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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.

This study investigates the growth pattern of 33 fish species caught by gillnets from the Egyptian Mediterranean waters off Alexandria between 2018 and 2020. This is accomplished by studying the length-weight relationship (LWR), Fulton’s condition factor (kc), the allometric condition factor (ka), and the relative weight condition factor (kn). The b-values of the length-weight relationship of the studied species varied between 2.1382 and 3.6868 according to the results. Only Dentex macrophthalmus (b = 2.1382), Etrumeus golanii (b = 2.4197), and Trichiurus lepturus (b = 3.6868) exhibited different values than the expected range of 2.5 1) is not necessarily a better condition for the fish. The study of the allometric condition factor (ka) assessed that the difference between ka and kc values influenced by the feeding intensity and the b-value. The values of the relative weight condition factor (kn) were within the range from 0.929 to 1.038, and 24 fish species reflected a good growth condition while the kn values for the remaining 9 species were less than 1.0. The obtained results add new data about specific species and provide updated data on the remaining species in the area of study. The obtained results can have useful effects on the stock assessment of fish species.

This study was conducted to estimate some biological aspects and fisheries assessment of Diplodus vulgaris caught by gillnets during the period 2018–2020 from the Egyptian Mediterranean waters of Alexandria. From an overall of 1004 individuals of D. vulgaris (10.0 – 24.0 cm TL) examined, lengths from 13.0 to 17.0 cm were representing 82.67% of the total fish number. The length-weight relationships for total and gutted weights of the D. vulgaris were: Log W = −1.7144 + 2.9063 Log L (R2 = 0.9982) and Log W = −1.8508 + 2.9903 Log L (R2 = 0.9967), respectively. The condition factor (k) was found to be fluctuating between 1.268 and 1.534 with an average value of 1.395 ± 0.0597. The overall sex ratio (M: F) was 1.00: 0.63 and the chi-square test revealed highly significant difference (χ2 = 24.80; df = 1; P

The present work deals for the first time with the species diversity of gillnets operated on the fisheries coasts of Alexandria City from El-Montazah to Sidi Kirayr. A total of 6161 specimens of about 427 kg were collected during periods from Feb 2018 to Jun 2018 and from Dec 2019 to Nov 2020 using two types of gillnets: the demersal and the pelagic gillnets. All samples were identified and photographed. A total of 108 species were identified in the catch of gillnets (99 fish species; 1 molluscan species and 8 crustacean species). From that, 28 lessepsian species were recognized. The catch was dominated by Family Sparidae (25 species) and Family Scombridae (8 species). The results showed that the species and size composition of gillnets catch were depending on the type of the gillnet and its mesh size. The catch of the demersal gillnets represented 63.27% of the total production by number and 84.72% by weight of the total catch of gillnets, while the catch of pelagic gillnets represented 36.73% and 15.28% by number and weight of the total catch, respectively. Eighty nine fish species were caught by the demersal gillnets and 36 fish species were caught by pelagic gillnets. Diplodus vulgaris was the main species caught by the demersal gillnets and Boops boops and Sardinella aurita were the main species caught by the pelagic gillnets. On the other hand, according to mesh number, which is defined as numbers of meshes in half-meter length of net, the gillnets with mesh number 17–18 followed by gillnets with mesh number 20 were the main meshes for the demersal gillnets. As for the pelagic gillnets, they were restricted to mesh number 33–34. In addition, only mesh numbers 11, 14, 17–18, 20 and 25–26 (demersal gillnets) and mesh numbers 33–34 (pelagic gillnets) were operated all over the year. Only 7 fish species from the target production were represented in all seasons namely: D. vulgaris, B. boops, Diplodus levantinus, Diplodus sargus, Umbrina cirrosa, Lithognathus mormyrus, and Trachurus mediterraneus. The seasonal diversity index of fish species was H' = 1. 3652 and the large numbers of fish species recorded were in spring (61 species) followed by autumn (58 species), summer (47 species), and winter (27 species). Further biological studies are needed to identify the most dominant species caught by the gillnets operated in Alexandria.

In the present study, morphometric and meristic characteristics of the cornetfishes, Fistularia spp., from the Egyptian Mediterranean coast were described. The linear length-length relationships and the allometric growth pattern were also investigated. Specimens were sampled from October 2017 to March 2019, by trawling in the marine area along the west of Alexandria City. The data analysis showed that the red cornetfish, Fistularia petimba (Lacepède, 1803), which is one of the IUCN Red List, was observed in this zone for the first time. Fistularia petimba dorsal, anal, pectoral, ventral, and caudal fins formulas were defined as follows: D 15; A 15; P (I + 14); V (i + 5); and C 18. This fish species was characterized by, elongated bony plates that were present anteriorly and posteriorly to the dorsal fin with a number of 23 bony plates anterior to the dorsal fin with the absence of gill rakers. Arched lateral line and sharp spines were on the posterior ossifications. The body color was orange–brown on the upper side and white on the bottom with transparent fins and a touch of orange color on the tips. The bluespotted cornetfish, Fistularia commersonii (Rüppell, 1838) reached 107.5 cm in total length. Its fins formulas were as follows: D (13–17); A (12 – 18); P (I + 13) – (I + 15); V (i + 5); and C 18. The vertebrae count was between 84 and 88, including the urostyle that had the first 4 vertebrae fused and without bony plate or gill rakers. Arched lateral line and rows of blue spots or line appeared on the back. The body color varied from brownish to olive on the upper side and white on the bottom with transparent fins and a touch of rosy pink color on the tips. The linear regression equations for the different morphometric characters of F. commersonii were highly correlated (R2 > 0.90). The allometric coefficients (b) of the various morphometric characters of F. commersonii were also studied. Further studies on the biological and fisheries parameters are recommended for F. commersonii as well as following the presence and establishment of F. petimba in the Egyptian waters.

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

Five cartilaginous fish species were recognized and identified as by-catch species during studying the catch of gill nets operated in the coastal area of Alexandria City from the Egyptian Mediterranean Waters during the study periods from Feb. 2018 to June 2018 and from Dec. 2019 to Nov. 2020. The by-catch included the first record of Pteroplatytrygon violacea, the closely related species Dasyatis pastinaca and Dasyatis tortonesei, the rarely found species Rhinoptera marginata, and the blackchin guitarfish Glaucostegus cemiculus. Among these five species, four species are listed in the IUCN Red List; as least concern for P. violacea, data deficient for D. pastinaca in the Mediterranean Sea, near threatened for R. marginata, and critically endangered for G. cemiculus. Morphological characters and morphometric measurements were studied to provide identification of these species. The species have been dissected for more biological information.

The present study aimed to analyze the non-target catch in the Egyptian Mediterranean waters, off Port Said, during the period from spring 2017 to winter 2018. The analysis revealed that from 75 non-target species, fish constituted about 69.4% of the total catch weight, whereas invertebrates reached about 30.6%. For non-target fish, 51 fishes were identified (50 bony fishes and one elasmobranch), of which 17 lessepsian species were found. The high percentage of fish (82.67%) was with an average length between 4.0 and

Reproductive biology of 803 specimens of Chrysichthys auratus from Damietta branch of the River Nile, Egypt was studied between January and December 2010. The overall sex ratio (M:F = 1:1.18) was significant at P

The present study sheds light on the growth pattern of the elephant snout fish (Mormyrus kannume, Mormyridae) in the Damietta branch of the Nile during the period from January to December 2010. This is done through studying the biometric characters, length–weight relationship, condition factors, growth performance index as well as the natural mortality. The linear regression for 15 morphometric characters in total length and 4 morphometric characters in head length was applied. The higher coefficient of the characters’ determinations which fit best was also applied. Five meristic characters were determined (dorsal fin rays, 49–69; pectoral fin rays, 12–15; ventral fin rays, 6; anal fin rays, 17–21 and vertebrae, 49–52). Fish length varied between 14.0 cm and 43.0 cm TL with a modal length range from 19 to 22 cm representing 61.36% of the fish sample. A length–weight relationship using the total weight was found to be LogW = −2.2218 + 3.063LogL (R2 = 0.997) and using the gutted weight was LogW = −2.1549 + 3.003LogL (R2 = 0.995) hence exhibiting isometric growth. The average condition factors for different lengths were 0.76 ± 0.06. The chi-square of the overall sex ratio (male:female = 1:0.42) was significant at P

The study of fishery biology of Chrysichthys auratus from Damietta branch, Egypt showed that the population has SL range of 7–20 cm, L′ = 11.85 cm. Males represent 45.90% and females 53.98% of the population. Length–length and length–weight relationships were analyzed for males, females and combined sexes. It was: SL = −0.6231 + 0.8402 TL and LogW = −1.6253 + 2.9832 LogSL for combined sexes, respectively. The highest values of condition factor were obtained in July, August and September for both sexes. The mean value of (K) for males was higher than those of females in all different lengths. Age was assessed by Bhattacharya’s (1967) method from length frequency data to estimate the von Bertalanffy growth parameters (L∞ = 26.53 cm, K = 0.214 and to = −1.569). The individuals of this species live for about 4 years and the first age dominates the population. The growth performance index in length (ФL) and weight (Фwt) was estimated as 2.18 and 1.11, respectively. The mortalities were computed as: Z = 1.44, M = 0.60 and F = 0.84. The exploitation rate was estimated as Ecur = 0.58. Length at first capture (Lc) was 9.66 cm at age 0.54 years. Length at recruitment (Lr) was 8.49 cm and age 0.35 years. It was found that the stock of Chrysichthys auratus in Damietta branch was rationally exploited.