Recursos de colección

Aquatic Commons (41.069 recursos)

The Aquatic Commons is a thematic digital repository covering the natural marine, estuarine /brackish and fresh water environments . It includes all aspects of the science, technology, management and conservation of these environments, their organisms and resources, and the economic, sociological and legal aspects.

Subject = Conservation

Mostrando recursos 1 - 14 de 14

  1. Embryonic development and growth performances of an endangered fish species Nandus nandus: effects of dietary polyunsaturated fatty acids supplementation

    Rakhi, S.F.; Mohsinul Reza, A.H.M.; Shafaet Hossen, M.; Hossain, Z.
    The present study explored the embryonic and larval development of an endangered fish species Nandus nandus and resolved larval growth performances with the dietary supplementation of different types of lipids. Fertilized eggs were collected from fiber glass tanks immediately after spontaneous spawning of N. nandus, which were fed with a 1% phospholipid (squid meal) supplemented diet for 3 months. Fertilized eggs were transparent, spherical, yellowish and sticky in nature. The first cleavages of eggs were observed 0.3±0.01 h post fertilization at 26°C water temperature. Hatching started around 18 h post-fertilization and newly hatched larvae were found to be 1.2±0.1 mm...

  2. A comparative study of seasonal food and feeding habits of beardless barb, Cyclocheilichthys apogon (Valenciennes, 1842), in Temengor and Bersia Reservoirs, Malaysia

    Hamid, M.A.; Bagheri, S.; Nor, S.A.M.; Mansor, M.
    The food and feeding habit of beardless barb, Cyclocheilichthys apogon (Valenciennes, 1842), from family Cyprinidae was investigated by stomach content analyses of 374 collected fish in two consecutive reservoirs; Temengor and Bersia Reservoirs which are separated by Temengor Dam. The main aim of this study was to compare the stomach contents of C. apogon between these two reservoirs in wet and dry seasons. Results showed that C. apogon is omnivorous based on the moderate value of relative gut length. The main food items contained in their stomach were Oligochaeta, Chironomidae and detritus which made up over half of the stomach...

  3. Genetic analysis of six sterlet (Acipenser ruthenus) populations - recommendations for the plan of restitution in the Dniester River

    Fopp-Bayat, D.; Kuzniar, P.; Kolman, R.; Liszewski, T.; Kucinski, M.
    The aim of the present study was the genetic analysis of the Dniester population of sterlet Acipenser ruthenus and comparison of it to five other sterlet populations, in order to develop a population recovery plan. The genetic analysis of six sterlet populations from Eurasian rivers (Dniester, Dnieper, Danube, Volga, Kama and Ob) was carried out using microsatellite DNA markers. The genetic variation and genetic distance between studied populations were evaluated. Significant genetic differentiation was detected between the analyzed populations through the pairwise genetic differentiation index (Fst) test. The DA measure of genetic distance between pairs of populations indicated that the...

  4. Mixed milt fertilization of endangered Caspian brown trout Salmo trutta caspius influences effective population size of breeders

    Sourinejad, I.; Kalbassi, M.R.; Martinez, P.
    The maintenance of the endangered Caspian brown trout Salmo trutta caspius populations in Iran depends on its artificial breeding. There is no information on how current hatchery breeding protocol influences effective population size of breeders (Ne), which is a critical parameter to maintain genetic diversity in future generations. The current hatchery protocol (CHP) was comparatively evaluated with a balanced hatchery protocol (BHP), where mixtures of equal amounts of gametes per male and female breeder were used to balance parental contributions to progeny. To evaluate putative differences in viability between families, individual crosses were performed and fertilized ova of different families...

  5. Effects of diesel-oil spillage of fresh, brackish and marine waters on polyvinyl-alcohol (PVA) synthetic fishing twine

    Abdulsalami, S.A.; Akegbejo-Samsons, Y.; Odulate, D.O.; Arowolo, T.A.; Udolisa, R.E.K.
    The effects of diesel-oil spillage of fresh (0.4ppt), brackish (25ppt) and marine (37ppt) waters on elongation (cm) and breaking load (kgf) of artisanal PVA synthetic twine of varied diameter (4mm, 6mm, 8mm and 10mm) soaked for 16 weeks was studied. Chemical (solubility) test was carried out to identify the experimental twine as PVA among other synthetic twines. The elongation (cm) and breaking load (kgt) of PVA twine diameters were tested by tensile-strength gauge machine (0-200kg) and was carried out in unpolluted (control) and polluted states (spillage level) at 0%, 20%, 40%, 60%, 80% and 100% diesel-oil concentrations of different water...

  6. Aflatoxin levels in fish feeds in Abeokuta, Ogun State

    Akinyemi, A.A.; Adejola, A.; Obasa, S.O.; Munabau, O.K.
    Post harvest contamination can occur if drying of feed is delayed and when water is allowed to exceed critical values for mould to grow during storage. This study examined the aflatoxin levels in fish feeds surveyed in Abeokuta, Ogun State, Nigeria. Fifteen (15) fish farms were randomly selected for assessment of the aflatoxin levels in fish feeds in Abeokuta. After the estimation of the aflatoxin levels using Veratox quantitative aflatoxin test, the Aflatoxin concentrations in the samples ranged between 0-49 ppb with a mean value of 6.89 ppb. Results obtained from this study showed that aflatoxins were found to be...

  7. Adaptation strategy by fisher folks to climate change in Ogun State, Nigeria coastal fishing communities: implications for sustainable artisanal fisheries livelihood

    Fregene, B.T.
    The study examines the vulnerability and adaptation options of individual fishing households to climate change. Fourteen out of 24 fishing communities, with a total population of 20, 0000 artisanal marine fisher folks living on the 15 km coastal line in Ogun State, South West Nigeria were studied. Sources of data are Focus Group Discussion (FGD) with fisher-folks and questionnaires administered to 186 fishing households to assess vulnerabilities and methods of adaptation. The data were analyzed using descriptive statistics. Results of qualitative data reveal that the area is subjected to flooding due to storm surges during the rainy season months of...

  8. Management and utilization of water hyacinth (Eichhornia crassipes) for improved aquatic resources

    Sotolu, A.O.
    Natural aquatic plants population can be healthy for any aquatic ecosystems as they serve as fish feed, play an important role in nutrient cycling, purify the water, control unwanted algal growth and support fauna including birds. Water hyacinths (Eichhornia crassipes) have proven to be a persistent and expensive aquatic weed problem. The review was carried out in the face of current global challenge (climate change) which threatens biodiversity conservation and sustainable use of natural resources so that water hyacinth could be viewed as an asset of multifarious benefits considering the revealed highlights rather than been labeled expensive nuisance. The simplest...

  9. Coral relocation in Chabahar Bay, the North-east of Oman Sea

    Ajdari, D.; Motallebi, A. A.; Sharifrohani, M.; Sanjani, S.; Ajdari, Z.; Hajirezaee, S.; Zaiton Ibrahim, Z.
    Corals are marine benthic animals typically living in compact colonies of many identical individual polyps (Barnes, 1987; Gateno et al., 1996; Sumich, 1996). Coral reefs are important for many reasons including: a) Most importantly, they provide protection and shelter for many different species of fish. b) They turn surplus carbon dioxide in the water into a limestone shell. Without coral, the amount of carbon dioxide in the water would increase dramatically and that would affect all living things on Earth. c) Similar to a barrier, the coral reefs protect coasts from strong currents and waves by slowing down the water...

  10. Genetic analysis of wild common carp, Cyprinus carpio L. in the Anzali wetland, the Caspian Sea

    Fallahbagheri, F.; Dorafshan, S.; Pourkazemi, M.; Keivany, Y.; Chakmedouz Qasemi, F.
    The Caspian Sea and its basin (e.g. Anzali wetland) is one of the natural habitats of wild common carp Cyprinus carpio. In this study the genetic structure of this species in the south-west of Caspian Sea (the Anzali wetland) was investigated using PCR-RFLP analysis of D-loop region. Two hundred of mature fish were collected from 5 stations (40 individuals from each station) including Siahkeshim protected area (SK), Selke wild refuge (S), Sorkhankol wild refuge (SO), Abkenar (A) and the Anzali wetland estuary (E) during spawning season. A 420bp fragment of D-loop was amplified and the PCR products were digested with...

  11. Marine protected areas and the benefits of their establishment

    Francis, A.; Zabbey, N.
    Marine Protected Areas (MPAs), conservation and fisheries management tool, come in various sizes and shapes, and fulfill various purposes. They pre established for purposes of protection, restoration and preservation of' biota, ecosystem and ecological processes, and include recreational, educational and cultural purposes. Steps in the establishment of MPAs, their benefits and effectiveness have been highlighted. Current and profitable trends as seen in the establishment of Network of MPAs have been reported also. It has been noted that there is much benefit in using MPAs as management and conservation tool for natural aquatic resources, yet less areas have been demarcated for...

  12. Case studies on HIV/AIDS in fisheries development: lessons for Nigerian fisheries

    Olowosegun, T.; Ovie, S.I.; Sanni, O.A.; Sule, A.M.; Bwala, R.I.; Olowosegun, O.M.
    This paper reviews accounts of social and economic features of HIV/AIDS epidemics in the fisheries sector focussing on Africa with particular reference to Nigeria. Fishing communities are often among the highest-risk group, with high overall rates of HIV/ AIDS prevalence. It is more important to use the information made available from these efforts in more effective way of targeting the appropriate interventions and measures that can be designed and instituted. This information could also serve useful purposes and the efficient mobilization of needed resources from all possible sources in order to achieve the Millennium Development Goals in the Fisheries sector...

  13. Fisheries and ecotourism: a tool for national development

    Moses, B.S.
    The paper which is a key note address, examined the concept of the United Nations Conference on Environment and Development (UNCED) held in Rio de Janeiro (Brazil), June 1992 as it relates to fisheries and land based tourism. The significance of fisheries to the world economy and the trends in global fisheries production are highlighted. The world production is put at 130.8 million tonnes, while production in Nigeria is put at 408.9 tonnes. The relationship between fisheries and ecotourism are discussed. Advantages in co-developiong fisheries and ecotourism are highligthed.

  14. Public health implications of Gurara River around Izom environs, Niger State, Nigeria

    Adama, S.B.; Kolo, R.J.
    Water samples were collected from River Gurara around the Gurara Falls and Izom settlement once every month for a period of twelve (12) months (June 2004 May 2005). Microbial studies were carried out on the water samples collected. There were marked variations between different samples, stations and seasons. The microbial studies showed the presence of enteric gram negative, gram positive and pyogeric groups of bacteria. Some species of indicator organisms were recorded. The results obtained showed that the activities of Izom populace has some impact on the water quality and public health status of River Gurara

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