Herbicidan control of water hyacinth at Ere, Ogun State: implications for fish production

A brief account is given of a pilot demonstration of the chemical control of water hyacinth (Eichhornia crassipes) at Ere (a channel) in Nigeria using the herbicide glyphosphate. Results suggest that there was an increase in the nutrient content of the channel after herbicide application. This implied an upsurge of available food for fish and other aquatic organisms within the channel after the herbicide application. The decaying water hyacinth mass which sinks into the medium is likely to boost nutrient content, promoting the growth of fish and other aquatic animals. It is concluded that herbicidal control of water hyacinth is possible, especially under specialists' management with the conservation of fish and other non-target aquatic organisms alongside improved fish production

Copépodos calanoideos marinos del área de Mar del Plata con la descripción de Pontella marplatensis n.sp

This paper deals with the Calanoidean Copepod of the Mar del Plata area (Province of Buenos Aires, Argentina) which were obtained in 71 starions during 5 oceanographic cruises performed on April, August-September and December, 1963 and on March and May, 1964. The area under study ranges from 37°20' to 38°45' L.S. and from 56°30' to 58°10' L.W. The samples were gathered from coastal, surface waters. Quantitative data could not be obtaine, except for and estimation of the time of flow through the plakton net. A total of 13 species of Calanoid Copepods were found. The species found were described, and drawings were made of those structures wich ere considered of taxonomic value. Data were included on the geographic distribution, with emphasis on South Atlantic and areas Antarctic.

Effect of dietary inulin as prebiotic on growth, survival and intestinal bacterial density of juvenile great sturgeon (Huso huso)

Use of prebiotics, nondigestible dietary ingredients that beneficially affect the host by selectively stimulating the growth of and/or activating the metabolism of healthpromoting bacteria in the intestinal tract, is a novel concept in aquaculture. An 8-week feeding experiment was conducted to investigate the effects of dietary prebiotic inulin on the growth performance, intestinal bacterial density, body composition and values of blood serum enzymes in the juvenile great sturgeon (Huso huso). Three replicate groups of fish (initially averaging weight 16.14±0.38g) were fed diets containing prebiotic inulin at levels ranging from 1% to 3%. The basal diet was contained 3% cellulose. The results of linear regression showed there was a negative relationship between some performance indices including weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), net protein utilization (NPU), energy retention (ERE), feed efficincy (FE), protein retention (PR) and supplementation level of inulin. At the end of trial, the 1% inulin treatment insignificantly showed an enhaced survival between the treatment groups. Intestinal lactic acid bacteria (LAB) increased in group treated with 1% inulin compare to other groups. No significant difference were observed in body composition and level of serum enzymes (P>0.05). Moreover there was significant correlation between ALT and LDH values (P<0.01). Result obtained in this study shows that the prebiotic inulin didn’t influence the increase of the growth performance of juvenile great sturgeon and it is not appropriate for supplementation in the diet of beluga.