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The current study provides information on deep-water shrimps, Aristaeomorpha foliacea and Aristeus antennatus, which are trawled in the waters of the Mediterranean Sea off Damietta, Egypt, between January 2019 and December 2019. The catch comprised 62.68% of A. foliacea with a range from 16 to 65 mm in carapace length (CL) and 37.32% of A. antennatus with a range from 17 to 57 mm in CL. The overall sex ratio of females to males was 1.00:0.22 for A. foliacea and 1.00:0.47 for A. antennatus. Studying the length-weight relationship (LWR) revealed that A. foliacea and A. antennatus, females, males, and combined sexes, had negative allometric growth. Abdomen weight- total body weight relationship showed that A. antennatus had bigger mean abdomen weight indices than A. foliacea for females, males, and combined sexes. Age was studied based on the Bhattacharya length frequency method and four cohort age groups were predicted for A. antennatus and six cohort age groups for A. foliacea. The second cohort was the dominant age group for both species. For combined sexes, the von Bertalanffy growth parameters were K = 0.244, to = −0.072, and L∞ = 77.109 mm (CL) for A. foliacea, and K = 0.246, to = −0.689, and L∞ = 67.688 mm (CL) for A. antennatus. Total mortality (Z), natural mortality (M) and fishing mortality (F) were calculated as: Z = 0.670, M = 0.423, and F = 0.247 for A. foliacea, and Z = 1.295, M = 0.441, and F = 0.854 for A. antennatus. The exploitation ratio (E) revealed that the stock of A. foliacea was rationally exploited (E = 0.368) and the stock of A. antennatus was over-exploited (E = 0.659). At the current level of explotation, 39.23% of A. foliacea stock biomass and 15.35% of A. antennatus stock biomass were protected. Further studies are recommended to shed lights on the reproductive biology of these deep-water shrimp species.

Abstract This study investigated the dietary effects of coated l-ascorbic acid (LA) on growth, feed utilization, survival, serum biochemical indices, immunity, antioxidant capacity, and intestinal and hepatopancreatic histology of the pre-adult red swamp crayfish. Four isoproteinous and isolipidic diets were formulated to contain several LA levels as 0, 1300, 1600, and 1900 mg/kg and designated as control (LA0), LA13, LA16, and LA19, respectively. However, the analyzed LA concentrations in diets were 0.00, 199.57, 360.45, and 487.50 mg/kg in LA0, LA13, LA16, and LA19, respectively. Triplicate treatments of crayfish (21.60 ± 0.14 g) were fed the test diets and reared in fiberglass tanks with a density of 20 individuals per each for eight weeks. Results revealed that all LA treatments had significantly enhanced growth performance compared to the control. Of interest, the LA16 treatment recorded the highest final tank biomass, biomass gain, total feed intake, condition factor, and muscle yield among the other treatments. The tank feed conversion ratio was significantly decreased in LA treatments compared to the control. Moreover, dietary LA16 and LA19 had significantly higher survival rates (93.3%) compared to (85.0%) in the LA0 group. All dietary doses of LA significantly increased serum parameters (total protein, albumin, globulin, lysozyme activity) and respiratory burst activity compared to the LA0 treatment. Dietary LA16 significantly boosted the hepatopancreatic antioxidant capacity, manifested by decreased malondialdehyde concentrations, increased catalase, superoxide dismutase, and glutathione peroxidase enzyme activities, and reduced glutathione content compared to the LA-free diet. A normal histoarchitecture of the hepatopancreatic tubules was found in all LA treatments except with some minor degenerative changes in the tubular lumen, and hepatopancreatic cells associated with enlarged nuclei were found in the LA19. However, normal intestinal histoarchitecture was found in all treatments with no recorded intestinal lesions. Of interest, the polynomial regression performed on the analyzed LA concentrations suggested that 380 mg/kg would be suitable to provide maximal biomass gain for pre-adult crayfish. In conclusion, results revealed that coated LA could enhance the growth, immunity, and antioxidant capacity of pre-adult red swamp crayfish, suggesting its potential as a functional and necessary micronutrient for crayfish diets.

The purpose of this study is to assess long-term trends in Chl-a and SST in major fishing zones associated with fish production over an 18-year period (2002–2019) in the Gulf of Suez, Gulf of Aqaba, and the Red Sea proper. The study found that seasonal SST mean values ​​differed significantly (P

The objective of the current study was to describe the female reproductive characteristics of populations of the non-indigenous shrimp Penaeus latisulcatus off the Egyptian Mediterranean coast. P. latisulcatus was sampled from the commercial catch of Boughaz El-Maadiyah's landing center off the Mediterranean coast between July 2020 and June 2021. This study focused on describing maturity stages, calculating the gonadosomatic index (GSI), determining the spawning season, and measuring the size at first maturity of female P. latisulcatus. The stages of ovarian development were divided into six stages; i.e., immature, early maturing, late maturing, nearly ripe, ripe, and spent. A prolonged spawning season was identified, extending from the summer season to autumn and showing a peak in August. The GSI followed the same pattern of ovarian maturation and confirmed the spawning season of P. latisulcatus. As revealed, 50% of female individuals attained maturity at a total length of 11.34 cm. Hence, this study provides fundamental and helpful information for understanding the reproductive dynamics of P. latisulcatus on the Egyptian Mediterranean coast as a new habitat for its propagation. This information also helps in providing the proper management of fisheries and conservation of this shrimp species, which can be useful for aquaculture processes as well.

Penaeus latisulcatus (Kishinouye, 1896) is considered one of the most economically important penaeid shrimp species in the Egyptian Red Sea. Recently, it appeared in the Egyptian Mediterranean catches. The present study is concerned with the estimation of growth, age and population characteristics of the non-indigenous P. latisulcatus collected between the months of July 2020 to June 2021 from the landing fishing center of Boughaz El-Maadiyah (Egyptian Mediterranean coast). A total of 2214 individuals were collected monthly. The results showed that the females to males ratio was 1:0.98. According to the Chi-square test, there was no statistically significant difference between the sexes (X2 = 0.181, df = 1, P > 0.05). The distribution of the length frequency showed that the females varied from 5.0 cm to 19.2 cm (TL) with a mean length of 11.73 ± 2.78 cm, while the males ranged from 5.3 cm to 17.1 cm (TL) with a mean length of 10.97 ± 2.06 cm. Positive allometry was detected for the total length-total weight relationship. The parameters of von Bertalanffy were L∞ = 20.56 cm, K = 0.99 yr−1 and to = −0.178 yr−1 for females, L∞ = 18.68 cm, K = 1.05 yr−1 and to = −0.172 yr−1 for males, and L∞ = 20.74 cm, K = 0.90 yr−1 and to = −0.196 yr−1 for the combined sexes. The expected age of females and males were 2.6 and 2.2 years, respectively. According to the parameters obtained, the current exploitation rate of the population of P. latisulcatus was estimated at Ecur. = 0.59. The results indicated that the population of P. latisulcatus is being highly exploited in Boughaz El-Maadiyah landing center (Egyptian Mediterranean coast). Hence, it is important to manage the P. latisulcatus shrimp resources in the studied area. Furthermore, similar studies are recommended for P. latisulcatus along the Egyptian Mediterranean coast to evaluate variations between populations in different fishing areas. Moreover, further studies are needed about the new aspects of the reproductive activity of this species as well as its aquaculture to estimate its growth rate experimentally.

A total of 1457 random specimens of the newly established population of Metapenaeus affinis was collected monthly from the shrimp commercial catch at Boughaz El-Maadiyah landing center (Mediterranean Sea, Egypt) during the period from July 2020 to June 2021. This study aims to shed light on the growth pattern and stock assessment of this newly established species. The results showed that the catch of M. affinis varied in lengths between 5.4 cm and 16.0 cm TL. At length 13.5 cm, the population was composed of 100% females. The test of the allometric coefficients “b” of the total length (TL) – carapace length (CL) relationship showed negative allometry growth for males, females, and sexes combined. The values of “b” for the length-weight relationship reflected isometric growth for males, and a pattern of positive allometric growth was shown for females and sexes combined. The overall sex ratio (F:M) was 1.00:0.58 and the Chi-square test reflected high significant differences (χ2 = 100.68; df = 1; P

An unexpected new Metapenaeus shrimp species has arrived to the coastal water of Alexandria City, Egypt. Morphological and molecular studies were conducted for its identification. The results revealed that it is the Indo-West Pacific species, Metapenaeus affinis (H. Milne Edwards, 1837), which is considered as a new addition to the already present local penaeidae species; Metapenaeus monoceros (Fabricius, 1798) and Metapenaeus stebbingi (Nobili, 1904). Large numbers of Metapenaeus affinis were observed and collected by the Egyptian fishermen from the coastal waters of Alexandria City, Egypt, during the study period (2020–2021), which indicates its establishment in the area. A recommendation was presented for further studies regarding the suggested ways of introduction and the prediction for future new species appearance. Such phenomenon requires international efforts to deal with the non-indigenous species’ entries that are recently intensified on the global and regional level.

The distribution of eight heavy metals (Fe, Mn, Cu, Zn, Cr, Ni, Pb and Cd) in three species namely Pinctada radiata, Brachidontes pharaonis and Holothuria polii was determined seasonally from seven stations along Alexandria Coast, Mediterranean Sea, Egypt. Relatively the highest annual averages for each of the eight investigated metals during the period of the current study were found in Pinctada radiata. On the other hand, the lowest averages were found in Holothuria polii for Fe, Zn, Pb, Cr, Cu, Ni, and Cd, and in Brachidontes pharaonis for Mn (3.405 μg/g wet weight). In addition, the metal pollution assessment in mussels revealed that the total target hazard quotients were decreased in the order of Brachidontes pharaonis (0.198) > Holothuria polii (0.080) > Pinctada radiata (0.051). The target hazard quotients (THQs) values for each of the individual metal (Mn, Cu, Zn, Cr, Pb and Cd) in the investigated species were found much smaller than one, indicating that there is no human risk from their consumption.