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Parameters belonging to the physical status and gonadal size of certain fish provide crucial information for assessing both the productivity and fecundity of declining fish populations. These parameters are vulnerable to the negative impacts of disease agents such as internal or systemic parasites. Although parasitic diseases might influence these parameters, the literature investigating these pathophysiological alterations is scanty. Therefore, the current study represents one of the scarcest studies that document the possible link between parasitism, gonadal health, and the growth of European hake (Merluccius merluccius). Screening of imported European halves indicated a relatively high prevalence of Anisakis pegreffi Larvae 3 infestation, with an 80% prevalence rate, a mean intensity of 24.4, and a mean abundance of 19.5. However, the prevalence of Anisakid larvae infection in native fish was 36% with a mean intensity of 7.36 and mean abundance of 2.65.The current research revealed remarkable ovarian pathology that involved several forms of degenerative changes in ovarian tissues. Such gonadal pathologies were attributed to the damaging effect of the retrieved Anisakis pegreffi Larvae 3. Gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. Morphometric measurements of the gonads and body have revealed that, gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. [ABSTRACT FROM AUTHOR]

Vibriosis is a serious bacterial disease causing significant mortalities among farmed marine shrimp. The current study aimed to identify and characterize Vibrio spp. incriminated in the mass kills of the Litopenaeus vannamei shrimp from earthen ponds located in the vicinity of Lake Manzala in Shatta City, Damietta, Egypt. Moribund shrimp exhibited lethargic swimming behavior and redness/congestion of almost all body appendages and telson. Ponds' water parameters remarkably deteriorated. A high surge in water temperature (32°C), elevated levels of unionized ammonia (0.9 mg/L), and a remarkable decrease in dissolved oxygen (DO) (3mg/L) were all recorded during the period of disease outbreak and mortality episode from July through September 2021. Vibrio parahaemolyticus (30 isolates) and V. alginolyticus (23 isolates) were exclusively isolated from clinically affected shrimps collected during the mass kills episode. The identity of the retrieved isolates was confirmed through gene sequence and phylogenic analysis. Histopathological examination revealed different degrees of degeneration, sloughing, and necrotic changes through hepatopancreatic tissues together with marked inflammatory haemocytic infiltrations within the muscular tissues of the affected shrimps. A combined therapeutic strategy was adopted to stop mortalities and enhance shrimp health within the affected shrimp ponds. Permanent baths of hydrogen peroxide 40 % solution (in water) alternated with Yucca schidigera extract solution for 1week, together with Florfenicol powder at a dosage of 25 mg / Kg shrimp biomass in diet were very effective in reducing mortalities, improving swimming behavior, normalizing feeding intake, and enhancing the general health of the affected shrimps. [ABSTRACT FROM AUTHOR]

Heavy metals are considered among the most serious contaminants of aquatic ecosystems, due to their biomagnifications in the tissues of fish and humans. Thus, the current study was planned to shed the light on the importance of heavy metal biomonitoring on a regular basis to ensure high quality, healthy fish, and fish products for consumers. Laboratory assessment has indicated that the highest bioaccumulation pattern of Zinc (Zn), Copper (Cu), Cadmium (Cd), Lead (Pb) and Mercury (Hg) was recorded in Atlantic horse mackerel followed by Round Sardinella then Common panadora. Statistical analysis revealed the presence of relative variation in the accumulation patterns of heavy metals between different examined organs. The liver, spleen, and kidney have alternatively adopted the highest accumulation organ for Zn, Cu, Cd, Pb, and Hg, while gills were the least organ. The recorded histopathological alterations within liver, kidney, spleen, gills, and muscles have confirmed that Atlantic horse mackerel were the most affected fish species followed by Round sardinella then Common panadora. The study concluded that fish from the northwestern coast of Egypt are relatively healthier than fish from other coasts on the Mediterranean either from the European or Arabian side due to lower heavy metal levels in their flesh, and Atlantic horse mackerel could promote it as a biomonitor for heavy metal pollution. [ABSTRACT FROM AUTHOR]

The genotypic characterization of some bacterial pathogens that were incriminated in disease outbreaks among Haffara seabream "Rhabdosargus haffara" and marbled spinefoot "Siganus rivulatus" was investigated in full through the current study. A total of 250 fish samples (125 of each species) were collected along the Red Sea coasts of Hurghada City, Egypt. Fish samples were inspected for clinical signs, post-mortem changes, and bacteriological examination. The investigated fishes displayed septicemic signs and external skin lesions characteristic for streptococcosis and tenacibaculosis. Enterococcus spp., Streptococcus spp., and Flavobacterium spp. were isolated from moribund fishes using selective media. These isolates were phenotypically and genetically identified and characterized. The identities of bacterial isolates were confirmed as Enterococcus fecalis, Streptococcus iniae, Enterobacter cloacae, and Tenacibaculum maritimum based on sequencing the 16S rRNA gene. Enterococcus fecalis was the most common pathogen isolated from S. rivulatus and R. haffara and accounted for 46.8% and 47.8% of the total isolates, respectively. Accordingly, the present study proved that Enterocoocus spp., Streptococcus spp., and T. maritimum are important pathogenic bacteria incriminated in wild fish outbreaks in the Red Sea in Egypt. These findings proved the importance of regular and permanent bacteriological examination of wild fish to overcome fish mortalities, which lead to economic losses. Finally, sequencing and phylogenetic relationship techniques proved their usefulness as an ideal assay to develop a reliable, accurate, and rapid detection method for bacterial pathogens in the aquatic environment. [ABSTRACT FROM AUTHOR]