•Red blood fatty acid profile of Omani pre-adolescent school children was investigated before and after intervention with oily fish or DHA enriched fish oil capsules for twelve weeks.•Seafood is an ...integral part of Omani traditional diet but the children had a low level of n-3 fatty acid index at baseline.•There was no gender related difference in EPA, DHA or AA at baseline.•Both oily fish and fish oil capsules increased the level of red blood cell n-3 fatty acid index.•Red blood cell n-3 fatty acid index correlated positively with AA and inversely with total saturated and total mono-unsaturated fatty acids in the oily fish and fish oil groups.
Dietary habits of Omani population particularly of children and young adults have changed significantly. Consumption of imported calorie-dense foods, vegetable oils, milled and polished grains and carbonated beverages have become the norm. Concomitantly, there has been an exponential increase in the prevalence of non-communicable diseases. The impact of the westernisation of eating habits on children has not been evaluated. We have investigated blood fatty acid profile of male (n = 125) and female (n = 160) children aged 9 and 10 (9.8 ± 0.4) years enrolled from three state-funded schools. The schools, which are homogenous with respect to socio-economic background of their pupils, were randomised into fish oil (n = 98), oily fish (n = 82) or control (n = 105) group. Subsequently, the children were given during morning tea break for 12 weeks: 1. DHA-enriched re-esterified triacylglycerol fish oil capsule with cheese/salad sandwich (fish oil group), 2. Lightly grilled oily fish with salad (fish group) or 3. Cheese/salad sandwich (control group). At baseline, the males had higher myristic, palmitic and oleic and lower adrenic acids than the females (p < 0.05). There was no difference in n-3 fatty acid index (4.86 ± 1.95 vs. 5.12 ± 1.67, p > 0.05) or AA (14.6 ± 1.9 vs. 14.9 ± 1.8, p > 0.05) between the genders. There was no difference in any of the fatty acids between the three groups at baseline. Post-intervention, the oily fish group had lower n-3 fatty acid index (EPA + DHA, 6.03 ± 1.39 vs. 6.60 ± 1.63, p < 0.05) and higher AA (15.2 ± 1.8 vs. 13.7 ± 2.0, p = 0.0001) and n-3 DPA (1.40 ± 0.27 vs. 1.07 ± 0.22, p = 0.0001) compared with those who received fish oil capsules. In both the fish oil and oily fish groups, fatty acid index correlated positively with AA (r = 0.394, p = 0.0001; r = 0.231, p = 0.038) and negatively with total saturated (r = - 0.816, p = 0.0001; r = - 0.439, p = 0.0001) and total mono-unsaturated (r = - 0.431, p = 0.0001; r = - 0.231, p = 0.037) fatty acids. Although seafood is an integral part of traditional Omani cuisine the children had a low level of n-3 fatty acids index. There is a need to address this nutritional insufficiency through school feeding programme, targeted intervention with n-3 fatty acid enriched food products and/or family education programme.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Interdecadal changes in oxygen depletion, with a special reference to artisanal landings of large pelagic fishes, were analysed. Data from 53 expeditions incorporating 29,043 vertical profiles of ...temperature and 2114 of dissolved oxygen implied an increase in temperature of 1.2 °C over the past 50 years in the upper 30 m layer of sea water during the south-west (summer) monsoon. The thermal stratification of the water column increased and the oxycline shoaled from 153 m in the 1960s to 80 m in the 2000s. Concentration of dissolved oxygen <3.5 mL L
−1
is known to induce symptoms of stress for many tropical pelagic fishes, compressing them within upper layers and exposing them to fishery. The habitat compression by the Oman shelf hypoxia has two components: a seasonal oxycline shoaling and an interdecadal trend.
Full text
Available for:
BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
Female Rhizoprionodon acutus were found to mature between 62 and 74 cm total length (LT) whereas males matured between 63 and 71 cm LT. The LT at 50% maturity was 64·3 cm for females and 64·7 cm for ...males. Litter size varied from one to six embryos, and was positively correlated with maternal LT. Female embryos outnumbered males by a ratio of 2·3:1. The size at birth was c. 37 cm LT. Full‐term embryos and post‐partum females were observed during all seasons although their occurrence was highest in spring. Spermatozoa were rarely recorded in the oviducal gland, indicating that this species does not store sperm. It was not possible to generate maturity curves for Iago omanensis but it was evident that females matured by the time they reached 35 cm and males were mature by 31 cm LT. This species displayed a clearly defined reproductive cycle with parturition occurring primarily in spring, after a gestation period of c. 1 year. Maximal embryo size was 19 cm LT while maximal litter size was 24 embryos. The oviducal gland appeared to act as a seminal receptacle and it appeared that females may utilize these stores by not mating every year.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Patterns of reproduction and spawning were determined for the kingfish (
Scomberomorus commerson, Lacépède) in two oceanographic regions of the Sultanate of Oman. During 2 years of sampling, 1264 ...fish were purchased from fishermen at landing sites along the Arabian Sea and the Gulf of Oman. Sizes of males and females were similar in both regions but more females were caught along the Gulf of Oman than along the Arabian Sea coast. Females matured at a significantly smaller length and about 2 months earlier than males in both regions. For both sexes, the fish collected along the Arabian Sea matured approximately 10
cm smaller and 6 months earlier that those of the Gulf of Oman. Analysis of the reproductive stages and gonosomatic index revealed a single yearly reproductive cycle beginning in February and ending with a single spawning period in May–June, just prior to the onset of the summer oceanographic regime. Reproductive stages and growth also indicated that 40% of the landings along the Arabian Sea is composed of fish before their first reproduction (Stage I) whereas along the Gulf of Oman, only 25% of the fish were caught before entering active reproduction. Several indicators suggest that kingfish stocks are under intense pressure and that management of this species should be implemented rapidly if they are to remain sustainable.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Age and growth parameters were determined for the kingfish (
Scomberomorus commerson) at six locations in the Sultanate of Oman. During 2 years of sampling, 1244 kingfish were collected, from which ...962 sagittal otoliths were sectioned and read. The fishery is characterized by a prevalence of 0+, 1+ and 2+ year classes, which made up approximately 90% of the total fish collected. Maximum fork lengths, weights and ages for all sexes combined were 166
cm, 40.4
kg and 20 years, respectively. Sex specific differences were evident in length, weight and growth. Growth parameters show that female
S. commerson (
L
∞
=
140.44,
K
=
0.309,
t
0
=
−1.501) grew at a slower rate but reached a greater asymptotic length than male fish (
L
∞
=
118.80,
K
=
0.595,
t
0
=
−0.730). There were significant differences in growth between regions with Ash-Sharqiyah recording the greatest asymptotic length (
L
∞
=
172.82) and Al-Wusta the lowest (
L
∞
=
122.596). Fish from Al-Wusta also grew at a much greater rate (
K
=
0.796) than those from the other five regions. A comparison of VBGF values using length frequency data and age at length data at one region, Muscat, revealed differences in all three growth parameters. Catch curves reveal large differences in total mortality (
Z) between geographic regions, with the highest recorded at Al-Batinah (1.321
year
−1) compared with 0.405
year
−1 at Muscat. Large discrepancies in age structure, growth parameters and annual mortality between regions suggest overexploitation of this species may have already occurred in places like Al-Batinah and Dhofar. However we recommend that mortality estimates (
Z,
M and
F) be used with caution until catch curve data for different fishing gear is made available.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Sultanate of Oman has a long established traditional shark fishery, which has experienced increased demand in recent years due to the shark fin trade. Despite the long history of the fishery in ...Oman and neighbouring countries, few studies have been undertaken to determine the biological characteristics of the fishery or its ability to withstand this increased exploitation. The present study was undertaken as a first step to remedying this situation. A total of 47 species was confirmed from Oman's coastal waters, of which 44 occurred in commercial landings. However, landings were dominated by eight species—
Rhizoprionodon acutus,
Iago omanensis,
Carcharhinus sorrah,
Loxodon macrorhinus,
C. macloti,
C. limbatus,
Sphyrna lewini and
C. falciformis. The species composition of landings varied along the coast and also with season. Brillouin Index values indicated that species diversity was greatest in the Muscat area, followed closely by Musandam. The Al-Wusta region displayed the lowest diversity. The occurrence of two uncommon shark species,
Chaenogaleus macrostoma and
Echinorhinus brucus, was of interest, as was the recording of a juvenile
Carcharhinus galapagensis, extending its northern range in the Indian Ocean considerably.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Summary
The spawning periods, sex ratio and length at first maturity were determined for six commercially important finfish species collected from Oman's industrial trawl fishery. During 1 year of ...monthly sampling, biological data were collected on 5586 fish. ancova was used to compare the length–weight relationships between sexes. There were sex‐specific differences in length‐weight relationships for three of the six species examined. One serranid, Epinephelus diacanthus, and a sparid, Pagellus affinis, had sex ratios significantly different from the expected ratio of 1 : 1. Size–frequency data revealed more male fish in the larger size classes for E. diacanthus, P. affinis and Nemipterus japonicus. Data on the development of female gonads and Gonado‐somatic Index (GSI) revealed that the six species spawned at different times of the year. With the exception of female E. diacanthus, all fish had low GSI values during the onset of the summer monsoon period in June. The proportion of immature vs mature fish in the sample differed among species. For two species, Lethrinus nebulosus and Cheimerius nufar, more than 40% of the fish sampled (both sexes) were immature. Approximately 33% female and 41% male P. affinis were also immature. Management options such as temporal and area closures are discussed in light of the large number of immature fish caught by the fishery.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Oman's fishery resources are exploited by artisanal and industrial fisheries, but the former accounts for almost 90% of landings. Within the artisanal fishery, sharks have traditionally been ...harvested for their flesh, but the development of a valuable export market for shark fin has led to increased utilisation of this resource, and anecdotal information suggests that shark abundance has decreased in recent years. Whereas management of the shark fishery is desirable, the biological and socio-economical data on which to base any management plan are lacking. The present study was undertaken to collect size frequency and sex ratio information from the shark species most commonly encountered in the artisanal landings, namely Carcharhinus falciformis, C. limbatus, C. macloti, C. sorrah, lago omanensis, Loxodon macrorhinus, Rhizoprionodon acutus and Sphyrna lewini. The occurrence of large female sharks in the landings, combined with a high proportion of juveniles of certain species, suggests that species-specific size restrictions should be considered in any management plan for Oman's shark fishery.
Full text
Available for:
BFBNIB, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•PV-electrolysis demonstration using concentrated and non-concentrated PV modules.•STH of 18-21% = 0.8-1.0 LH2/(min.m2PV area) is obtained using concentrated PV.•STH of ~9.5% = 0.3 LH2/(min.m2PV ...area) is obtained using Si-based-PV without tracker.•• Conc. PV-Electrolysis is poised to compete with Si-based-PV in the near future.
We report outdoor experimental results of PV-electrolysis systems using a series of proton exchange membrane (PEM) electrolyzers powered directly either through InGaP/GaAs/Ge based concentrated (750 sun) or Si based non-concentrated (1 sun) PV modules. At power matched conditions, solar to hydrogen (STH) conversion efficiency of 18–21% with a production rate of 0.8–1.0 L/(min-m2module area) of H2 was obtained using concentrated PV modules (~28–30% efficiency). Conventional Si module (~17.5% efficiency), on the other hand, generated about 0.3 L/(min-m2module area) of H2 Average with a STH Average of 9.4%. While scaling up of the electrolyzers by increasing the size of their electrodes resulted in a similar voltage losses due to mismatching of their power point with that of PV modules (when coupled without power electronics), scaling them out in series maximizes H2 production by utilizing the maximum power available from PV. Unlike, PV-electrolysis operated via power electronics, direct integration of PV modules with electrolyzers leads to effective utilization of PV power, with STH values closer to the theoretical limit of the coupled system (STH = PV module efficiency × Electrolyzer efficiency). The H2 production rate and STH using a concentrated system with a solar tracker remained constant and high during the measurement period (5–6 h). On the other hand, the production rate as well as STH varied with time on a conventional Si module without a tracker under 1 sun, with a significantly low average H2 production rate. Keeping cost factor aside, PV-electrolysis under concentration outweighs the performance of non-concentrated PV based system by a factor between 1.5 and 3.0.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Probing into the relationship between charge carrier dynamics and photocatalytic reactions is central to the understanding and therefore the design of photocatalysts. We have studied the charge ...carrier lifetime of Pt/C3N4 and compared it to that of C3N4 alone using femtosecond pump–probe transient absorption spectroscopy in the 500–900 nm signal range. Parallel photocatalytic reactions were also conducted to link the extracted lifetime to the corresponding rates of hydrogen production from water. The presence of Pt (with a mean particle size of ca. 2.5 nm) on C3N4 decreased the lifetime of excited electrons in the conduction band (CB). This has occurred in pure water as well as in the presence of the organic sacrificial agent used. These results suggest that Pt particles on this n-type semiconductor act as electron trap centers (either by pumping away CB electrons or by creating trap centers at the interface). The corresponding increase in reaction rates can be linked to this electron transfer.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
PDF
