A database for the industrial trawl fishery of Cote d'Ivoire

Fishery statistics for the industrial trawl fishery of Cote d'Ivoire have been well documented since 1968. However, data processing has changed significantly with time and some of the data files have been lost. In 1997, the Centre de Recherches Oceanologiques d'Abidjan decided to retrieve and process all trawl data available from different sources. This paper gives an overview of the database covering the period 1968 to 1997 and describes its coverage, format, structure and use. The database was developed using MS ACCESS and is a powerful tool for storing information about this fishery, and for analysis of its dynamics over a period of 30 years.

Swimming crab Callinectes amnicola (Decapoda-Portunidae) capture analysis of a lagoon with high continental influence (Aby Lagoon, Cote d'Ivoire, West Africa)

The study describes the main causes of captures and productions decreasing of swimming crab Callinectes amnicola (Decapoda Portunidae) in Aby lagoon complex. For that, docks of two Sub Prefectures of Adiaké and Assini-Mafia respectively including the villages of Adiaké, Anga, Assomlan, Epleman, Aby and Man-Man, M'Bratty, Assini-Ngouankro and Assini-Mafia were studied from 2006 to 2009 and completed with previous results obtained from 1988 to 2005. Field investigators were identified by site/village and they recorded daily activities of fishermen (number of effective fishermen, number of gears and area of fishing, duration of fishing, types and quantity of bait) and landing of swimming crabs. During recent period of the study, total production decreased from 3742 tons in 2006 to 1500 tons in 2009. Matrix correlations and correlation analysis indicated that this downward trend was due to the increase of the number of fishermen, number of fishing gear, the decrease in female crabs capture and degradation of the environment related to gradual closure of the Assini-Mafia channel. Despite this decline, total production in Aby lagoon remained high compared to the productions of some lagoons of the country and the region. Given the importance of fishing swimming crabs in Aby lagoon, since it concerns many young people and it is a source of income, stringent measures for sustainable and responsible management must be taken and implemented as part of a co-management plan involving all stakeholders to sustainably manage the resource

A comparative study on the hatching of common carp eggs in hapa and hatchery (model CIFE D-80)

Common carp (Cyprinus carpio) eggs were incubated to study the efficiency of hatching in hapa and hatchery. During incubation the recorded temperature was 21-28 degree C and 20-31 degree C, dissolved oxygen 6-9 ppm. and 3-5 ppm., total alkalinity 180-250 ppm. and 28-62 ppm. respectively in the hatchery (model C.I.F.E. D-80) and hapa. CO sub(2) was totally absent in the hatchery, but recorded 3-10 ppm. in the hapa. The flow of water was maintained at 1.25 l/minute/jar in the hatchery. Under the above environmental conditions the eggs hatched in 42-51 hrs. in the hatchery and 61-81 hrs. in the hapa from egg to spawn thereby establishing the hatchery to be a better hatching system for carp eggs.

Antibacterial effect of the Indian squid, Loligo duvauceli (d'Orbigny), ink

The ink of the Indian squid Loligo duvauceli (d'Orbigny) was tested for antibacterial activity. The antibacterial effect of bacteria present in the ink gland was also tested. Only one type of bacteria was found to be present in the ink gland of squid and was identified as Photobacterium leiognathi. Among the various forms of ink extracts, the precipitated and freeze-dried ink showed more pronounced antibacterial effect against Gram-negative bacteria, Salmonella, spp. Escherichia coli, Vibrio cholerae, V. parahaemolyticus and Pseudoinonas spp., and a less pronounced effect against Gram-positive bacteria, Staphylococcus spp. and Micrococcus spp., P. leiognathi did not inhibit any of the above bacteria. The antibacterial activity was associated with the compounds of the ink.

Effects of physiological doses of vitamin D sub(3) (Cholecalciferol) on induced molting and growth in giant freshwater prawn, Macrobrachium rosenbergii (de Man)

Effects of three different doses of vitamin D sub(3) on molting, growth, and calcium and phosphate composition of tissue and molt during the grow-out of the giant freshwater prawn Macrobrachium rosenbergii (average weight 10.56 ± 0.20 g), obtained from a grow-out pond, were studied. Intramuscular doses of vitamin D sub(3) (100, 500 and 2000 IU/kg body weight) were given on the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, 15th, 20th, 25th and 30th days. All the experimental animals were fed with a basal diet containing fish meal, shrimp meal, wheat flour, groundnut de-oiled cake, soybean meal and wheat bran at 3% of the body weight. The numbers of molts were recorded as 20±0.50, 29±1.16, 51±1.87, and 30±1.60 in control, 100, 500 and 2000 IU/kg body weight physiological doses, respectively. Maximum growth was recorded in prawns given 500 IU/ kg dose. Survival was between 58.33 ± 9.13 and 77.77 ± 8.61%. The ash content and calcium level increased significantly (p<0.05) and recorded the highest values in 500 IU/kg physiological dose. However, the inorganic phosphate (P sub(i)) content recorded the highest values in tissue in 2000 IU/kg dose (p<0.05, F = 50.60613). There is no significant difference in calcium contents (p>0.05) in both tissue and molt at 500 and 2000 IU/kg doses. It was found that a higher physiological dose (2000 IU/kg) of vitamin D sub(3) increased the rate of mortality. Results have shown that vitamin D sub(3) has a positive impact on the growth and survival of M. rosenbergii and it interferes with the metabolism of Ca and P sub(i), in tissue, and alters molting frequency. Results on physiological dose suggest an alternative and effective dietary supplementation method of vitamin D sub(3) in the grow-out phase of M. rosenbergii.