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  • 1
    Electronic Resource
    Electronic Resource
    Salinity influence on the early stages of the African catfish (1998)
    Springer
    Aquaculture international 6 (1998), S. 369-379 
    Details
    ISSN: 1573-143X
    Keywords: African catfish (Clarias gariepinus) ; Hatchability ; Salinity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Experiments were conducted to determine the effect of various incubation salinities on the hatching and survival of eggs and hatched fry respectively of the African catfish (Clarias gariepinus). The optimal salinity for the hatching of the eggs ranged from 0–5‰. Above 5‰, hatching was significantly low and no hatching occurred at 8‰ incubation salinity. Median lethal times (LT50) for fry hatched in 0, 2 and 4‰ incubation salinities, when abruptly transferred to 10‰ were 59, 49.5 and 50 h respectively. Similarly, LT50 for fry hatched in 0, 2 and 4‰ incubation salinities, and abruptly transferred to 12‰ salinity were 17, 22 and 12.50 h respectively. Increase in incubation salinity of the eggs did not seem to enhance the salinity tolerance of the hatched fry. The gradual (stepwise) increase in salinity of 1‰ per day of the catfish fry hatched in various incubation salinities (0, 1, 2, 3, 4, 5 and 6‰) had median lethal salinity values of 8, 8, 8, 10, 10, 11 and 11‰ respectively. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009228820875
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Variation in the physico-chemical features and phytoplankton of new Calabar river at Aluu, Rivers State, Nigeria. (2008)
    Details
    Publication Date: 2021-05-19
    Description: The physico-chemical features and phytoplankton community of the upper reaches of the New Calabar river at Aluu were studied at high and low water slacks for a period of 12 months. The water was acidic (pH 5.5 – 6.5) with low alkalinity (10 – 20mg CaCO3 L-1 and characteristically soft (total hardness ranging from 10 to 60mg CaCO3L-1). There was obvious seasonal flux in the silica level, with dry season having higher values than wet season. The phytoplankton was predominated by the diatoms, which constituted more than 85% of the total phytoplankton population. The predominant taxa were Melosira sp. Tabellaria spp. Surirella spp. and Navicula spp. The phytoplankton density was significantly higher during the dry season than rainy season (Czekanowski’s Coefficient.Cz = 0.332) but there was no significant difference between the high and low tide values (Cz = 0.66).
    Description: NIOMR
    Description: Published
    Keywords: Phytoplankton ; Physicochemical properties ; Physicochemical properties ; Phytoplankton
    Repository Name: AquaDocs
    Type: Report
    Format: 18
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  • 3
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    Functional roles of mangroves of the Niger Delta to the coastal communities and national economy (2021)
    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23434 | 19325 | 2018-05-02 08:11:31 | 23434 | Fisheries Society of Nigeria
    Details
    Publication Date: 2021-07-14
    Description: Mangrove swamps supply various goods and provide invaluable ecological services, especially as critical habitats for fish breeding. These functions are discussed in the context of rural livelihoods of coastal dwellers in the Niger Delta in particular, and the contribution to national economies in general. The decline in capture fisheries production in Nigeria is partly linked to massive mangrove loss in the Niger Delta. This provides basis for urgent evolution of effective mangrove conservation schemes in the Niger Delta and for focused research on the interaction between the delta mangroves and inland/coastal fish recruitment and production dynamics.
    Description: Includes:- 23 refs.
    Keywords: Ecology ; Fisheries ; Nigeria ; Mangroves ; brackishwater environment ; Mangroves ; Fishery economics
    Repository Name: AquaDocs
    Type: conference_item , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 119-123
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  • 4
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    Water quality of Bodo Creek in the lower Niger Delta basin (2021)
    In:  http://aquaticcommons.org/id/eprint/22475 | 19325 | 2018-02-22 14:59:59 | 22475 | Fisheries Society of Nigeria
    Details
    Publication Date: 2021-07-06
    Description: The dynamics of some physicochemical parameters of Bodo Creek on the upper reaches oftheAndoni-Bonny river system were studied between December 2005 and July 2006. There weresignificant differences (P〈0.05) in Secchi Disc Transparency and salinity, while temperature,Dissolved Oxygen (DO), Biological Oxygen Demand(BOD), phosphate and nitrate concentrationswere similar (P〉0.05) between the spatial grids. The values recorded ranged from 26.7 to 30.1°C(Temperature);73-157 cm (Secchi Disc Transperancy); 6.2-22.7%0 (Salinity); 4.6-11.8 mgtl (DO);0.7-8.2 mgtl (BOD); 0.047-2.300 mgtl (Phosphate) and 0.013 to 0.873 mgtl (nitrate). There wereobvious seasonal flux in the ecological variables (P〈0.05), except nitrate concentrations that werenot statistically significant (P〉0.05). The usefulnessof the results infuture monitoring and possiblereasons for the observed environmental gradients are discussed.
    Keywords: Aquaculture ; Environment ; Fisheries
    Repository Name: AquaDocs
    Type: conference_item , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 28-33
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  • 5
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    Mortality rates of fish species within the Andoni River, Niger Delta, Nigeria and management measures (2021)
    In:  http://aquaticcommons.org/id/eprint/22984 | 19325 | 2018-03-03 07:19:23 | 22984 | Fisheries Society of Nigeria
    Details
    Publication Date: 2021-07-12
    Description: Pooled one-year (January to December, 1999) length-frequency data of fish speciessampled from catches of five randomly selected artisanal fishers, using unmotorized dug-out canoe were fed into FISAT (FAO-ICLARM Stock Assessment Tool) to evaluate mortality coefficients. The resultant natural mortality coefficients of the11 commercially important fish species showed that Sarotherodon melanotheron (2.24y ('), Galeoides decadactylus (1.96y(1), Eucinostomus melanopterus (1.58 y(,), Tilapia guineensis (1.44 y('), Pseudotolithus elongatus (1.22 y(,) and Ilisha africana (1.08 y(1) had the highest natural mortality rates and indicative of fast growth (i.e. rapidly approaching asymptotic length (Loo); the reverse being true for Chrysichthys nigrodigitatus (0.66 y(1); Pomadasys jubelini (0.74 y('); Ethmalosa fimbriata (0.78 vr'). Lutjanus goreensis and Uzagrandisquamis (0.87 yr'). The generally high total mortality values of 0.88 y(1 for C. nigrodigitatusto3.83 y(' (P. elongatus) points to death due not only to legal fishing activities but also great impacts from illegal and obnoxious fishing practices, pollution, environmental degradation, and the consequent need for management of the fishery resource within the Niger Delta of Nigeria. Management measures such as enforced licensing and registration of fishers and fishing craft, establishment of marine reserve areas and fishing registration centers would enhance sustainable use of the economically viable fishery resources within the coastal states of Nigeria and West Africa at large. Pooled one-year (January to December, 1999) length-frequency data of fish speciessampled from catches of five randomly selected artisanal fishers, using unmotorized dug-out canoe were fed into FISAT (FAO-ICLARM Stock Assessment Tool) to evaluate mortality coefficients. The resultant natural mortality coefficients of the11 commercially important fish species showed that Sarotherodon melanotheron (2.24y ('), Galeoides decadactylus (1.96y(1), Eucinostomus melanopterus (1.58 y(,), Tilapia guineensis (1.44 y('), Pseudotolithus elongatus (1.22 y(,) and Ilisha africana (1.08 y(1) had the highest natural mortality rates and indicative of fast growth (i.e. rapidly approaching asymptotic length (Loo); the reverse being true for Chrysichthys nigrodigitatus (0.66 y(1); Pomadasys jubelini (0.74 y('); Ethmalosa fimbriata (0.78 vr'). Lutjanus goreensis and Uzagrandisquamis (0.87 yr'). The generally high total mortality values of 0.88 y(1 for C. nigrodigitatusto3.83 y(' (P. elongatus) points to death due not only to legal fishing activities but also great impacts from illegal and obnoxious fishing practices, pollution, environmental degradation, and the consequent need for management of the fishery resource within the Niger Delta of Nigeria. Management measures such as enforced licensing and registration of fishers and fishing craft, establishment of marine reserve areas and fishing registration centers would enhance sustainable use of the economically viable fishery resources within the coastal states of Nigeria and West Africa at large.
    Keywords: Fisheries ; Management
    Repository Name: AquaDocs
    Type: conference_item , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 95-99
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