Aquatic Commons
Not a member yet
22986 research outputs found
Sort by
Survey on ecological characteristicsof Horolazim wetland in Khouzestan (2012-2013)
Get PDFRregarding the potential and capabilities of different socio-economic, ecological and recreational, Hurolazim wetland is allocated as a special place in the collection of ecosystems and environment and the study of existing ecological conditions is necessary to protect and restoring management. In this study, monthly Samples of four stations (stations north of the road, Imam Reza (1) and south of the road, Imam Reza (2), in the Rofayeh area and stations Tabor (3) and the Shatt Ali (4), in the Shatt Ali area) were taken during the year from April to March 2012. Samples included physical and chemical parameters, phyto and zoo planktons, benthos, fish, and fishing status. Phytoplankton samples using sampling bottles from 0.5 meters below the surface were taken and counted based on alive unit. Zooplankton samples were collected by 100 micron mesh size plankton net from a depth of 1.5-2 meters. Benthic animals and sediment were sampled by Van Vin grab(0.125 square meters). One sample for benthos and one sample for grain size analysis and percentage of organic matter were sampled from each stations. In order to estimate the monthly depleted catches, data collected from the census in place and sampling was done at the time. Three fishing area has inspected randomly once every 15 days and active fishermen and caches were recorded in the prepared forms during the day. In this way, the number of observed boats, the average boat per day, the catches of the boats and CPUE were registered and total fishing effort was calculated monthly. In this study, 194 species of phytoplankton were identified. Diatoms with 85 species, Cyanophyta with 59 species, Chlorophyta with 31 species, Euglenophyta and Dinophyta with 18 and one species were observed respectively. The highest abundance frequency of phytoplanktons with 38.96 percent were observed in Tabar station (3), Diatoms with 46% has shown the highest frequency and then Cyanophyta (34.17%), Chlorophyta (16.39%), Euglenophyta (1.6 %) and Dinophta (1.58%) were included of the total abundance respectively. In the summer colonies of Cyanophyta were in high density. A total of 35 species of zooplankton have been identified. from Rizopoda, the species of Arcellidae and Centripyxidae families, from Rotifera, the species of Brachionidae, Lecanidae, Asplanchnidae and Philodinidae families, from Cladocera ,the species of Daphnidae, Sisidae and Chydoridae families and from copepods, Cyclopoda families have been observed that included about 98 percent of identified zooplankton. Respectively, Copepoda (39.9 %), Rotifera (34.71 %), Cladocera (22.38 %) and Rizopoda (0.843 %) were dominant groups. The species Brachionus urceolaris with average density of 7.29 individual per liter, is the most abundant species that included 17 % of total abundance frequency in the wetland. The higher frequency of crustacean zooplankton such as Copepoda and Cladocera could be indicated an environment more favorable conditions and expected to be good status of food in the Horolazim wetland. Among the known benthic groups, families, Tephritidae (85%) and Chironomidae (7 %) of the order Diptera and Ostracoda (2 %) from crustacean, were the dominant macrobentic groups Among the studied stations, Station South Road Imam Reza (2), and the station Shatt Ali (4), were the highest and the lowest abundance respectively. The mean abundance of macrobenthos in different seasons showed the lowest and the highest abundance frequency in summer and winter respectively. According to diversity indices, The stations Tabar (3) was the highest and the Station South Road Imam Reza (2), was the lowest value of diversity index. The results showed the higher than 71.84 % of Silt-Clay percentage in all stations, The highest value of sediments TOM in the Station South of the Road Imam Reza(2) in the winter and the lowest in station Shat Ali(4) in summer were recorded. Based on HFBI index the stations north of the road Imam Reza (1) and the station Shatt Ali (4) in moderate status and the stations south of the road Imam Reza (2) and Tabar (3) in good status were classified. In this study, 15 species of fishes belonging to 8 genera and 3 families were identified. It was noticed that 87.4 percent of all identified species in the wetland belonged to the Cyprinidae family. The results of previous studies in 2006 and 2008 in the Iraqi part of Hawizeh wetland showed that the most common fish species belonged to Biah, Karas, Hemry and Shelej that included 89.3 percent of total fishing in the current study .Finally, It is evaluated that changes in water regime of freshwater wetlands, controlled the environmental characteristics and conditions. That means water plays a decisive role in the vital characteristics of wetlands. Changes of quantity and quality of water may be associated with changing the quantity and quality of biotic fauna in wetland system. In the management and protection of a wetland system, it is necessary to adopt measures based on scientific principles and reasonable methods in order to protect water quality
Effects of seawater pH on survival, growth, energy budget and oxidative stress parameters of juvenile turbot Scophthalmus maximus
Get PDFThis study aimed to elucidate the influence of environment pH on survival, growth, energy allocation and oxidative damage of juvenile Scophthalmus maximus (19.89±0.25 g). Six pH treatments (6.3±0.2, 6.8±0.2, 7.3±0.2, 7.8±0.2, 8.3±0.2, 8.8±0.2) lasting for eight weeks were included. Measurements of survival (SR), feed conversion ratio (FCR), specific growth rate (SGR), weight gain rate (WGR), energy allocation, liver superoxide dismutase activity (SOD), catalase activity (CAT), and malondialdehyde concentration (MDA) were done. Results show that SR did not vary from pH 6.3 to 7.8, but reduced then significantly (p0.05). CAT kept stable between pH 6.3 and 7.3, then sharply increased (p0.05). Subsequent decrease in MDA was found from pH 6.3 to 8.3 then the concentration smoothly increased. Overall, our results indicate that a pH in the range of 6.8 to 7.8 is recommended in the growth environment in cultivation of juvenile turbot
Agua y Humedales
Get PDFEste libro contiene las presentaciones de las conferencias invitadas de expertos y las realizadas en formato “poster” por los estudiantes participantes en el Workshop “Aguas + Humedales”, realizado en San Martín entre el 17 y el 22 de octubre de 2016 en la Universidad Nacional de San Martín, San Martín, Argentina.
Con el objeto de brindar a los estudiantes de posgrado un panorama amplio del problema del agua y su proyección hacia el futuro, el material que aquí se presenta se ocupa de temas tales como el agua como fuente segura para consumo humano y su vida cotidiana, como recurso fundamental para la actividad agropecuaria, como fuente de alimentos, como fluido de proceso y de transporte de calor, como vía de comunicación y transporte. Se plantean interrogantes sobre la disponibilidad del recurso, sobre la intervención humana en el ciclo hidrológico y en el clima. También se analizan problemas relacionados con tecnologías para el tratamiento de aguas, tanto para consumo humano como tratamiento de efluentes de diverso tipo. Se presta especial atención a la dimensión social del tema: derecho y economía del agua, estudios vinculados con las decisiones sobre el uso del recurso y el desarrollo de legislaciones y regulaciones
India: natural hazards, in the eye of the storm
Get PDFIn the wake of tropical cyclone Ockhi, the focus now should be on improving at-sea cyclone preparedness and search-and-rescue co-ordination to save precious live
Southeast Asia: recognize tenure rights
Get PDFFormal recognition of marine tenure provides an incentive for small-scale fishers to form and support the overarching structure for responsible governanc
Indonesia: SSF, strong pillars
Get PDFThe fisheries and coastal resources policy of Indonesia requires a specific operational and regulatory framework to ensure the the protection of traditional small-scale fisher
Women rising: a critical look at Towards gender-equitable small-scale fisheries governance and development: a handbook by Nilanjana Biswas
Get PDFA critical look at Towards Gender-equitable Small-scale fisheries Governance and Development: A Handbook by Nilanjana Biswas, published by the FAO, in 201
Inland valley swamp assessment in Tonkolili District, Sierra Leone
Get PDFInland valley swamps (IVSs) form part of the upland-inland valley continuum in Sierra Leone, occupying the lowest position in the landscape. This study aimed to analyze the actual use, constraints on the use and the agro-potential of IVS in Tonkolili District. Through interviews and limited field testing, it was possible to obtain detailed information regarding socioeconomic aspects and food production systems, as well as a rough assessment of physical properties such as soil quality and inundation period for each targeted IVS in all 11 chiefdoms in the district. The report concludes with several recommendations for interventions to optimize the use of IVSs in Tonkolili District to enhance food production, nutrition and income
Trophic level, food preference and feeding ecology of Rachycentron canadum (Linnaeus, 1766), in Hormuzgan Province waters (northern Persian Gulf and Oman Sea)
Get PDFThis study examined the ecological factors associated with feeding in Rachycentron canadum (cobia) in the waters of Persian Gulf and Oman Sea. Seasonally variation of stomach condition of cobia male, females, pooled and size wise were analyzed. In general, 577 cobia were collected (340 males, 237 females) (20–161 cm Total length) from Sept. 2014 to Sept. 2015 by the Ferdows-1 survey ship and from the landing areas in Bandar Abbas harbor seasonally. Our results provide the first estimates of trophic level (Tr.L) (4.32±0.76, mean±Se), consumption per biomass (Q/B) (6.13), and aspect ratio of the caudal fin (ARc.f) (3.1) for R. canadum in the Hormuzgan Province. We also found that bony fish made up more than 80 percent of the relative importance of particular prey (IRI %), indicating R. canadum primarily preys on these species. The immature group (20–40 cm, T.L), tended to feed on Penaeidae family, small crabs, and mollusks. Hierarchical clustering revealed that the frequencies of different types of prey could be applied to categorize the length classes into three levels. The result of this study revealed that the immature group and the 20-40 cm length class tended to feed on Penaeidae family, crabs, and mollusks. Also, we found that males generally fed more than females in all seasons and that R. canadum had an average dietary intake. The findings of this study can be used to prepare a food formulation for cobia that resembles the native diet