scholarly journals Links between parasitism, energy reserves and fecundity of European anchovy,Engraulis encrasicolus, in the northwestern Mediterranean Sea

2016 ◽  
Vol 4 (1) ◽  
pp. cov069 ◽  
Author(s):  
Dolors Ferrer-Maza ◽  
Josep Lloret ◽  
Marta Muñoz ◽  
Elisabeth Faliex ◽  
Sílvia Vila ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Energy Reserves ◽  
European Anchovy ◽  
Engraulis Encrasicolus ◽  
Northwestern Mediterranean Sea ◽  
European Anchovy Engraulis Encrasicolus ◽  
Northwestern Mediterranean

scholarly journals Parasitism, condition and reproduction of the European hake (Merluccius merluccius) in the northwestern Mediterranean Sea

2014 ◽  
Vol 71 (5) ◽  
pp. 1088-1099 ◽  
Author(s):  
Dolors Ferrer-Maza ◽  
Josep Lloret ◽  
Marta Muñoz ◽  
Elisabeth Faliex ◽  
Sílvia Vila ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Physical Condition ◽  
Reproductive Capacity ◽  
Energy Reserves ◽  
Merluccius Merluccius ◽  
Metazoan Parasites ◽  
Northwestern Mediterranean Sea ◽  
The Impact ◽  
Northwestern Mediterranean ◽  
European Hake

Abstract It is well known that parameters relating to physical condition and reproduction of fish provide essential data for estimating the productivity of exploited populations, as is the case with the European hake (Merluccius merluccius) in the northwestern Mediterranean Sea. Although parasitism might affect these parameters, research in this area is very scarce (and in the case of the Mediterranean almost non-existent). This study evaluates for the first time the potential link between parasitism, condition and reproduction of the European hake. Indicators of fish energy reserves (total lipid content in liver and gonads) and reproductive capacity (fecundity, egg quality and atresia) were evaluated, as were the prevalence and intensity of infection by metazoan parasites. The results indicate that the impact of anisakid nematodes is mostly negative and occurs mainly when hake are allocating their energy reserves to gonadal development. Although the results reveal a link between parasitism, condition and reproduction, we concluded that the northwestern Mediterranean hake population is in equilibrium with its metazoan parasites, which are not causing severe impairment to their physical condition or reproductive capacity.

scholarly journals Population structure of the European anchovy, Engraulis encrasicolus, in the SW Mediterranean Sea, and the Atlantic Ocean: evidence from otolith shape analysis

2014 ◽  
Vol 71 (9) ◽  
pp. 2429-2435 ◽  
Author(s):  
Mahmoud Bacha ◽  
Sherif Jemaa ◽  
Azzedine Hamitouche ◽  
Khalef Rabhi ◽  
Rachid Amara
Keyword(s):  
Population Structure ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Shape Analysis ◽  
Genetic Studies ◽  
European Anchovy ◽  
Otolith Shape ◽  
Otolith Shape Analysis ◽  
Engraulis Encrasicolus ◽  
European Anchovy Engraulis Encrasicolus

Abstract Understanding the influence of oceanographic features on the structure of fish population is of basic importance to population dynamics studies and fisheries management. The European anchovy (Engraulis encrasicolus) exhibits a complex population structure which has produced conflicting results in previous genetic studies. This study examines the variability in the shape of the anchovy's otolith as a tool for identifying different stocks, and investigates the effects of oceanographic features on population structure. Anchovies were analysed from seven locations in the SW Mediterranean Sea and Atlantic Ocean along the northwestern African (Morocco) and Portuguese (Bay of Cadiz) coasts. A combination of otolith shape indices and elliptic Fourier descriptors were investigated by multivariate statistical procedures. Within the studied area, three distinct anchovy stocks were identified: the Algero-Provençal Basin, the southern Alboran Sea, and the Atlantic Ocean (Morocco and Gulf of Cadiz). The separation of the stocks was based on non-parametric discriminant analysis returning a classification percentage. Over 81% of the separation of the stocks could be explained by oceanographic features. Shape variability of anchovy otoliths was associated with the presence of the Almeria-Oran front, and the strait of Gibraltar. The Alboran stock was distinct from the Algero-Provençal Basin and from the closest Atlantic stocks (Gulf of Cadiz or Atlantic coast of Morocco). Results are discussed and compared with those previously obtained by genetic studies. This study supports the efficiency of otolith shape analysis for the stock identification of anchovy, and highlights the role of oceanographic features in stock separation.

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