Breeding behaviour of the Kentish plover (Charadrius alexandrinus) in a salt marsh from the Eastern High Plateaux, northeast Algeria

The reproductive biology and nesting site selection of the Kentish plover, Charadrius alexandrinus, were investigated in a semi-arid salt marsh from the Eastern High Plateaux, northeast Algeria. The present study describes for the first time the breeding behaviour of this plover in the Eastern High Plateaux. On the natural ecosystem of Sebkhet Ouled M’Barek, egg-laying occurred from mid-April to late May, with peak in the last week of April. Mean clutch size was 2.71 ± 0.58 (n = 45), and incubation period was 27.0 ± 0.9 days. Hatching success amounted to 69.6% ± 6.4 (45 clutches) and an average of 2.0 ± 0.2 chicks hatched per nest. In this study we observed that incubating plovers usually nested near water edge and very close to a heterospecific nest. Three aspects make this population distinct from most other Kentish plover populations studied to date. It is characterised by a late onset of egg-laying, short egg-laying period and high rate of breeding success. Nevertheless, the present study shows that the mean clutch size, egg volume and incubation period were comparable to those known for other Mediterranean populations. Anthropogenic pressures, habitat loss as well as lack of management plans are major threats of this population

Les Monogènes parasites du genre Diplodus dans l'Est du littoral algérien

International audienceThis work is based on the study of the Monogenean parasite community of three species of the Teleostean fish Diplodus Rafinesque, 1810 (Sparidae): Diplodus sargus sargus (Linnaeus, 1758), D. annularis (Linnaeus, 1758) and D. vulgaris (E. Geoffroy St.- Hilaire, 1817) from various localities of the eastern Algerian coastline: the Gulfs of Skikda and Annaba, the coastline of El Kala, and the El Mellah lagoon. Observation of morphological and anatomical criteria of collected Monogeneans from all host species reveals the presence of 11 species, two thirds of which are related to the subclass Monopisthocotylea Odhner, 1912. The results of the distribution of parasitic indices at studied host species show that the prevalence and parasitic load vary from one host species to another and from one site to another. In the lagoon, where the parasite species richness is the lowest, the values of the intensity of infestation and abundance are however the highest. The highest parasitic loads are noted in Diplodus sargus sargus (Linnaeus, 1758) in all localities

Unusual cohabitation and competition between Planktothrix rubescens and Microcystis sp (cyanobacteria) in a subtropical reservoir (Hammam Debagh) located in Algeria

Succession in bloom-forming cyanobacteria belonging to distant functional groups in freshwater ecosystems is currently an undescribed phenomenon. However in the Hammam Debagh reservoir (Algeria), P. rubescens and Microcystis sp. co-occur and sometimes proliferate. With the aim of identifying the main factors and processes involved in this unusual cohabitation, water samples were collected monthly from February 2013 to June 2015 at the subsurface at four sampling stations and along the entire water column at one sampling station. In addition, the composition of the cyanobacterial communities was estimated by Illumina sequencing of a 16S rRNA gene fragment from samples collected over one year (October 2013-November 2014). This molecular approach showed that the Hammam Debagh reservoir displays high species richness (89 species) but very low diversity due to the high dominance of Microcystis in this community. Furthermore, it appears that Planktothrix rubescens and Microcystis sp. coexisted (from September to January) but proliferated alternately (Spring 2015 for P. rubescens and Spring 2014 and Autumn 2014/2015 for Microcystis). The main factors and processes explaining these changes in bloom-forming species seem to be related to the variation in the depth of the lake during the mixing period and to the water temperatures during the winter prior to the bloom season in spring

Cyanobacteria Dynamics in a Mediterranean Reservoir of the North East of Algeria: Vertical and Seasonal Variability

Harmful cyanobacterial efflorescence is of growing global concern and its prediction and management require a better understanding of the growth control factors and dominance of cyanobacteria. The Zit-Emba reservoir located in the North-East of Algeria, was constructed to provide drinking water, irrigation, and fishing. The vertical and seasonal distribution variation of cyanobacteria community associated with environmental factors was comprehensively investigated from April 2016 to December 2016 at five depths, based on a seasonal sampling. The cyanobacteria communities of this reservoir are composed of seven genera belonging to five orders. The average proportion of Microcystis to total cyanobacteria population was 43%, followed by Woronichinia 21%, Planktothrix 16%, Dolichospermum 13%, Oscillatoria 5%, and the remainder (Merismopedia, Spirulina) 2%. The average cyanobacterial abundance was 2702 cells/mL, ranging from 360 to 65 795 cells/mL and this abundance exceeds the alert level 1 throughout the year. The most recurrent periods of increase took place from spring to summer and autumn. However, the vertical distributions of cyanobacteria displayed a similar profile each season, and abundances tended to decrease with depth. The results of the statistical analysis suggested that the most abundant of cyanobacterial genera were positively related to chlorophyll-a and water temperature and negatively with the concentrations of NO3-N, NH4-N, and NO2-N. This demonstration of toxigenic cyanobacteria in this drinking water production dam involves regular monitoring of the cyanobacterial communities and cyanotoxins in raw water

Influence of site and host on parasites of two teleost fish in Algeria revealed by using indicator species analysis

International audienceThe indicator value methods are important to conservation biology because it is conceptually straight forward and allows researchers to identify bioindicators for any combination for habitat types or areas of interest. (Mc Geoch & Chown, 1998). The spatial distribution of parasitic copepods from teleost fishes (Chelon labrosus, Mugil cephalus, Liza aurata and Dicentrarchus labrax) was studied in two sites (Annaba gulf and El Mellah lagoon) in the eastern Algeria coastline using indicator species analysis (Indval) to identify parasite species as bioindicators of a given ecosystem during 2005-2008, also identified parasites as bioindicators relative to host. The randomization test identified four parasite species (Caligus mugilis, Ergasilus liza, Lernanthropus mugilis, Caligus minimus) having a significant indicator value for the site and six indicators for the host (Caligus mugilis, Ergasilus bora, Lernanthropus kroyeri, Lernanthropus mugilis, Caligus minimus, Ergasilus liza). Data on species composition and infection levels would help improve the monitoring and management of parasitism in Mugilidae and Moronidae populations. However none pointed out the role of parasitic copepods as bioindicators in Algerian costs

Dynamic of Filamentous Cyanobacteria in the Dam Ain Zada (North of Algeria)

Actually, harmful cyanobacterial efflorescence in Algerian water bodies used for drinking water are dominant throughout the year and their management requires a better knowledge of the cyanobacteria dynamics and the environmental parameters related to their dominance. The Ain Zada reservoir is a home of 5 genera. Occurrence frequency estimation of the identified genera shows the constancy of Planktothrix, the regularity of Aphanizomenon, Pseudanabaena and Cylindrospermopsis and the rarity of Oscillatoria. The dominating genus Planktothrix is represented exclusively by Planktothrix agardhii ; This species showed the highest proportion rates in winter (95.61 %), spring (94.80 %) and autumn (80.29 %) and the lowest in summer (29.16 %). Planktothrix agardii abundances show positive relation with suspended solids and chlorophyll a and negative relation with the depth of Secchi disc. Blooms of the potential toxinogenic Planktothrix agardhii and Cylindrospermopsis are related negatively. Results from cyanotoxins and pigments characterization showed a strong positive relation of Planktothrix agardhii abundance with microcystins (MCs) and phycocyanin (PC) concentrations. Indeed, in Ain Zada dam, we found that MCs contents have positive relation with water temperature and pH and negative relation with NO3. Our results show that, except for the months of March, October and November, the monthly abundances of cyanobacterial population recorded in Ain Zada dam exceeded the alert level 2. The filamentous species found in this dam are of great concern they are able to synthesize toxins harmful to aquatic and terrestrial organisms. Further research is needed to confirm the presence of other cyanotoxins (e.g. cylindrospermopsin) in Ain Zada dam

L’infestation par les hatshekiidae parasites de treize espèces de poissons téléostéens du littoral est algérien

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