The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square met...The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square metre belt transects along each permanent line transect at 20 metre intervals were used to collect data. The data were subjected to univariate and multivariate analyses. Spatial variations of epibenthic echinoderm abundance were assessed with one-way analysis of variance. Hierarchical agglomerative clustering was used to identify and illustrate the similarities in echinoderm abundance between line transects and between belt transects. Indices of richness (d), diversity (H'), evenness (J') and dominance (C) were used to explain the diversity of epibenthic echinoderm species. The distribution pattern of each echinoderm species was determined in each permanent line transect. A total of 986 individuals were recorded within sixteen species of epibenthic echinoderms in the four line transects. Holothuriidae was the dominant family (5 species and 342 individuals). The most abundant echinoderms species was Pearsonothuria graeffei (77 individuals, about 7.81%). Abundances intra-transects and intra-families were insignificant (f = 1.67, p = 0.183, df = 3 and f = 3.24, p = 0.083, df = 9, respectively). The highest values of Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef species richness index (d), and Simpson Dominance index (C) were 2.738, 0.9875, 2.791 and 0.07159, respectively. The distribution patterns of all species in the study transects varied between clumped and uniform, with the exception of Asthenosoma varium of the Echinothuridae family, which had clumped distribution patterns in all transects. The study concluded that Dungonab Bay supports rich and diverse communities of epibenthic echinoderms.展开更多
Socio-economic characteristics related to fishing gears and boats from three selected small-scale fishers’ communities (Oseif, Dungonab and Mohammed Qol) in the northern part of the Sudanese Red Sea coast were studie...Socio-economic characteristics related to fishing gears and boats from three selected small-scale fishers’ communities (Oseif, Dungonab and Mohammed Qol) in the northern part of the Sudanese Red Sea coast were studied. The study was designed to provide base line data and information on the current socio-economic situation, factors that determine the use of fishing gear, types of boats and fishing equipment, challenges facing fishers and the extent to which fishing gear and boats are related with the socio-economic characteristics of the fishers community in the study sites. Fieldwork was carried out during 2016. The study methods included a series of interviews based on questionnaires, field observations and focus group discussions. The results of the study showed that the most common fishing gears are handlines, cast nets and gillnets. The two types of boats used at the study sites are motorized fiberglass and houri (motorized and paddled) with a V-shaped hull. Boat ownership varies among fishers. Each fisher can have several types of gears in different numbers. Target fish species, season, efficiency of gear and fishing location were the main factors determining the use of fishing gear at study sites, respectively. All fishers are men and most have families of at least four people. The majority of fishers are between 21 and 50 years old and work mainly in fishing. They inherited fishing knowledge within the family, and most of them have been working in artisanal fishing for more than 10 years. Fishers have relatively good net incomes compared to other government employers in the study sites. Most fishers work full time in fishing. A small number of fishers work part-time with the possibility of undertaking other income-generating activities such as animal husbandry and seasonal agriculture. The main challenges identified by fishers at the study sites were fish prices, sea surface roughness and high cost of fishing materials, respectively. Most fishers perceived a recent decline in both catch size and abundance.展开更多
A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed fo...A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed for effective identification and quantitative determination of the two compounds simultaneously when Δλ=60 nm is chosen.The linear ranges for Sudan Ⅱ and Sudan Ⅲ were 0—3.3 and 0—2.8 μg/mL,respectively.The detection limits for Sudan Ⅱ and Sudan Ⅲ were 14 and 11 ng/mL,respectively.By using this method,Sudan Ⅱand Ⅲ in sausage samples were determined directly with the recoveries of 83.8%—109.5%.展开更多
文摘The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square metre belt transects along each permanent line transect at 20 metre intervals were used to collect data. The data were subjected to univariate and multivariate analyses. Spatial variations of epibenthic echinoderm abundance were assessed with one-way analysis of variance. Hierarchical agglomerative clustering was used to identify and illustrate the similarities in echinoderm abundance between line transects and between belt transects. Indices of richness (d), diversity (H'), evenness (J') and dominance (C) were used to explain the diversity of epibenthic echinoderm species. The distribution pattern of each echinoderm species was determined in each permanent line transect. A total of 986 individuals were recorded within sixteen species of epibenthic echinoderms in the four line transects. Holothuriidae was the dominant family (5 species and 342 individuals). The most abundant echinoderms species was Pearsonothuria graeffei (77 individuals, about 7.81%). Abundances intra-transects and intra-families were insignificant (f = 1.67, p = 0.183, df = 3 and f = 3.24, p = 0.083, df = 9, respectively). The highest values of Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef species richness index (d), and Simpson Dominance index (C) were 2.738, 0.9875, 2.791 and 0.07159, respectively. The distribution patterns of all species in the study transects varied between clumped and uniform, with the exception of Asthenosoma varium of the Echinothuridae family, which had clumped distribution patterns in all transects. The study concluded that Dungonab Bay supports rich and diverse communities of epibenthic echinoderms.
文摘Socio-economic characteristics related to fishing gears and boats from three selected small-scale fishers’ communities (Oseif, Dungonab and Mohammed Qol) in the northern part of the Sudanese Red Sea coast were studied. The study was designed to provide base line data and information on the current socio-economic situation, factors that determine the use of fishing gear, types of boats and fishing equipment, challenges facing fishers and the extent to which fishing gear and boats are related with the socio-economic characteristics of the fishers community in the study sites. Fieldwork was carried out during 2016. The study methods included a series of interviews based on questionnaires, field observations and focus group discussions. The results of the study showed that the most common fishing gears are handlines, cast nets and gillnets. The two types of boats used at the study sites are motorized fiberglass and houri (motorized and paddled) with a V-shaped hull. Boat ownership varies among fishers. Each fisher can have several types of gears in different numbers. Target fish species, season, efficiency of gear and fishing location were the main factors determining the use of fishing gear at study sites, respectively. All fishers are men and most have families of at least four people. The majority of fishers are between 21 and 50 years old and work mainly in fishing. They inherited fishing knowledge within the family, and most of them have been working in artisanal fishing for more than 10 years. Fishers have relatively good net incomes compared to other government employers in the study sites. Most fishers work full time in fishing. A small number of fishers work part-time with the possibility of undertaking other income-generating activities such as animal husbandry and seasonal agriculture. The main challenges identified by fishers at the study sites were fish prices, sea surface roughness and high cost of fishing materials, respectively. Most fishers perceived a recent decline in both catch size and abundance.
文摘A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed for effective identification and quantitative determination of the two compounds simultaneously when Δλ=60 nm is chosen.The linear ranges for Sudan Ⅱ and Sudan Ⅲ were 0—3.3 and 0—2.8 μg/mL,respectively.The detection limits for Sudan Ⅱ and Sudan Ⅲ were 14 and 11 ng/mL,respectively.By using this method,Sudan Ⅱand Ⅲ in sausage samples were determined directly with the recoveries of 83.8%—109.5%.
