Length-weight relationship and organ indices of pond raised and wild population of C. gariepinus (Burchell 1822) pisces-Claridae

Samples of C. gariepinus collected from the wild and cultured populations in Plateau and Niger States of Nigeria were analyzed for length-weight relationship and organ indices (Gonadosomatic index (GSI), hepatosomatic index (HSI), renalsomatic index (RSI) and somatic fat deposit index (PDI). High correlation and linear relationship between body length and body weight was observed in all sample population (P<0.05). A significant difference was observed between the GSI of males and females of both wild and cultured population and also between females of the wild and cultured population,(P < 0.05).There was no significant difference in HSI, CSI RSI and PDI of all the sample populations (P < 0.05).The importance of length-weight relationship and organ indices in fish production are discussed

Investigation of nematode Eustrongylides larvae infections in mudfish Clarias gariepinus and C. anguillaris from Bida floodplain of Nigeria

This is the first report and record of the determination whether mudfish Clarias were infected with the larvae of the nematode Eustrongylides. Also, documented the assessment of the socio-economic perceptions of three groups of fisher folks on the economy of infected mudfish Clarias fishing activities. Fifty-six (67.5%) of 83 mudfish Clarias caught by artisanal fisher folks were examined for the presence of the larvae of the nematode Eustrongylides. All the 8 sampled fishing localities in Bida floodplain of Nigeria had a mean intensity and abundance of at least 3 and 1 worm per fish per site, respectively. Two hundred and one (96.2%) of 209 worms recovered were from the musculatures at different depths resulting in undulations on the skin surfaces as grub-like presentations. The three groups of fisher folks assessed encountered economic losses from nematode infected mudfish Clarias which attract much debates or rejections during marketing due to its aesthetically displeasing appearance, faster deterioration, higher fragility in smoked form coupled with poorer taste compared to the wholesome ones. Infected female mudfish Clarias had higher worm burden than the males, for each fishing locality

Fish species identification in Canned Tuna by DNA Analysis (PCR-SSCP)

DNA in canned tuna is degraded into short fragments of a rew hundred base pairs. The polymerase chain reaction (PCR) was used to amplify short sequences of mitochondrial DNA, which were denatured and analysed by polyacrylamide gel electrophoresis (native PAGE) for detection of single strand conformation polymorphisms. Species specific patterns of DNA bands were obtained for a number of tuna and bonito species. DE: In Thunfischkonserven liegt die DNA in Form kurzkettiger Fragmente von wenigen Hundert Basenpaaren Länge vor. Mit Hilfe der Polymerase-Kettenreaktion (PCR) wurden kurze Sequenzen der mitochondrialen DNA vervielfältigt. Anschließend wurde die gebildete DNA in Einzelsträngen überführt, die durch eine native Polyacrylamidgel-Elektrophorese (PAGE) aufgetrennt wurde. Für eine Reihe von Thunfischen und Boniten ergaben die Einzelstränge artspezifische Bandenmuster, die auf unterschiedliche Konformationen der DNA-Stränge der einzelnen Fischarten zurückzuführen sind.

On methods of evaluation of bacterial production. [Translation from: Lietuvas TSR Mokslu Akademijos Darbai, C Serija 2(55) 3-9, 1971.]

By now a great deal of work is known concerning the methods of determining the production of bacteria or similar questions; among these the problems of a common terminology is discussed. The article discusses formulae of production of bacterial populations over time.

Investigations of certain eco-physiological characteristics of the broad and long-pincered crayfish in connection with their interspecific relationships. [Translation from: Lietuvas TSR Mokslu Akademijos Darbai, C Serija 2(40), 279-286, 1966.]

The results are described of eco-physiological investigations of the broad-pincered (Astacus astacus L.J.) crayfish and the long-pincered (Astacus astacus Esch.) crayfish, conducted in 1963—64 in the Institute of Zoology and Parasitology of the Academy of Science of the Lithuanian SSR, for the purpose of studying the interspecific relationship of these two species. In the course of the investigation were determined: the influence of the temperature of the environment on the consumption of oxygen by full grown individuals of both species and on the respiratory movements of the scaphognathites, the threshold temperatures and the saturation of the water by oxygen, the diel activity in the winter period.

Some data on the predacious behaviour of tendipidae larvae [Translation from: C. R. Acad. Sci. U.R.S.S. 111, 466-4, 1956]

A study has been made primarily of the food of the chironomid Procladius nigriventris: this includes Alona affinis, Bosmina coregoni, Camptocercus, Eucyclops serrulatus, Paracyclops fimbriatus, Acanthocyclops viridis, Harpacticoida, Diaptomus graciloides, Ostracods, Chironomus sp, Polypedilum sp and Tanytarsus sp. Chironomus larvae usually found in the gut are in their 1st or 2nd instars , though occasional 3rd instars are present. The study summarises other findings on the feeding behaviour of Procladius nigriventris.

On the number of generations of tendipes in collective ponds in Kuibyshchevskoi district [Translation from: C.R. Acad.Sci. U.R.S.S. 95, 1113-1115, 1954]

Three ponds were chosen for this study. The two lower ones were of 2 - 4 hectares in area, the depth of the littoral zone was 2.5 - 3 metres at the time of maximum flooding and the mud which covered the floor of the ponds was homogeneous and autochthonous in nature with very few vegetable remnants. The ponds which were originally set up in 1950. were intended for water supply and populated with Crucian Carp (for human consumption). A survey was done in the ponds in order to establish number and biomass of Tendipes semireductus. The author concludes that in these ponds T.semireductus has 2-3 generations per year.

Feeding of larval Cricotopus silvestris F. in relation to characters of structure of oral apparatus [Translation from: C.R.Acad.Sci.USSR.100, 1191-1193, 1955]

Laboratory research was done in order to study the feeding of larval Cricotopus silvestris F. in relation to characters of structure of oral apparatus. Results of the experiments are summarised and the oral apparatus morhologically described.

The content of organic matter in some waters in the Moscow region [Translation from: C.R. Acad. Soc. URSS, 61, 293-296, 1948]

There is at the moment no direct method of determining the organic matter content of natural waters. In 1940/41 8 different water bodies in central Russia were studied and their organic matter identified. The author concludes that there is currently no easy method to determine organic matter in water. A number methods need to be applied.

Pour les vingt ans du C.R.O.

Founded in 1959, the Centre de Recherches Océanographiques is now twenty years old. During its existence, its administrative structure and its internal organization have considerably changed. It is now a research center placed under the supervision of the State Secretary for Scientific Research but, for management, it has been committed to the care of Orstom, a French organization specialized into scientific and technological research in the developing countries. Orstom also partially finances the research work, whose aims are decided by special commissions, which in their choices take into account the fundamental options of the plans of development of the government of Côte d'Ivoire.