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There is evidence that the European hake is one of the main target species of demersal fisheries in the Western Mediterranean and has been widely exploited for decades; the potential for overfishing is very high. The purpose of this study was to evaluate the stock assessment and the age validation of European hake ( Merluccius merluccius Linnaeus, 1758) in the GFCM/GSA 04 (Algerian eastern coast) in order to provide a management strategies and effective control measures. A total of 662 hake specimens were sampled from commercial landings from January 2021 to December 2021. The sex ratio was in favor of females (54.8%) but there were no differences in mean lengths between sexes. The estimated total mortality rate (Z) and the natural mortality (M) were 1.48 year − 1 and 0.41 year − 1 , respectively. The estimated instantaneous rate of fishing mortality (F) was calculated as 1.06 years − 1 , with an exploitation ratio of 0.72, which suggests that the stock in GSA 04 area could be overexploited (E > 0.5). The fishing mortality rate F = 1.06 is higher than the fishing mortality for maximum sustainable yield (Fmax = 0.43) corresponding to the fisheries mortality rate factor that maximizes equilibrium yield per recruit; hence the hazard ratio of the stock is being overfished. To limit the risk of stock collapse, adjustment of the F current fishing effort factor to F 0.1 (0.29) is essential, it should be reduced by 77% the fishing effort to increase by long term exploitable biomasses of hake stock and allow the renewal of the resource. The findings reported here provide new key instruments for the stock assessment of this species and thus contribute to it conservation.

Marek's disease (MD) is a huge problem for researchers due to the significant losses in bird flocks, but more importantly, the virus's mutagenic potential. The purpose of this study was to describe non-classical gross lesions observed in broilers and laying hens that suggest the disease emergence and re-emergence. The survey was conducted on 10 broiler and 4 laying hen flocks. All of the dead birds were necropsied in order to obtain a comprehensive diagnosis of lesions, analysing both macroscopic and microscopic alterations. Marek's disease occurred in 80% of cases in broilers and 100% of cases in layer hens. The disease struck 26-day-old broilers and hens at 2 weeks of age, causing a total mortality of 6% and 15%, respectively. There were no clinical indications of the classical neurological form of the disease in either rearing type, and tumour lesions were mostly detected in the liver, spleen, and ovarian follicles in layers, and in the proventriculus in broilers. These findings demonstrated that MD is widespread and that its resurgence is primarily manifested in visceral rather than neurological manifestations. Despite MD immunization, biosecurity remains critical.

The first objective of this study consists of an exhaustive description of growth, reproduction and age of 2 species of pelagic fish: the sardinella Sardinella aurita (N = 649) and the sardine Sardina pilchardus (N = 648). Samples were collected monthly from November, 2012 to October, 2013 along the Algerian eastern coasts. Concerning S. aurita, 7% was no identified (NI) against 22% of nonsexually differentiated (IM) individuals, 31% of males (M) and 40% of females (F). The relationship between the size and the weight revealed a majorant allometry (b = 3.13) from all material. The key size-age highlights that the majority of the IM (51) and adults (186) have a size included between: 8- 11 cm at 0-1 year and 16-17 cm at 3-4 years respectively. From S. pilchardus, the proportions of females are slight higher than males (42%-41%) against 12% of immature individuals and 5% of no identified individuals. Length-weight relationships revealed the equation: W = 0.005 L3.15 (sexes combined). The most important proportion of the males and females measures 12-15 cm at 3-4 years. Finally, estimated parameters of the von Bertalanffy model of both species were characterized.