Length-weight relationships of five species of the family Sparidae in the Gulf of Guinea

Length-weight relationships are presented by sex and by country for five species of the family Sparidae (Pugrus caeruleostictus, Pagellus bellottii, Dentex canariensis, Dentex congonensis, Dentex angolensis) sampled in April 1990 during the Guinea '90 trawling survey off Sierra Leone, Liberia, Cote d'Ivoire and Ghana.

Preliminary studies of the dual role of cotton-seed cake as fish feed and fish pond fertilizer in aquaculture

Many locally available fish feeds have been tried in fish culture. These include guinea corn, soya bean, groundnut cake and rice bran. Cotton seed cake has been successfully used as a fishpond organic fertilizer at Ado-Ekiti Government fish farm. Three fishponds stocked respectively with common carps, Heterotis, Tilapia spp., Clarias lazera and Heterobranchus were fed with cotton seed cake. Carps, Tilapia and Heterotis increased rapidly in weight and length while the catifishes did not grow

Investment prospects in marine capture fisheries

An examination is made of investment prospects in the Nigerian marine fisheries, considering the following sectors: inshore demersal fishery; inshore pelagic fishery; and the offshore pelagic fishery. The marine fisheries resources of countries with which Nigeria has bilateral fishing rights agreements are discussed, considering Equatorial Guinea, Guinea Conakry, Guinea Bissau, Senegal and Mauritania. Fishing gear and methods for the marine fishery sectors are outlined. Market potentials for fish products and profitability are also examined

Aquaculture Asia, Vol.14, No.3, pp.1-44, July-September 2009

Sustainable aquaculture Contrasting community management and revenue sharing practices of culture-based fisheries in Lao PDR Saphakdy, B., Phomsouvanh, A., Davy, B., Nguyen, T.T.T. and De Silva, S.S.; Floodplain aquaculture in Begumgonj: New horizon for rural livelihoods in Bangladesh Hossain, M. S.; Promoting small-scale inland aquaculture in Papua New Guinea Edwards, P.; Group approach to shrimp farming: The key to sustainability Kumaran, M.; Research and farming techniques Native catfish culture - a technology package for fish farmers Haniffa, M. A.; An assessment on the influence of salinity in the growth of black clam (Villorita cyprinoides) in cages in Cochin estuary with a special emphasis on the impact of Thennermukkom Salinity Barrier Arun, A. U.; Aquatic animal health EUS in Asia and Africa: Stimulus for regional initiatives!!! Mohan, C.V. Marine Finfish Aquaculture Network Offshore opportunities for artisanal aquaculture Stock, C.; Grouper aquaculture in Brazil Sanches, E.G. and Von Seckendorff, R.W. NACA Newsletter

A biologically active peptide in the skin of lampreys (Eudontomyzon danfordi vladykovi). [Translation from: Z.Naturforsch. (B), 26(10), 1021-1023, 1971. ]

In recent years interest in the production and description of kinin-type substances has been greatly intensified. So, for example, bradykinin, phyllokinin, physalaemin, ranatensin and caerulein could be extracted from the skin of amphibians as well as. eledoisin out of the salivary glands of Eledon moschata. An examination of lampreys seemed to us particularly profitable in the search for the incidence of further kinins. Ammocoetes of different sizes and also adults of both sexes of the species Eudontomyzon danfordi vladykovi were studied in this research. This species is found in many tributaries of the Danube. Skin extracts were tested on on isolated rat uterus, rat duodenum, guinea pig ileum and rabbit jejunum, further tests were done in order to determine a peptide character of the biologically active substance.

Étude quantitative de l'upwelling sur le plateau continental ivorien

A wind-driven upwelling occurs on the continental shelf of Ivory Coast during the northern summer months; by studying the average conditions in the wind field, it has been found that in steady state the vertical speed upwards does not exceed 70 cm per day. The vertical flow per km super(2) is estimated in 46 m super(3)/s for a channel 50 m depth and in 92m super(3)/s for a channel 300 m depth. This study does not include the inclination of isopycnes in geostrophic adjustment with the variations of the Guinea current.

Crustacés et Helminthes parasites de l'Albacore (Thunnus albacares) du Golfe de Guinée - note préliminaire

This note presents the results of a current study on the parasitism of the yellowfin Thunnus albacares in the Gulf of Guinea: a list of encountered crustaceans and helminths, remarks concerned with localisations, frequencies and intensities of the infestations is given. A hypothesis on the existence of three ecological stocks corresponding to three great fishing areas of the Gulf is suggested.

Évaluation de la production primaire et de la chlorophylle à partir des données hydrologiques. Application au Golfe de Guinée

Quantitative relationships between nitrate distribution, chlorophyll and primary integrated values have been used to evaluate the phytoplankton abundance in the Gulf of Guinea. Data of Guinee I cruise (May-July 1968) of the R.V. Jean Charcot have been used. They show a large oligotrophic convergence area (< 250 mg C/m2/J). A relationship previously found between the depth of the nitracline (first level where the nitrate appears) and the depth of the thermal maximum gradient is confirmed. From a practical point of view, this relationship is very useful since it allows, when the biological or chemical data are not available, a rough estimation of phytoplankton integrated biomass and production in the water column, from a temperature profile.

Peuplements zooplanctoniques dans les régions de remontées d'eau du littoral atlantique africain

The introduction is followed by a resume of the biogeographic factors and the principal work. The characteristics of zooplankton in different regions are presented based on regular research in Santa Helena Bay and Walvis Bay and the research carried out by William Scoresby. Certain factors of the digestive system of South African plankton are discussed. The next section concerns research in intertropical and equatorial regions in the Gulf of Guinea. It considers the littoral region of Angola, the Pointe Noire region and discusses the density and complexity of stocks. The last section concerns the zooplankton of Nigeria, Ghana and the Ivory Coast and discusses the grouping of species and compares the results.

Excrétion organique du phytoplancton et activité bacterienne hétérotrophe dans le Dôme de Guinée (Océan Atlantique Tropical Est)

Primary production rates in the Gulf the Guinea (east tropical Atlantic) were measured with in situ incubations. The extracellular organic carbon passed through 0.8 u pore size membrane filters averaged 29.5% of the carbon fixed by photosynthesis. These is a good linear correlation (r=0.86) between assimilation and organic excretion. The significance and limits of the method for the measurements of low rates of photosynthesis is discussed. The influence of ecological factors (nutrients, light and stability) cannot be demonstrated. The importance of bacterial regeneration processes by reutilization of algal extracellular products is assessed.

La circulation superficielle dans la partie occidentale du Golfe de Guinée

Direct current measurements carried out for 10 years in the Gulf of Guinea clearly show the importance of transverse circulation. The general pattern of currents is characterized by an anticyclonic gyre. The seasonal variations of this circulation are calculated through the study of the 3-monthly averaged geostrophic currents. The biological consequences of such a circulation are outlined.

Caractérisation des situations hydro-biologiques et potentialités de pêche thonière au Cap Lopez en Juin et Juillet 1972 et 1974

Surface temperature was measured by remote sensing through Cape Lopez (Gulf of Guinea) frontal region during the fishing season in June and July 1972 and 1974. Twelve typical situations are analysed through four main directions: surface situation, tendency, hydrobiological structure and availability to fisheries. The tuna behavior is analysed in relation with the frontal zone movements and a mechanism which tends to aggregate important shoals of tunas is presented.

Rélations hydrométéorologiques sur les côtes du Golfe de Guinée: influence de l'orientation de la côte

The Gulf of Guinea is remarkable for its abundant precipitations and negative anomalies of the surface water temperature. This originality comes from the southern monsoon which transfers the cold season to the middle of northern summer up to latitude 10 degrees North. Yearly precipitations, which can vary along the coast, are well in correlation with coast crossing air flow (r=0.71) and with the sea-air temperature difference (r=0.72). Precipitations provide a better correlation with surface temperatures (0.72) than with salinities (-0.63). The wind influence upon negative anomaly of the surface temperature is more clear on N-S coast (r=0.98) than on W-E coast (r=0.73) of the Gulf. Temporal correlations calculated on 16 years of observations in Pointe-Noire are in connection with previous spatial correlations. Coastal hydroclimates are thus likely to be deduced from meteorology.

Biologie de Penaeus duorarum en Côte d'Ivoire. 3. Étude des variations quotidiennes des rendements et leur relations avec l'hydroclimat. Essai de généralisation au Golfe de Guinée

Hydroclimatic conditions in the Gulf of Guinea between Senegal and Nigeria are briefly described emphasizing the seasonal variations of transparency. Analysis of the Abidjan based shrimp fleet allowed to the description of the seasonal variations of activity rhythms for Côte d'Ivoire, Ghana, and Nigeria. These rhythms are different between seasons, between fishing grounds, and sometimes even between depths on a given ground. These variations follow the turbidity ones. Diurnal activity is observed in very turbid waters, nocturnal and transition activity in clearer ones. The authors assume that the basic behaviour is a nocturnal one, but that the shrimp-trawlers catches reflect some apparently different ones resulting from diel variations in the stock availability. To explain the apparently diurnal behaviour observed most of the year over the whole Gulf of Guinea it is suggested that these generally benthic shrimps become nectonic at night when turbidity is very high. The results obtained in Ivory Coast, Ghana and Nigeria are compared to those from Senegal where hydroclimatic conditions are different. The similarities are emphasized. The differences in observed behaviour are supposedly caused by the cold season water temps which are sufficiently low to disturb the nor mal activity rhythm.

Le courant de Lomonosov dans le fond du Golfe de Guinée en mai 1973

A cruise of the R. V. Capricorne in May 1973, in inner part of the gulf of Guinea, allowed the authors to identify the main part of the Atlantic circulation at the longitude of 5 degrees E, between 4 degrees N and 4 degrees S. It gave new data on the termination of the equatorial undercurrent. At the equator, under the westward south equatorial current flows the Atlantic equatorial undercurrent with a maximum eastward velocity of 90 cm/sec at 30 m depth linked to a salinity maximum higher than 36.20 ppt. Below the equatorial undercurrent, about 80-100 m depth, flows a westward current with a velocity as high as 30 cm/sec. At 4 degrees S, the south equatorial countercurrent is well delineated by a high salinity core (more than 36.10 ppt) at 30 m depth with an eastward velocity core of 40 cm/sec. On the contrary, near 3 degrees 30N, a high salinity core (36.10 ppt) flows westwards with a speed of 40 cm/sec at 40 m depth: it is the "return flow" of the undercurrent (Hisard and Moliere 1974). At 4 degrees N the Guinea current carries eastwards surface salinities of 34.50 ppt at 40 cm/sec. Off Cape Lopez (0 degrees 35'S-8 degrees 42'E) the high salinity core of the undercurrent becomes wider near the shore. It is 25m wide offshore, and 70 m wide near the cape. A part of undercurrent water extends northwards, then flows westwards with the subsurface westward circulation in the inner part of the Gulf of Guinea. Another part flows south-southwestwards in a high salinity tongue along the African coast to 4 degrees S. South-west of Cape Lopez, the trades divergence contributes to an upwelling of cold and high salinity water; this water increases at the Cape Lopez front.