The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.
Yield per recruit MSY Algeria This study is the first that deals with the stock status of the bogue Boops boops (Linnaeus, 1758) in the Eastern Algerian coast (Western Mediterranean). It aims is to estimate the important parameters needed to evaluate the dynamics of the stock of this species which is economically important resource in Algeria. The FiSAT II software has been used for data analysis. The total length and weight of the fishes sampled ranged from 10.1 to 30.9 cm and from 13.47 to 268.15 g, respectively. The longevity has been estimated at 5 years. The parameters of von Bertalanffy growth curve were L∞ = 32.03 cm, K = 0.28 yr-1 , t o =-1.13 years and ɸ' = 2.45. The lengthweight relationships was described by parameters a = 0.016 and b = 2.815, reflecting a trend towards negative allometric growth. The total mortality (Z), natural (M) and fishing (F) mortalities were 1.03, 0.37 and 0.66 yr-1 , respectively. The current exploitation rate (E) of the species was 0.64. The relative yield per recruit analysis (Y'/R) from the Beverton-Holt showed that the current level of exploitation is significantly higher than E max and E 0.5 (0.54 and 0.32 respectively), indicating that the population is overexploited and suffers from fishing pressure. For sustainable management of this resource, the current exploitation rate should be reduced by 50%.
Depuis au moins le début des années 1980, l’abondance continentale de l’anguille européenne a décliné à travers toute son aire de répartition, les causes avancées sont très nombreuses vues la complexité de son cycle biologique. Parmi les différentes menaces, nous citons les parasites qui détériorent l’état général du poisson l’empêchant ainsi de retourner sur son lieu de naissance pour boucler son cycle de reproduction et donc met en danger la pérennité de l’espèce. L’objectif premier de ce travail est de comparer l’infestation parasitaire par le nématode Anguillicoloïdes crassus des anguilles vivant dans 2 biotopes de salinité différente : le lac Oubeïra (eau douce) et la lagune Mellah (eau salée) (extrême Nord-Est de l’Algérie). Les taux d’infestation des anguilles capturées au cours des 3 années de suivi avoisinent les 4 % dans la lagune alors qu’ils sont 16 fois plus élevés dans le lac. En ce qui concerne les signes d’inflammation, toutes les anguilles du lac montrent des œdèmes et exsudats de cet organe alors que celles capturées au niveau de la lagune sont indemnes. Ces résultats nous permettent de conclure que la salinité est un facteur – sans doute déterminant – pour la survie de ce parasite et nous mène à proposer d’utiliser le sel comme moyen naturel pour le contrôle de cette parasitose.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.