied with gear type and period.
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This paper deals with the levels and distributions of nutrient salts in the United Arab Emirates waters. Water samples were collected bimonthly during 1994-1995 from the marine environment of the United Arab Emirates, which extends more than 800km along the Arabian Gulf and the Gulf of Oman. Concentrations of ammonium, nitrite, nitrate, phosphate, silicate, as well as total concentrations of total dissolved nitrogen, phosphorus, and silicon in the area were scattered in the ranges: (ND-6.32; mean: 0.84 µg-at N/l), ND-3.02; mean: 0.42 µg-at N/l), (ND-10.88; mean: 1.18 µg-at N/1), (ND-4.22; mean: 0.62 µg-at P/l), (1.14-28.80; mean: 6.52 µg-at Si/l), (1.52-39.58; mean: 12.28 µg-at N/l), (0.40-4.98; mean: 1.07 µg-at P/l), and (2.77-44.74; mean: 13.02 Si/l) respectively. Of inorganic nitrogen species, ammonium was the highest in the Arabian Gulf waters and nitrate was the highest at the Gulf of Oman. The dissolved inorganic nitrogen total species, phosphate and silicate amounted to 16.4, 47.6, 56.5% respectively, of the concentrations of nitrogen, phosphorus and silicon in the Arabian Gulf and 22.6, 64.4, 44.9% respectively, in the Gulf of Oman, indicating that more than 80% of nitrogen was present in organic forms. Distributions of nutrient in the two regions were higher in the summer season and lower in the winter season due to the oxidation of organic materials. Regional distributions revealed higher values for nitrite (1.3 times), nitrate (2.8 times), phosphate (2.2 times), total dissolved nitrogen (1.3 times), total dissolved phosphorus (1.6 times), and total dissolved silicon (1.3 times) in the Gulf of Oman compared to the Arabian Gulf, indicating more oligotrophic conditions at the Arabian Gulf Whereas no distinct patterns of distribution were observed in the Arabian Gulf waters, an increase in the seaward direction was measured at the Gulf of Oman. Vertical distributions indicated a general increase with depth in the two regions. The mean ratios for total concentrations of phosphorus, nitrogen, and silicon in the Arabian Gulf (1: 11.6: 12.6) and the Gulf of Oman (1: 10.1: 11.8) were lower than the Redfield ratio.
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This work focuses on four marine sites in the Mediterranean Sea around the Nile Delta, Egypt. Surface water samples were collected seasonally during 2003. The concentrations of some heavy metals in dissolved form (Fe, Mn, Zn, Cu, Ni and Pb) are evaluated. The levels of heavy metals in the coastal waters were 11.92-30.4512µglˉ¹ for Fe; 5.79-17.36 µglˉ¹ for Zn; 0.30-0.83µglˉ¹ for Cu; 0.51-2.90µglˉ¹ for Ni and 0.53-10.31µglˉ¹ for Pb. These are compared, with sites in the estuaries and outlets of the Nile Delta. Fe (19.72-60.33µglˉ¹); Mn (12.63-35.60µglˉ¹); Zn (2.67-22.00); Cu (0.56-1.67µglˉ¹); Ni (1.43-3.73µglˉ¹); Pb (1.72-59.7µglˉ¹). The results showed a remarkable decrease in the concentrations of different heavy metals with increased salinity. Comparing the present data with the minimal risk concentration reported by WQC, the distribution of heavy metals was significantly lower in coastal sea water of the Mediterranean Sea off Egypt. The study indicated also that the average contents of Ni and Pb are slightly high in the area of water exchange than those reported by WQC.
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Previously an asteroid starfish Astropecten indicus has been described by Tahera (1996), and another species of the genus Astropecten i.e. A. polyacanthus Muller and Troschel, 1842 has been collected from the subtidal region of a sandy shore of Clifton (24°47'42"N 66°59'6"E), Karachi. The latter species is here reported for the first time from the Pakistan coast of the northern Arabian Sea and fills the gap in the known distribution. The species is briefly described and illustrated.
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Sphyraena jello, Pick handle Barracuda, is amongst the highly valuable and main commercial fisheries resources in the southern waters of Iran. Given such an economically significant position, this study, being conducted in 2006-2007, attempts to investigate its biological habit and characteristics in Iran’s water of the Persian Gulf. For the sampling purpose, three major landings namely Bushehr, Deylam and Genaveh were selected to obtain samples from commercial catches. The sampling is composed of 655 males and 515 females during a twelve month period. By studying the feeding through the counting method, it is revealed that, Liza subviridis characterized by %42.8 and Sepia pharaonis by %8.4 made the highest and lowest stomach content respectively. The findings showed that male fish in smaller size will mature sooner than females’ specimen but this gender ratio or proportion was not significantly different except during October and September. Such a difference between male and female in different months could be originated from longer residing of female group in spawning ground compared to male group. The previous spawning lasted during September –October, and there was a peak of spawning in feeding in August. The lowest fat proportion for both male and female genders was reported 0.10 and 0.11 respectively in October; but the highest level of condition factor was reported to be 0.59 and 0.63 during November and June.
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This study was conducted to determine reproduction characteristics, diet regime, age structure and population dynamics parameters of the vimba vimba persa (Pallas, 1811) in Mazandaran waters of the Caspian Sea, from October 2008 to September 2009. A total of 994 specimens were monthly collected by beach seine and cast net from six fish landings of Ramsar, Tonekabon, Chaloos, Mahmood Abad, Sari and Behshahr. Biometric characters were measured for each specimen at the laboratory. Scales were used for age determination. Sex determination and fecundity were determined. Population dynamic parameters as well as stock assessment including cohort analysis were estimated using FISAT software. The finding showed that the mean of fork length and body weight of the Caspian Vimba were 168.4±2.6 mm and 71.94±32.24 g respectively. Strong correlation was found between these two variables (a= 0.012; b = 3.047; r2 = 0.955). 92 specimens were studied from the fecundity point of view. This species was found to have more abundance in spring (esp. Apr-May). The samples composed of 397(42.6%) male, 537(57.4%) female; Overall sex ratio (M: F =1: 1.35) was significantly different from the expected 1:1 ratio (p ≤0.05). The advanced stages of maturity (4th & 5th) were found in April and May. The highest Gonadosomatic Index in female was in May and the lowest one was in July. This fish is therefore a spring spawner. The maximum absolute and relative fecundities were 34640 and 260.9, respectively; the minimum absolute and relative fecundities were 5400 and 94.5 respectively. The averages of absolute and relative fecundities were 17198±7710 and 171.85±48.8, respectively. Coefficient vacuity index was 59.2% which indicates that this fish is mesophagous. Among of living creature consumes by Caspian Vimba mollusks, 76 arthropods, worms, plants, detritus and fishes were found 32.9% , 26.7% , 13.4% , 17% , 4.4% and 1.6% respectively. The infinite fork lengths were 261 mm for females, 25mm for males and 261 mm for both sexes respectively. For population growth and mortality parameters; K ( 0.28 per year for both sexes, 0.3 per year for males, 0.33 per year for females); t0 ( -0.65 year for both sexes, -0.23 year in females, -0.51 year in males ); Φ' ( 2.28 ); Z ( 0.98 per year ); M ( 0.59 per year); F ( 0.39 per year) and Exploitation coefficient was 0.4. The analysis showed that total biomass and MSY were 1336 and 528.8 tonnes respectively.
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This study was conducted to determine biological characteristics and population dynamics parameters of threadfin bream (Nemipterus japonicus) in Persian Gulf (Bushehr Province), during November 2006 and October 2007. The minimum and maximum specimens were 75-273 mm FL and their weight was 7.6 - 351.9 g. Based on the exponential relationship between fork length and weight, slope (b) for individuals, males and females was 2.987321, 2.992546 and 3.007314, respectively. The emptiness value (V) was 45.6% and it shows that N. japonicus is a moderate feeder. The results of Fp indicates that crustacean with 78.2% are main foods, mollusca (27.7%), fishes (20.7%), polychaeta (19.2%) and Foraminifera (11.7%) were identified as minor foods and phytoplanktons (9.9%), nematoda(8.0%), echinodermata (2.3%) and sea weeds (0.3%) were random foods. The reproduction studies showed the spawning season extended within 2 peaks, from April- May and September and main spawning occurs in spring season.The mean absolute and relative fecundities were 472388±42633 and 3817±293 (X±SE), respectively. The maximum, minimum and mean of oocyte diameter were 0.448, 0.022 and 0.221mm (SE=0.071), respectively.The fork length at 50% maturity estimated to be 20.25 cm for females. The growth coefficient (K) , length infinity (L∞ ) and ɸ' was estimated 0.42/yr , 34.17 cm and 2.69, respectively. The coefficient of total mortality, fishing mortality, natural mortality and E was 1.37, 0.43, 0.94 and 0.31, respectively.
Resumo:
In order to come up with the responsible fishing pattern of common carp, there was a need to identify some of the biological characteristics and stock assessment of carp in Iranian waters of the Caspian Sea .The fork length ,weight ,age ,growth parameters of von bertalanffy and mortality rates of common carp were estimated from oct 2006 to sept 2007.Based on the exponential relationship between length and weight in the size range 6.3-65.6 cm ,b was calculated 2.895, 2.843 and 2.925 respectively for combined sexes ,males and females. The mean condition factor was 1.9 which is close to the ideal condition.The results from measuring 3170 specimens ,were showed the first fork length of maturity was 30 cm for males and 32 cm for females. The results indicated that females were predominate and sex ratio was 0.66:1 (M:F) and chi-squares analysis showeda significant difference between males and females.(p<0.05).Length infinity and growth coefficient were calculated by three different methods as below: Length frequency analysis : k=0.17 L∞ =68.04 Age-Length Key k=0.15 L∞ =74.25 Back calculation : k=0.14 L∞ =68.4 The mortality parameters and exploitation rate were estimated as below : Z=0.73 per year M=0.31 per year F=0.42 per year E=0.56 Refer to amount of common carp catch in 2007 -08 ,biomass was calculated 9640.2 tones by jone's cohort analysis and MSY 2374.5 tones.According to analysis ,the number of common carp in the distribution area (Iranian part of the Caspian Sea ) was estimated 24 millions in the 2006-07.
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Biological studies and heavy metal (Ni, v, Fe, Pb,Cd) determination in liver, gonad and muscle of Scomberomorus commerson were carried out from Oct 2006 to Sept 2007 in Hormozgan coastal waters. 599 Samples were gutted for reproduction and nutrition studies, fork length and weight were measured to nearest cm and g respectively. Meanwhile 40 samples were also investigated for heavy metal studies. All specimens were collected from two major landing sites (Bandar Lengeh & Bandar Abbas). Minimums & maximum fork length & weight were 29, 128 cm & 235 and 15350 g respectively.Isometric growth was shown according to our study and b was estimated 2.9 (overall), 2.91(male) & 2.89 (female). The average relative gut length was 0.52± 0.007 and it was determined that S. commerson is a carnivorous. More than 99 percent of gut content was different teleost fishes. Gastro somatic index had two peaks in Nov & Jan (before spawning) and with a decreased trend in July, the spawning period. Occurrence of empty stomach was estimated % 65.77. Maximum amount of condition factor was in Dec. Spawning season was started from June. The average of Absolute & relative fecundity (to weight unit) was 1217149±179315 and 178.2±15.58 respectively. Lm50% was estimated 75 cm for females. Sex ratio was 0.97: 1 (male: female). Chi- Square test showed no significant difference (p>0.05). Maximum amount of hepatosomatic index was estimated in March.Metal concentrations were determined using either Flame Atomic Absorption Spectroscopy (for Fe) or Graphite Furnace Atomic Absorption Spectroscopy (for Pb,Cd,Ni and V). The mean concentration (μg/g dry weight)of Pb,Cd,Ni,V and Fe in the liver were 0.0309, 0.0268, 0.0672, 0.0077, 2.5159 in the gonad 0.0440 ,0.0295, 0.1096, 0.0000, 1.4449 and in the muscle 0.0244, 0.0324, 0.0656, 0.0128, 1.6138 respectively. The maximum metal concentrations were below the maximum permissible limits for human consumption recommended by the USEPA, WHO and the UK. The results of Kendall's Tau-b correlation coefficient were as follows: The Liver tissue: There were significant positive linear relationships between accumulation of V, Fe, and Pb with Fork length, Pb and Fe with weight, GSI with Pb, Cd, V and 109 Fe, and a negative linear relationships between HSI with accumulation of V and Fe, Fork length, weight and GSI. The Gonad tissue: There were significant positive linear relationships between GSI with accumulation of Pb, Cd, Fe, Fork length and weight, a negative linear relationship between HSI with Fork length, weight and GSI. The Muscle tissue: There were significant positive linear relationships between accumulations of V, Fe with Fork length and weight factors and as well as GSI with Cd, V, Fe, Pb, Fork length and weight,a negative linear relationship between HSI with Fork length, weight, Cd, Fe and GSI. The results of Mann-Whitney U tests (P≤0.05) show that there were significant differences between summer and autumn from heavy metal contents in the studied tissues point of view. The only exceptions were for Ni in the liver, gonads and muscle and as well as there were significant differences between male and female from heavy metal contents in the studied tissues. The only exceptions were for Pb in muscle, Ni in liver, gonad and muscle, V in muscle, and Cd and Fe in gonads.
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The authors have attempted to compute the heat balance terms on the basis of formulas by Budyoko (1974). Some of the meteorological and oceanographic data were collected during the Trans Antarctic Expedition (1989-90). These data were supplemented by the data (1956-1988) made available by the national climatic center of NOAA (National Oceanic and Atmospheric Administration). Monthly means of sea surface temperature in Antarctic waters and meteorological data at a station (77°51'S; 166°39'E) 33m above sea level are given.
Resumo:
About 3600 specimens were collected by bottom trawl at 15 sampling stations. 24 biometric characters were measured for each specimens at the laboratory.. Microscopic cross – sections of statolith were used for age determination. Sex determination and fecundity were determined. Population dynamics parameters as well as stock as stock assessment including cohort analysis were estimated using FISAT software. The findings showed that Dorsal Mantle Length (DML) and Body weight (BW) of the Indian squid were 133.9 ± 0.78 mm and 99.61 ± 0.95 g respectively. Strong correlation was found between these 2 variables (R2 = 0.90). The maximum age was 5 years. Relationship between DML and age was highly significantly of p ≤ 0.05. Overall sex ratio (M: F = 0.52) was significantly different from the expected 1:1 ratio (p ≤ 0.05). The ovary weight and nidamental glands weight were 7.72 ± 0.0006 g and 3.07 ± 0.0003g respectively. Absolute and relative fecundity of the Indian squid were found to be 122733 ± 30.87 and 2348 ± 0.4 respectively. GSI were 14.35 in April and 8.63 in July. This squid is therefore a spring spawner. The infinite dorsal mantle length were 258.62 mm for females, 194.72 mm for males and 252.02 for both sexes respectively. For population growth and mortality parameters; K (0.65 per year for both sexes, 0.85 per year for males, 0.65 per year for females); t0 (0.24year for both sexes, 0.22 year in females, 0.26 year in male); φ` (2.30 in both sexes, 2.47 for males, 2.37 for females); Z (1.17 per year for both sexes, 1.10 per year in females, 1.39 per year, in males); M (0.70 per year for both sexes, 0.90 for males, 0.67 for females); F(0.27 per year for both sexes, 0.27 per year in males, 0.195 per year in females). Exploitation coefficient were 0.51 per year for both sexes, 0.57 per year males and 0.51 per year females respectively. The results indicates that since the Indian squid is a short live aquatic organism, therefore, the exploitation coefficient could be raised to 0.7 per year. The analysis showed that total biomass and MSY were 10103.5 ton and 2576.4 ton respectively. These findings are the first study of its sort about the Indian squid in the coastal waters of Oman Sea as well as North-West of Indian Ocean.