Aquatic Commons: No conditions. Results ordered -Date Deposited. 2020-11-16T01:50:42Z EPrints 22875 20 1 2020-11-12T05:14:11Z 2020-11-12T05:14:11Z This item is in the repository with the URL:
2020-11-12T05:14:11Z Benthic assemblages for ecological evaluation of Bardawil Lagoon, Mediterranean Sea, Egypt Bardawil Lagoon is the only highly saline oligotrophic lagoon in Egypt, has an area of ca. 650 km2 with water depths ranged 0.3m to 3m and economically important in terms of fish production. It is the optimum zone getting migratory birds in winter. It is separated from the Mediterranean Sea by a narrow sandy shelf (90 km length, and 22 km width). Ecological evaluation of benthic communities in Bardawil Lagoon to follow-up study of the distribution of benthic study at 12 selected sampling sites representing different environmental habitats for long periods through the project of Environmental Study Wetlands OF North Egyptians Lakes where samples were collected seasonally (2010-2015) and semi-annually (2015 - 2019). The results and data analysis indicated that the distribution, composition and dominance of macro benthic organisms in Lake Bardawil were composed mainly of Ostracoda, Polychaeta, Sea grasses, Bivalvia, Insecta larvae communities and dominated the constituent of bottom fauna. The variations in the benthic biomass were the heaviest at sites elRaodh and meddle elRaodh representing 1354 and 1105 g/m2 which corresponding respectively to 18.2 % and 14.9% of the annual average of benthic biomass (619 g/m2). Regional variations abundance of the benthic structure was highest at sites elTelol and elRaodh representing 3486 ind/m2 and 3635 ind/m2 which corresponding respectively to 14.8% and 15.3% of the annual average of benthic density (1978 ind/m2). Sites of sampling study were evenly spread (J’ > 0.8) at most sites except at elTelol and elRaodh also, high diversity (H’ > 3.00) was at the most sites and show lower value at sites elTelol, elGals, Boughaz I, elNaser, and Raba`a while, Swartz Dominance indexes of number of 5 species over 75% showed low values at sites elGals, Boughaz I, elNaser, and Raba`a. The abiotic environmental effects in the Bardawil Lagoon are general to those generally observed in other areas influenced by organic wastes, namely, changed in the physic-chemical properties of the sediments and low oxygen concentrations in the bottom water due to decomposition of organic materials. Mohamed Mohamed El komi
2020-11-12T05:12:13Z 2020-11-12T05:12:13Z This item is in the repository with the URL:
2020-11-12T05:12:13Z Artificial neural networks model biometric features of marine fish sand smelt In this study was investigated some biometric properties of the sand smelt with ANN’s, Atherina boyeri Risso, 1810, population in Yamula Dam Lake. Twenty-three morphometric characters of samples were measured. The total length of individuals which were caught between 6.40 and 10.20 cm, and their weight (W) were ranged between 1.50 and 7.31 g. The effect of Artificial Neural Networks was investigated in predicting the statistical of fishery industry. The present study provides the first information on the biometric properties of Atherina boyeri in Yamula Dam Lake by Artificial Neural Networks. Semra Benzer Recep Benzer
2020-11-12T05:04:53Z 2020-11-12T05:04:53Z This item is in the repository with the URL:
2020-11-12T05:04:53Z Empirical use of growth, mortality and temperature data for anchovy To estimate the empirical relationships in anchovy, the instantaneous natural mortality rate (M) calculated from von Bertalanffy Growth Function (VBGF) parameters, maximum total length (Lmax) and sea surface temperature (T,°C) were reviewed in the Black Sea. Empirical equations were presented for evaluation of M data in their relationships to VBGF parameters, T and Lmax. Based on biological consideration and regressional definition, it was recommended to use following formulas for estimating of natural mortality rate of small pelagic fish such as anchovy. M = 0.3237 + 1.3174*(K) - 0.0036*(L∞) - 0.0117*(T); M = 0.2639 + 1.3676*(K) - 0.0003*(Lmax) - 0.0124*(T). Sabri Bilgin
2020-11-12T05:00:05Z 2020-11-12T05:06:25Z This item is in the repository with the URL:
2020-11-12T05:00:05Z Community structure and seasonal distribution of intertidal macrofauna from two rocky shores of Karachi coast Rocky shores are considered heterogeneous environments due to their composition and structure. Therefore, they support numerous habitats for flora and fauna. Organisms found on rocky shores are facing intense physicochemical conditions during tidal changes from upper to lower intertidal zones. Total (N=1888) specimens were collected on seasonal basis from intertidal zone during low tide from two rocky sites of Karachi coast, Buleji and Sunehri during January 2017 to December 2017. The highest number of individuals (N=1041), were recorded from Buleji than Sunehri (N= 847). The seasonal abundance in Mollusca were measured as (36.84%), (63.67%), (25.08) and (40.38%) from Buleji while from Sunehri (45.16 %), (46.01%), (48.65) and (42.79 %) during pre-monsoon, south-west monsoon, post monsoon and north-east monsoon season respectively. Group Arthropoda, Mollusca and Echinodermata were shows the highest abundance of the species at both sites as compare to other groups. The highest diversity index from Sunehri (H'=0.64) was measured in north-east monsoon season meanwhile, (H'=0.61) was measured in post monsoon season from Buleji coast. Evenness index (J'=0.25) in pre-monsoon season from Buleji and (J'=0.28) in south-west monsoon season from Sunehri coast. Season shows the great abundance of species as compare to other seasons. No significant correlation was observed in between seasons, water temperature and salinity with macrofauna groups at both sites. Qadeer Mohammad Ali Farhana S. Ghory Quratulan Ahmed Saima Siddique Shumaila Mubarak Sehrish Memon
2020-11-12T04:57:24Z 2020-11-12T05:15:49Z This item is in the repository with the URL:
2020-11-12T04:57:24Z Re-description of Lupocyclus philippinensis (Crustacea: Decapoda: Brachyura: Portunidae) Semper in Nauck, 1880 from the coastal waters of Karachi, Pakistan A specimen of the Lupocyclus philippinensis Semper in Nauck, 1880 commonly known as scissor swimming crab, was recently found in by catch of shrimp trawling and included as part of continuous taxonomic studies on crabs found in the coastal waters of Pakistan. The discovery is significant because it found after a long time. Redescription of L. philippinensis following the discovery of a female caught at Karachi fish harbor, Pakistan by Leene and Buitendijk (1952). Hamid Badar Osmani Farah Naz Noor Us Saher
2020-11-11T20:21:54Z 2020-11-11T20:21:54Z This item is in the repository with the URL:
2020-11-11T20:21:54Z The fishery of Lake Victoria, Uganda The only comprehensive assessment of fish stocks in Lake Victoria was undertaken during the period 1968/71 by the UNDP/FAO/EAFFRO. This work established for the first time an order of magnitude for the standing stocks of fish at 248,029 metric tons, in the Uganda portion of the lake, of which 205,592 tons (83%) comprised Haplochromis (NKEJJE). The other dominant species (in order of dominance) included the tilapiines (NGEGE), Baqrus docmac (SEMUTUNDU), Ciarias mossambicus (MUDFISH), Synodontis victoriae (NKOLONGO) and Protopterus aethiopicus (MAMBA), Lates niloticus (NILE PERCH) then comprised less than 0.1% of the standing stock (Kudhongania and Cordone, 1974). Rastrineobola argentea (MUKENE), a pelagic shoaling species, was also rare. About 80% of this standing stock was concentrated in shoreline waters of 0-49 metres deep, mostly within the artisanal fishery zone. The vast open and deeper waters had only about 20% of the standing stock. J.O. Okaronon A.W. Kudhongania
2020-11-11T20:14:59Z 2020-11-11T20:14:59Z This item is in the repository with the URL:
2020-11-11T20:14:59Z Workshop report on the fisheries research on Lake Nabisojjo: Luwero district The workshop began at 10:45 a.m. with introductory remarks made by the District Fisheries Officer, Luwero. He welcomed the participants and thanked them for sparing time to come and attend the workshop despite their busy schedules. He expressed concern that the district had lost revenue and supply of fish from Lake Kyoga after the formation of Nakasongola District and that as a result, the population in the district now, largely fed on fish frames from Kampala fish factories. The convenor of the workshop requested the Director of FIRRI to be the chairman for all the workshop sessions. R. Ogutu-Ohwayo O.K. Odongkara L.M. Ndawula J.R. Kamanyi M. Kyangwa G. Magezi F. Wabulya D. Ssekitoleko E. Ssebale R. Sekajja J. Naluwairo
2020-11-11T20:07:30Z 2020-11-11T20:07:30Z This item is in the repository with the URL:
2020-11-11T20:07:30Z Proceedings of the stake holders' workshop on Kisoro Minor Lakes held 28th April 2000 at Kisoro Council Hall in Kisoro District Physical -chemical, algal composition and primary production in the four Kisoro minor lakes. The paper looked at the importance of the water environment for fish production and the optimal physical chemical indices. The recommendations were discussed with respect to management of the water environment.Invertebrate communities of four Kisoro minor lakes and their role in fishery production. The paper outlined the different micro and macro invertebrates found in the different lakes and the role they play in the food chain. Recommendations were discussed on the importance of invertebrates in fish production and how those not utilised could be made use of. T. Twongo
2020-11-11T19:54:27Z 2020-11-11T19:54:27Z This item is in the repository with the URL:
2020-11-11T19:54:27Z The fisheries diversity of Lake Mburo with reference to Lake Kachera and some other Ankole minor lakes Lakes Mburo and Kachera are part of the complex system of lakes known as the the Koki lakes. These lakes form part of the Victoria satellite lakes. The Koki lakes are separated by extended swamps. The fisheries of these lakes are important as they contribute to government efforts of increasing food security, poverty reduction and conservation of natural resource base. These lakes are important biodiversity areas because some of these lakes have been found to contain the native tilapiine Oreochromis esculentus (Ngege), absent or threatened with extinction in the main lakes Victoria and Kyoga. It's also important to note that this species is only unique to the Victoria and Kyoga lake basins (Graham, 1929, Worthington, 1929). The values of some of these lake fisheries are however, threatened by human. activities such as over exploitation, introduction of exotics especially water hyacinth which is already present in River Ruizi, habitat degra-dation among others. J.R. Kamanyi D. Mbabazi
2020-11-11T19:40:55Z 2020-11-11T19:40:55Z This item is in the repository with the URL:
2020-11-11T19:40:55Z The effect of herbicides on phytoplankton in Wazimenya Bay. L. Victoria During the in-lake herbicide trials in Wazimenya Bay, Cyanobacteria dominated the phytoplankton, constituting more than 85%. The green algae and diatoms were always rare. There was a low species diversity. Algal cell counts were generally lower below the Hyacinth mat (5m inside) than at the edge (Om). There was no significant difference in the cell counts from the Rodeo and Weedar-64 sprayed stations nor between those from the Weedar-64 and control stations. However, there was a significant difference in the counts between Rodeo and control stations. But, the control counts were almost always lower than the Rodeo counts, an observation which could not easily be explained S.M. Byarujali
2020-11-11T19:37:11Z 2020-11-11T19:37:11Z This item is in the repository with the URL:
2020-11-11T19:37:11Z The distribution an abundance of fishes in lake Victoria Kenyan part Replicate trawling was done in each month at each of 15 locations in Lake Victoria (Kenyan Part) from October 1977 through December 1981. In 806 hauls, 392,361 fishes were caught, and 20 species (11 families) were identified from the collections, (Haplochromis spp. were treated as one group). E. Okemwa
2020-11-11T19:30:11Z 2020-11-11T19:30:12Z This item is in the repository with the URL:
2020-11-11T19:30:11Z The decline of the native fisheries of Lakes Kyoga and Victoria and the impact of Nile perch, Lates niloticus on these fisheries There has been a decline almost to the total disappearance and in some cases apparently the extinction of most of the native fish species of Lakes Victoria and Kyoga since the development of the fisheries of these lakes begun at the beginning of this century. The Nile perch, Lates niloticus, a large voracious predator which was introduced into these lakes about the middle of the century along with several tilapiine species is thought to have depleted stocks of other fish. But other factors, such as overfishing, changes in the habitat which can result in fish kills or affect breeding and recruitment, plus competition with other species, appear to have contributed to the diminution in the stocks of other fish. The available information indicates that by the time the Nile perch was established, the stocks of the native tilapiine species had been reduced by over fishing. The Labeo victorianus fishery had similarly been destroyed by intensive gill netting of gravid individuals on breeding migrations. L. niloticus is however, capable of depleting the stocks of species which have disappeared and could have consumed the remnants - thus preventing their recovery. It is also directly responsible for the decline in the populations of the haplochromine cichlids which were abundant over most of these lakes when it was established. The native tilapiine species were also affected by the introduced species which have similar ecological requirements. R. Ogutu-Ohwayo
2020-11-09T03:53:57Z 2020-11-09T03:53:57Z This item is in the repository with the URL:
2020-11-09T03:53:57Z The current state of the fisheries in the Northern portion of Lake Victoria (Uganda) A study of species catch composition average size and geographical distribution was carried out in Napoleon Gulf, Buvuma Channel and Lungira Bay in Lake Victoria from 1981 to 1983. J. Okaronon T. Acere-Olai D. Ocenodongo
2020-11-09T03:50:28Z 2020-11-09T03:50:28Z This item is in the repository with the URL:
2020-11-09T03:50:28Z A comparison of certain aspects of the biology of Lates niloticus (Linne) in some East African lakes Lates niloticus nile perch occurs naturally in only two East African lakes L. Albert and L. Rudolf but Foss Record indicate a wider East African distribution in the past fossils of the genus Lates are found in the Miocene beds of Lake Victoria basin. J.M. Gee
2020-11-09T03:46:57Z 2020-11-09T03:46:57Z This item is in the repository with the URL:
2020-11-09T03:46:57Z Water control and impoundments the aquatic side Man's impact in water control and impoundment is great and increasing rapidly in tropical countries. Though sometimes underground water is extensively pumped, I most water con1lrol schemes start with a barrier impounding flowing. water; tending towards an increase in area of standing water on the earth, usually richer in nutrients than the flowing water before impoundment. New waters are colonized, rapidly by aquatic organisms, plants forming a succession towards climax species. Explosive reproduction of organisms, including an exotic species in Kariba and discussed. Tropical fish usually prefer the new standing to old running water conditions, resulting in numerical increases though the composition P.B.N. Jackson
2020-11-09T03:37:58Z 2020-11-09T03:37:58Z This item is in the repository with the URL:
2020-11-09T03:37:58Z A collection of fishes from the Aswa river drainage system, Uganda The collection described below was made in April 1960 by the Uganda Game and Fisheries Department, and came from tributaries of the upper Aswa river about 20 miles north of Soroti. The Aswa rises on high ground in the western region of Karamoja and joins the Nile about 30 miles north of Nimule. For part of its course the river flows close to Lake Kyoga and some of its tributaries in this area arise near streams draining into Kyoga. Thus, it is an area of some zoogeographical interest since, like Lake Albert, it can be looked upon as an incursion of the Nile into a zone characterized by the large number of endemic or geographically restricted species occurring in bodies of water isolated both from one another and from the Nile. P.H. Greenwood
2020-11-09T03:34:58Z 2020-11-09T03:34:58Z This item is in the repository with the URL:
2020-11-09T03:34:58Z The collection and use of socio-economic data for the fisheries of Lake Victoria Socio-economics very broadly concerns the interaction between basic resource systems and the human communities which depend upon them for subsistence and commercial welfare. The term "interaction" is relevant because the very act of deriving benefits from these systems --i.e. of exploiting them, obviously affects their state --i.e. their potential for continued exploitation. Socio-economic investigations thus involve a considerable array of issues, ranging from the organisation and pursuit of productive efforts (tapping the resource) to the final distribution of benefits (using the resource. C.T. Mukasa P.N. Karuhanga
2020-11-09T03:28:32Z 2020-11-09T03:28:32Z This item is in the repository with the URL:
2020-11-09T03:28:32Z The biology of Nile perch: condition factor, growth, reproduction and food/feeding in Mwanza Gulf, Lake Victoria From Nov. 1986 to Dec. 1988, data on the biology of Nile perch were collected during the trawl surveys of R. V. Kiboko along Mwanza Gulf. With the abrupt increase of Nile perch catches in the fishery in 1984 the need to monitor the catches and study the biology of fish was inevitable. Nile perch (Lates niloticus) introduced in this lake in 1960's has been found to be very successful occupying almost all habitats and covering a wide water depth from 2-60 m deep. Its rapid growth rate, high fecundity and the voracious predation nature has favoured its success. O.C. Mkumbo W. Ligtvoet
2020-11-09T03:22:05Z 2020-11-09T03:22:05Z This item is in the repository with the URL:
2020-11-09T03:22:05Z The habitats and habitat preferences of the young of the Lake Victoria Tilapia (Pisces-Cichlidae) The habitats of the Lake Victoria Tilapia species have been, described by Lowe (1956) and FRYER (1961). Although most of their work was done on fish of adult size, both of these workers noted something of the distribution of the fry, attention in particular being paid to habitat preferences and possible competition between native and exotic species. Little is known however of the factors, both physical and ecological, at play on the beaches and other parts of the shallow lake littoral which are universally used as a habitat by the young of Tilapia species. Furthermore since the above work was carried out several features have changed in Lake Victoria. The first of these, the rise in lake level, has during 1963 and 1964, submerged or changed the nature off the lake shore, rendering the papyrus swamp channels mentioned by LOWE (1956) unsuitable as habitats for fry. R.L. Weilcomme
2020-11-09T03:16:07Z 2020-11-09T03:16:07Z This item is in the repository with the URL:
2020-11-09T03:16:07Z The biology and ecology of introduced tilapiines and what impacts they have on the fishery in the Victoria and Kyoga lake basins Since 1951, several specie's of fish have been introduced to Lake Victoria with a twin object of establishing stocks of commercially valuable species capable of exploiting an ecological niche which was under-utilized, and of yielding adults whose large size would encourage the reintroduction of 5 inch gill-nets. Data were collected from lakes Victoria, Mburo, Kachera, Wamala, Kayugi, Nabugabo in the Victoria lake basin, Kyoga, Nawampasa and Nakuwa in the Kyoga lake basin and rivers Nile and Sio. Some satellite lakes in the Victoria and Kyoga lake basins since 1997 to date on the distribution, population structure, Length! weight relationships, condition factor, food, sex ratios and size at first maturity of 0. niloticus, 0. leucostictus and T zillii. Most 0. niloticus were encountered in the middle waters (4.1 p.n) followed by offshore waters (3 p.n) and fewest in the inshore waters (2.5 p.n) while were mostly in offshore waters (3.3 p.n) followed by inshore waters (2.8 p.n) and lowest in middle waters (1.8 p.n). Most 0. niloticus and 0. leucostictus lay in the size class of 16.0-20.9 cm TL (26.2 % and 41.5 % respectively), while it was 11.0-15.9 cm TL (55 %) for T zillii. 0. niloticus from River Sio had a very high condition factor K of 6.17. For 0. leucostictus 2.08 was the highest from Lake Wamala and 2.52 for T zillii from Lake Kyoga. Overall, the Blue green algae were the most important food group of both 0. niloticus and 0. leucostictus (43 % and 41.6 % respectively) while it was Diatoms for T zillii (16.5 %). There were generally more males than females in all the species giving ratios of 1:0.97 in 0. niloticus, 1:0.82 in 0. leucostictus and 1:0.63 in T zillii. Results from this study show that there are. major differences in the abundance, population structure, condition factor, size at first maturity and food of 0. niloticus in the lakes examined. J. Nagayi