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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.

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, t o = −0.072, and L ∞ = 77.109 mm (CL) for A. foliacea, and K = 0.246, t o = −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 FROM AUTHOR]

The brown meagre (Sciaena umbra Linnaeus, 1758) population has experienced dramatic population declines, and it was regionally assessed as "Near Threatened" in the Mediterranean. In this study, the current status of brown meagre populations in the Black Sea was evaluated by estimating growth and mortality rates based on age readings from the otolith. All specimens were collected by commercial trammel nets between March 2019 and February 2020 in the Turkish coast of the Black Sea. A total of 324 brown meagre were sampled during the study period, ranging in age from 0 to 26. The peak spawning season of the species was from June to July. The Von Bertalanffy growth parameters of (L8 = 54.15, k = 0.14 yr-1, t0 = -3.11) supports previous studies and suggests that brown meagre is a longlived and slow-growing species. The exploitation ratio of 0.53 for females and 0.47 for males. Life-history features and mortalities indicate that the brown meagre has relatively high fertility but may be undefended to intense fishing pressure. However, the impact of overfishing, pollution and climate change can have increasingly detrimental effects on the overall population size of this population. [ABSTRACT FROM AUTHOR]

The study of fishery biology and population dynamics was conducted for Boops boops collected from the commercial catches of gillnets operated in the Egyptian Mediterranean waters off Alexandria. A total of 880 specimens were sampled from the area between Sidi Kirayr to El-Montazah during the period 2018-2020. The length range varied between 11.0 and 20.0 cm TL with a mean of 13.98±1.19 cm and the total weight varied from 14 to 88 g with a mean total weight of 28.51±6.67 g. The length-weight relationship was computed as W= 0.0119 L2.9453 by using total weights and W= 0.0112 L2.9335 by using gutted weights. The mean condition factor (k) was 0.953±0.029 and the overall sex ratio (M: F) was 1.00:0.49. The von Bertalanffy growth parameters were estimated to be K= 0.38 yr-1, L∞= 27.85 cm and tο= -0.443 yr. The growth performance index (Фˋ) was 2.47. The values of natural (M), fishing (F) and total mortality (Z) were calculated as 0.865, 3.845 and 4.710 yr-1, respectively. The current exploitation ratio (Ecur= 0.816) is high reflecting the high exploitation of this species. The yield per recruit and the relative yield per recruit were also studied and the results confirmed that the stock of B. boops is highly exploited and the management of the pelagic gillnets is required. [ABSTRACT FROM AUTHOR]

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.

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 Log W = −1.6253 + 2.9832 Log SL 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 t o = −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 ( Ф L ) and weight ( Ф wt ) 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 E cur = 0.58. Length at first capture ( L c ) was 9.66 cm at age 0.54 years. Length at recruitment ( L r ) was 8.49 cm and age 0.35 years. It was found that the stock of Chrysichthys auratus in Damietta branch was rationally exploited. [ABSTRACT FROM AUTHOR]

• The variables are: section shape, fibers type and amount, loading protocol. • FRCM-confined concrete exhibits a multi-stage stress–strain curve. • Fibers strain exploitation ratio and volumetric dilation are evaluated. • FRCM jackets are activated after a certain amount of dilatancy has already occurred. • The envelope curve of the cyclic response is equivalent to the monotonic curve. In this work, the experimental behavior of confined concrete specimens subject to axial cyclic load is analyzed in terms of compressive strength, ductility, stress deterioration, plastic strain development, stiffness deterioration, fibers strain exploitation ratio and volumetric dilation. The following variables were considered, and their influence is discussed along the work: geometry of the cross-section (circular, square and two rectangular ones), fiber material (carbon and glass fibers) and number of layers (up to four for carbon-FRCM jackets), loading protocol (cyclic and monotonic). Results demonstrate that the envelope of the stress–strain curves obtained with cyclic loading coincides with the monotonic curve, for the range of variables analyzed here. Further, the stress–strain curve of FRCM-confined concrete has been modeled according to three different behaviors exhibited in this experimental campaign, being purely softening, softening with plateau, and hardening. [ABSTRACT FROM AUTHOR]