58 research outputs found
Coelichneumon (Coelichneumon) victorianus HEINRICH 1966
No full textCoelichneumon (Coelichneumon) victorianus HEINRICH, 1966 M a t e r i a l: Laos, Hua Phan Prov., Ban Saleui, Phon-Pan-Mt., 20°13´30´´N 103°59´26´´E, 1350- 1900 m, 1♀ 5.V.2011, 1♀ 27.V.2011, 1♀ 12.IV.2012, 13 18.IV.2012, 13 23.IV.2012, 13 6- 11.IV.2014, 1♀ 11-18.IV.2014, 1♀ 30.IV.2014, leg. C. Holzschuh & natives. D i s t r i b u t i o n: Known from Myanmar, new for Laos.Published as part of Riedel, Matthias, 2017, Contribution to the Ichneumoninae (Hymenoptera, Ichneumonidae) of Southeastern Asia: 3. Heresiarchini, pp. 895-917 in Linzer biologische Beiträge 49 (1) on page 908, DOI: 10.5281/zenodo.535694
Reproductive biology of ningu, Labeo victorianus (pisces: cyprinidae), in the kagera and Sio rivers, Uganda
No full textWe investigated aspects of the reproductive biology of the cyprinid fish, Labeo victorianus, locally known as ningu, in the Kagera and Sio Rivers, Uganda. These rivers represent the last remaining refuges for this species within Uganda. L. victorianus is a highly fecund, potamodrometic fish that migrates upstream to spawn. Spawning is generally synchronised with the bimodal water level maxima observed within the rivers. There were, however, some deviations from this pattern. We caught sexually mature fish throughout the year in the Sio River, and noticed that spawing started before the second rainfall peak. Fish from the Kagera matured at significantly larger sizes than fish from the Sio River. Male and female fish, from both rivers, fed intensively during the non-breeding months accumulating significant fat reserves; a probable energy storage mechanism prior to their spawning migrations. The differences between the populations is probably a phenotypic response to differing abiotic factors such as river size, flow velocity and food availability
Induced ovulation, spawning, egg incubation, and hatching of the cyprinid fish Labeo victorianus in captivity
No full textNingu Lubeo victorianus is the only labeine fish within Lake Victoria and its catchment (Greenwood 1966; Reid 1985). This species, once widely distributed in the Lake Victoria basin and supporting a commercial fishery until the late 195Os, has declined due to overfishing (Cadwalladr 1965; Ogutu-Ohwayo 1990; Seehausen 1996). The L. victorianus fishery has not only collapsed but the species has also disappeared from some of its former habitats. Recent surveys in Uganda have only found two distant populations-one in the Sio River on the Uganda-Kenya border (0” I3’53”N, 34”00’30’E), and the second in the Kagera River on the Uganda-Tanzania border (0°56’28.1”S, 3 1’46’ 18”E) (Rutaisire 2003) (Fig. 1). Currently, there is growing interest to breed the fish for wild stock enhancement and culture as a food fish
Rhynchaustrobates (Rhynchaustrobates) victorianus Smit, 2015, n. sp.
No full textRhynchaustrobates (Rhynchaustrobates) victorianus n. sp. (Figs 10 A–C) Type material. Holotype male, Scrubby Valley Creek at Flat Rock Crossing, Grampians NP, 37 º 0 9.680 S 142 º 26.680 E, alt. 304 m asl, 17 -iii- 2008 (NMV). Paratype male: one male, Wannon River at crossing with Serra Road, Grampians NP, Victoria, Australia, 37 º 20.918 S 142 º 30.386 E, alt. 331 m asl, 15 -iii- 2008 (RMNH). Diagnosis. P 3 with a short ventral projection. Description. Male. Idiosoma papillate, dorsally 365 (356) long and 300 (292) wide, ventrally 437 (421) long. Dorsum with relatively small glandularia platelets; postocularia on a small plate, 46 (48) long. First coxae fused, medial suture lines of coxae obliterated. Cxgl– 4 lying near middle of fourth coxae, Vgl– 2 somewhat close to posterior margin of fourth coxae. Genital field with three pairs of acetabula, gonopore 72 long. Length of P 1 –P 5: 20, 54, 38, 62, 32. Length of I-leg- 4–6: 108, 106, 90. Length of IV-leg- 4–6: 110, 100, 78. Legs without swimming setae. Female. Unknown. Etymology. Named after the state of Victoria. Remarks. The new species is most similar to R. tasmanicus Cook, 1986, which has a longer and more bowed projection of P 3.Published as part of Smit, Harry, 2015, The water mite family Hygrobatidae Koch in Australia. The genera Aspidiobatella Cook, Australorivacarus Viets, Gondwanabates Imamura and Rhynchaustrobates Cook (Acari: Hydrachnidia), pp. 567-583 in Zootaxa 4033 (4) on page 580, DOI: 10.11646/zootaxa.4033.4.7, http://zenodo.org/record/23208
The reproductive biology and artificial breeding of ningu Labeo victorianus (Pisces: Cyprinidae)
No full textLake Victoria, the largest tropical lake, has faced an unprecedented assault on its ecosystem through a variety of anthropomorphic causes that include the introduction of Nile perch Lates niloticus and over-fishing. As a result there have been species extinctions and declining fish population trends. This thesis explores options for reversing these declining population trends and the restoration of collapsed fisheries based on indigenous non-cichlid species. A candidate species was chosen - the cyprinid fish Labeo victorianus. This thesis studied various aspects of L. victorianus' reproductive biology in two geographically distant populations. These included general reproductive patterns in relation to proximate environmental conditions, gonadal development and recrudescence, sex development, characterisation of genetic and morphological diversity, and induced spawning. Fish from both populations were found to be potamodrometic, and highly fecund, iteroparous spawners. L. victorianus was also shown to be an undifferentiated gonochorist, where all individuals pass through an intersexual juvenile stage prior to differentiation, and maturation to either sex. Sexual maturity was attained at a significantly larger size within the Kagera River than that of Sio River fish – possibly as a response to genotypic and/or phenotypic differences. Spawning seemed to be synchronised with rainfall in Kagera River - a pattern that was not strictly adhered to with the Sio River. Thorough microscopic investigation of recrudescence patterns indicated there was uninterrupted spawning in fish from the Kagera River followed by Type I oocyte atresia. In contrast, there was a 90% spawning failure, as characterised by Type II oocyte atresia, within the Sio River population. Aspects of spermatogenesis and sperm ultrastructure using light- and ultramicrotomic methods are described. Although the populations had varying reproductive biology parameters and were morphologically distinct, they remained undifferentiated at the mitochondrial level. Both populations were characterised by low nucleotide diversity – a feature attributed to a bottleneck event. The option of captive breeding was explored by conducting induced spawning experiments. Success was only achieved with a decapeptide Gonadotropic Releasing Hormone ([D-Arg⁶, Pro⁹-NEt])-sGnRH) in combination with a water-soluble dopamine receptor antagonist metoclopramide. This thesis stresses the importance of a research-oriented approach in the conservation of Lake Victoria's indigenous fish resources. It was concluded that information needed for the development of management policies can be generated within a reasonably short time period, of approximately three years, with modest levels of funding support
Enhancing productivity of Labeo victorianus ponds using maize flour as a carbohydrate source
No full textThis study investigated the effects of manipulating carbon–nitrogen (C/N) ratio and fish stocking density on pond productivity: total heterotrophic bacteria counts, plankton biovolume and benthic macro-invertebrates. Labeo victorianus juveniles were reared for 72 days in 18 hapas suspended in six ponds measuring 150 m2 at densities of 10, 15 and 25 fish m-2. Fish in hapas received a locally formulated and prepared feed containing 295 g kg-1 crude protein, and ponds were treated with a C/N ratio of either 10 or 20. All treatments were carried out in triplicate. Increasing C/N ratio from 10 to 20 increased phytoplankton by 13% and zooplankton biovolume by 25% in the water column (P <0.001). Total benthic macro-invertebrates biovolumes were also 30% higher (P <0.05) with a C/N ratio of 20 compared to 10. Total heterotrophic bacteria counts increased both in water and sediment by 29% while net yield increased by 15% from 1534 (C/N 10) to 1821 (C/N 20) kg ha-1 72 day-1. C/N ratio of 20 and a stocking density of 25 fish m-2 led to the highest yield, survival, production and net benefits. It is suggested that polyculture may lead to better utilization of pond communities to further improve pond productivit
Effect of C/N ratio levels and stocking density of Labeo victorianus on pond environmental quality using maize flour as a carbon source
No full textThe main obstacle in developing intensive fish culture is waste management which is detrimental to the environment. To mitigate environmental impacts associated with effluent discharge, measures should be put in place to avoid deterioration of the pond environment. The addition of carbon materials into culture facilities while manipulating the levels of carbon and nitrogen ratios is one of the best strategies of controlling ammonia and nitrite in ponds. This study was carried out in 18 hapas suspended in six, 150 m2 earthen ponds to investigate the effects of C/N ratios (10 and 20) and stocking density (10, 15 and 25 fish m- 2) on water quality, sediment quality and growth of Labeo victorianus. All treatments were carried out in triplicate during a time period of 72 days. A locally formulated and prepared feed containing 30% crude protein with a C/N ratio of 10 was applied. Maize flour was used as the carbohydrate source for manipulating C/N ratio and applied to the water column separately from the feed. Increasing C/N ratio from 10 to 20 reduced (P <0.001) the total ammonia nitrogen (TAN), nitrite–nitrogen (NO2–N) and nitrate–nitrogen (NO3–N) in the water column and total nitrogen in the sediment (P <0.001). It also raised sediment pH, organic matter and total phosphorus (P <0.001). The lowest protein efficiency ratio (PER), specific growth rate (SGR) and the highest food conversion ratio for the feed were recorded with a C/N ratio of 10 (P <0.05). Based on highest growth, survival, production and net benefits, C/N ratio of 20 and a stocking density of 25 fish m- 2 are optimal. Therefore, carbohydrate addition in L. victorianus culture is a promising option for sustainable aquaculture
Procorticacarus victorianus K.O. Viets 1978
No full textProcorticacarus victorianus (K.O. Viets, 1978) Material examined. Tasmania. 3 /0/0, Unnamed creek crossing road to Kanunnan Bridge-Couta Rocks, 41 º 0 8.142 S 144 º 57.003 E, alt. 50 m a.s.l., 22 -iii- 2008; 1 /0/0, Blackwater Rivulet at crossing with road Kanunnan Bridge-Couta Rocks, 41 º 10.006 S 144 º 54.801 E, alt. 132 m a.s.l., 22 -iii- 2008; 1 /0/0, New ton Creek at crossing with road B28, 41º 54.520 S 145 º 34.199 E, alt. 493 m a.s.l., 24 -iii- 2008. Victoria. 3 /0/0, Eurobin Creek downstream of Mt Buffalo NP entrance, 36 º 41.745 S 146 º 51.453 E, alt. 293 m a.s.l., 10 -iii- 2008; 23 /0/0, Owens River East Branch, Harrietville, 36 º 53.563 S 147 º 0 3.965 E, alt. 516 m a.s.l., 10 -iii- 2008; 1 /0/0, Buckland River at Twelve Mile, 36 º 51.199 S 146 º 51.621 E, alt. 381 m a.s.l., 12 -iii- 2008; 4 / 1 /0, Jimmy Creek at campground, Grampians NP, 37 º 22.339 S 142 º 30.203 E, alt. 379 m a.s.l., 15 -iii- 2008; 1 /0/0, Scrubby Valley Creek, at Flat Rock Crossing, Grampians NP, 37 º 0 9.680 S 142 º 26.680 E, alt. 304 m a.s.l., 17 -iii- 2008; 2 / 1 /0, Erskine River downstream of falls, Great Otway Ranges NP, 38 º 30.426 S 143 º 54.823 E, 31 -iii- 2008; 2 / 1 /0, Aire River at crossing with Binns Road, Great Otway Ranges NP, 38 º 40.103 S 143 º 34.805 E, alt. 240 m a.s.l., 1 -iv- 2008. New South Wales. 0/ 1 /0, Snowy River, Mt Kosciuszko NP, 36 º 25.836 S 148 º 19.303 E, alt. 1736 m, a.s.l., 5 -xii- 2003; 0/ 1 /0, Sawpit Creek, at crossing with Kosciuszko Road, Mt Kosciuszko NP, 36 º 20.984 S 148 º 33.818 E, alt. 1240 m a.s.l., 6 -xii- 2003; 6 / 2 /0, Creek no. 1 at crossing with Alpine Way, Mt Kosciuszko NP, 36 º 27.758 S 148 º 22.926 E, alt. 1268 m a.s.l., 8 -xii- 2003; 7 / 3 /0, Thredbo River near Dead Horse Gap, Mt Kosciuszko NP, 36 º 31.354 S 148 º 15.825 E, alt. 1589 m a.s.l., 8 -xii- 2003; 6 / 9 /0, Leather Barrel Creek, Mt Kosciuszko NP, 36 º 31.559 S 148 º 11.611 E, alt. 999 m a.s.l., 8 -xii- 2003; 3 / 5 /0, Thredbo River at Thredbo Diggers Picnic Area, Mt Kosciuszko NP, 36 º 26.753 S 148 º 25.487 E, alt. 1136 m a.s.l., 8 -xii- 2003; 7 / 5 /0, Swampy Plains River at crossing with Alpine Way, Mt Kosciuszko NP, 36 º 23.121 S 148 º 10.837 E, alt. 425 m a.s.l., 9 -xii- 2003; 1 /0/0, 6-xi- 2005, Hortons Creek at crossing with road Grafton-Armidale, 30 º 0 0.006 S 152 º 40.952 E, 6 -xi- 2005. Remarks. Thus far known from Victoria and New South Wales, and here reported for the first time from Tasmania.Published as part of Smit, Harry, 2015, The water mite genus Procorticacarus K. O. Viets in Australasia (Acari: Hydrachnidia, Hygrobatidae) in Zootaxa 3956 (1), DOI: 10.11646/zootaxa.3956.1.3, http://zenodo.org/record/24131
A discussion of possible management methods to revive the Labeo victorianus fishery of Lake Victoria, with special reference to the Nzoia river, Kenya
No full textLabeo victorianus Boulenger, the "ningu", is commercially the most important migratory fish of Lake Victoria, as well as being one of the most abundant of all species landed. Annual catch records of the Fisheries Departments of Uganda, Kenya and Tanzania show that a high yielding seasonal, floating gill net fishery is based on the concentration of sexually mature fish at the river mouths at the time of migration during the bi-annual floods. Migrating fish used also to be caught in high numbers at "kek" barrier traps across the river, as at Hainga on the Nzoia river. Since the heavy exploitation at the river mouth which occurred with the introduction of nylon gill nets in 1956
A discussion of possible management methods to revive the Labeo victorianus fishery of Lake Victoria, with special reference to the Nzoia river, Kenya
No full textLabeo victorianus Boulenger, the "ningu", is commercially the most important migratory fish of Lake Victoria, as well as being one of the most abundant of all species landed. Annual catch records of the Fisheries Departments of Uganda, Kenya and Tanzania show that a high yielding seasonal, floating gill net fishery is based on the concentration of sexually mature fish at the river mouths at the time of migration during the bi-annual floods. Migrating fish used also to be caught in high numbers at "kek" barrier traps across the river, as at Hainga on the Nzoia river. Since the heavy exploitation at the river mouth which occurred with the introduction of nylon gill nets in 1956
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