Mesoscale variability in the trophic ecology of the European hake Merluccius merluccius in the Strait of Sicily

Hydrobiologia ◽  
2017 ◽  
Vol 821 (1) ◽  
pp. 57-72 ◽  
Author(s):  
E. Fanelli ◽  
P. Rumolo ◽  
M. Barra ◽  
G. Basilone ◽  
S. Genovese ◽  
...  
2017 ◽  
Vol 81 (1) ◽  
pp. 7 ◽  
Author(s):  
Capucine Mellon-Duval ◽  
Mireille Harmelin-Vivien ◽  
Luisa Métral ◽  
Véronique Loizeau ◽  
Serge Mortreux ◽  
...  

The European hake, Merluccius merluccius, is an important resource for Mediterranean fisheries. This study focuses on juvenile and adult hake feeding ecology in the Gulf of Lions, using information from scientific surveys carried out during two seasons and three years (2004-2006). Stomach content and stable isotope (δ15N, δ13C) analyses were performed, and the main factors explaining variations in δ15N were investigated using GLMs. In the Gulf of Lions, hake mostly fed on crustaceans and fish and a dominant piscivorous regime was reached at 15 cm total length. Pelagic fish (sardine, anchovy and small blue whiting) were the main source of prey (40%-80%) and cannibalism was low (< 5%). The results confirmed that hake is an opportunistic feeder and also showed that the size and diversity of prey vary among hake size classes, probably as a result of the different spatial distribution and/or foraging migrations. The present study finally postulates that the unbalanced sex ratio (80% female against 20% male) observed at the adult stage could be related to the combination of growth pattern differences, diet and exploitation rate on the continental shelf, where the males spend a longer period of time.


2018 ◽  
Vol 82 (S1) ◽  
pp. 199 ◽  
Author(s):  
Sergio Vitale ◽  
Marco Enea ◽  
Giacomo Milisenda ◽  
Vita Gancitano ◽  
Michele Luca Geraci ◽  
...  

Single-species Gadget models were used to assess the effects of using a sorting grid mounted on the traditional trawl net used by Sicilian trawlers to exploit the deep-water rose shrimp in the Strait of Sicily. The main commercial by-catch species of this fleet is the European hake (Merluccius merluccius), often caught at sizes well below the minimum conservation reference size. Selectivity curves based on the results of an experimental survey carried out in the area using a commercial trawler equipped with an ad hoc-designed sorting grid were incorporated into single-species Gadget models to forecast the effects of changing fishery selectivity on the performance of the two stocks in terms of catch and biomass. The models included catch data from the Italian, Tunisian and Maltese fleets as well as MEDITS trawl survey data for the period 2002-2016. Several scenarios were defined to simulate the effect of the Italian trawlers’ adopting the sorting grid under different stock-recruitment assumptions. The results obtained, when compared with status quo simulations of fishing without a sorting grid mounted on the trawl net, indicated a beneficial effect for both stocks in terms of an increase in biomass and for the fleets in terms of the amount and size composition of annual landings.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yasmin Abou-Rahma ◽  
Rewaida Abdel-Gaber ◽  
Amira Kamal Ahmed

The prevalence of infection and the identification of anisakid larvae in European hakeMerluccius merluccius lessepsianusfrom Hurghada City, Red Sea Governorate, Egypt, were investigated. Fish samples were collected during the period of February and November 2014. Twenty-two (36.66%) out of sixty examined fish specimens were found to be naturally infected withAnisakistype I larvae mostly found as encapsulated larvae in visceral organs. There was a positive relationship between host length/weight and prevalence of infection. Based on morphological, morphometric, and molecular analyses, these nematodes were identified as third-stage larvae ofAnisakis simplex. The present study was considered as the first report of anisakid larvae from European hake in the Egyptian water.


2021 ◽  
Vol 237 ◽  
pp. 105870 ◽  
Author(s):  
Joan Sala-Coromina ◽  
Jose Antonio García ◽  
Paloma Martín ◽  
Ulla Fernandez-Arcaya ◽  
Laura Recasens

Author(s):  
J.E. Cartes ◽  
J. Rey ◽  
D. Lloris ◽  
L. Gil de Sola

The feeding intensity and the diet of Merluccius merluccius were studied along a 1000 km latitudinal scale on the coasts of the Iberian Peninsula (western Mediterranean) in spring 2000. Merluccius merluccius was distributed along two bathymetric bands corresponding to the deep continental shelf (between 36 to 148 m), and the upper slope (between 215 to 310 m). At the shelf small crustaceans (mainly euphausiids and mysids) were dominant in the diet while fish (mainly Myctophidae) were the preferred prey on the slope. Feeding intensity of hake was significantly higher in areas with higher hake density suggesting feeding aggregations. Also, feeding intensity was significantly correlated with phytoplankton pigment concentrations (ppc), though only with ppc recorded one month before on the hake sampling stations. This delay between ppc and feeding intensity of hake may be a response to higher prey availability, because most hake prey were pelagic in origin (euphausiids, Clupeiformes) and they may reach high densities after exploiting local phytoplankton blooms. This delayed response seems to have more a local or spotted pattern. During three 8-h sampling cycles food consumed by hake ranged between 1·01 to 5·51% body wet weight (BWW), on average within the range of food consumption rates of other benthopelagic, active swimmer, fish.


2018 ◽  
Vol 70 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Sladjan Pavlovic ◽  
Slavica Borkovic-Mitic ◽  
Tijana Radovanovic ◽  
Branka Gavrilovic ◽  
Svetlana Despotovic ◽  
...  

We investigated the integrated response of antioxidant defense enzymes (total superoxide dismutase (TotSOD), manganese-containing superoxide dismutase (MnSOD), copper-zinc-containing superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and phase II biotransformation enzyme, glutathione- S-transferase (GST)) in the liver and white muscle of females of European hake (Merluccius merluccius L.) from the Adriatic Sea (Montenegro) in winter and spring. The activity of GSH-Px in the liver was significantly increased, while GST activity was decreased in spring compared to the winter. In white muscle, the activities of TotSOD and CuZnSOD were increased, while the activities of MnSOD, CAT, GSH-Px, GR and GST were decreased in spring when compared to the matching values in winter. The activities of TotSOD and CuZnSOD in winter were markedly lower in the muscle than in the liver, while the activity of MnSOD in the muscle was higher when compared to the liver. Principal component analysis (PCA) revealed clear separation of the investigated antioxidant biomarkers between tissues and seasons, while the integrated biomarker response (IBR) showed that the most intensive antioxidant biomarker response was in the liver in spring. Star plots of IBR showed a dominant contribution of glutathione-dependent biomarkers (GSH-Px, GR and GST) and CAT in both tissues and seasons with respect to SOD isoenzymes. All enzyme activities (except MnSOD) were greater in the liver in comparison to the white muscle. Our results show that the liver possesses a greater capacity to establish and maintain homeostasis under changing environmental conditions in winter and spring. At the same time, seasonal effects are more pronounced in muscle tissue.


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