Optimization of fishing for stock enhancement of Rutilis rutilus and Scardinius erythropththalmus in forage fish-deficient Tunisian reservoirs.

Twenty specially designed fishing nets were used to catch broodstock of the forage fish roach and rudd (Rutilus rutilus and Scardinius erythrophthalmus). The monofilament gill nets were of different mesh sizes (18, 22, 24, and 26 mm) but of identical dimensions (4 × 50 m). The fish, caught in Sidi Salem reservoir in 2014, amounted to a total of 8901 roach and rudd caught at 41 different times; 3335 broodstock forage fish were transferred to 11 forage fish-deficient Tunisian reservoirs. The best yields (0.464 fish/m2) were obtained with fishing gear fitted with 18-mm mesh size; however, fish mortality with this net was very high, exceeding 83.36%. The greatest efficiency was obtained using nets of 22- and 24-mm mesh with a number of fish per unit effort (NPUE) of 0.181 and 0.173 fish/m2, and a mortality of 54.34 and 53.85%, respectively. Gill nets of 26-mm mesh size were inappropriate (lowest yield 0.129 fish/m2). Length of rudd and roach at first maturity and Gonadosomatic index (GSI) were measured, indicating that all transferred fish were mature. Transfer techniques were improved by holding the captured fish for 5 days before release into the host reservoir.

Characterization of fish assemblages and population structure of freshwater fish in two Tunisian reservoirs: implications for fishery management.

To monitor and assess the state of Tunisian freshwater fisheries, two surveys were undertaken at Ghezala and Lahjar reservoirs. Samples were taken in April and May 2013, a period when the fish catchability is high. The selected reservoirs have different surface areas and bathymetries. Using multi-mesh gill nets (EN 14575 amended) designed for sampling fish in lakes, standard fishing methods were applied to estimate species composition, abundance, biomass, and size distribution. Four species were caught in the two reservoirs: barbel, mullet, pike-perch, and roach. Fish abundance showed significant change according to sampling sites, depth strata, and the different mesh sizes used. From the reservoir to the tributary, it was concluded that fish biomass distribution was governed by depth and was most abundant in the upper water layers. Species size distribution differed significantly between the two reservoirs, exceeding the length at first maturity. Species composition and abundance were greater in Lahjar reservoir than in Ghezala. Both reservoirs require support actions to improve fish productivity.

Vancomycin-resistant Enterococcus faecium in Algeria: phenotypic and genotypic characterization of clinical isolates.

INTRODUCTION: vancomycin-resistant Enterococcus faecium (VREfm) is a major public health problem worldwide. The aim of our study was to determine the microbiological, epidemiological and molecular characteristics of VREfm isolated in north-central, eastern and western Algeria. METHODOLOGY: a collection of 48 VREfm isolated from September 2010 to April 2017 in several Algerian hospitals were studied. Minimum inhibitory concentrations (MICs) were determined by E-test method according to CLSI guidelines. the detection of van genotype of all strains was performed by PCR. Clonal relationship of five VREfm targeted by region were characterized using multilocus sequence typing (MLST). RESULTS: All isolates have multidrug-resistance (MDR) and were resistant to at least five classes of antibiotics; however, all were susceptible to tigecycline and daptomycin with MIC50 at 0.094 µg/mL and 2 µg/mL respectively. All strains belonged to vanA genotype and have high level of resistance to vancomycin and teicoplanin. MLST revealed two sequence types (STs): ST80 (from the four regions of Algeria) and ST789, both belonging to the former hospital-adapted clonal complex CC17. CONCLUSIONS: the alarming dissemination of MDR E. faecium vanA and the ST80 in several regions of Algeria suggest a clonal spread of VREfm strains, which urgently require implementation of adequate infection control measures.